Copyright

Preface

Dedications

Acknowledgements

Chapter 1 Administration

Chapter 2 Definitions

Chapter 3 Use and Occupancy Classification

Chapter 4 Special Detailed Requirements Based on Use and Occupancy

Chapter 5 General Building Heights and Areas; Separation of Occupancies

Chapter 6 Types of Construction

Chapter 7 Fire and Smoke Protection Features

Chapter 8 Interior Finishes

Chapter 9 Fire Protection Systems

Chapter 10 Means of Egress

Chapter 11 Accessibility

Chapter 12 Interior Environment

Chapter 13 Energy Efficiency

Chapter 14 Exterior Walls

Chapter 15 Roof Assemblies and Rooftop Structures

Chapter 16 Structural Design

Chapter 17 Structural Tests and Special Inspections

Chapter 18 Soils and Foundations

Chapter 19 Concrete

Chapter 20 Aluminum

Chapter 21 Masonry

Chapter 22 Steel

Chapter 23 Wood

Chapter 24 Glass and Glazing

Chapter 25 Gypsum Board and Plaster

Chapter 26 Plastic

Chapter 27 Electrical

Chapter 28 Mechanical Systems

Chapter 29 Plumbing Systems

Chapter 30 Elevators and Conveying Systems

Chapter 31 Special Construction

Chapter 32 Encroachments Into the Public Right-Of-Way

Chapter 33 Safeguards During Construction or Demolition

Chapter 34 Reserved

Chapter 35 Referenced Standards

Appendix A Reserved

Appendix B Reserved

Appendix C Reserved

Appendix D Fire Districts

Appendix E Supplementary Accessibility Requirements

Appendix F Rodentproofing

Appendix G Flood-Resistant Construction

Appendix H Outdoor Signs

Appendix I Reserved

Appendix J Reserved

Appendix K Modified Industry Standards for Elevators and Conveying Systems

Appendix L Reserved

Appendix M Supplementary Requirements for One- And Two-Family Dwellings

Appendix N Assistive Listening Systems Performance Standards

Appendix O Reserved

Appendix P Type B+nyc Unit Toilet and Bathing Rooms Requirements

Appendix Q Modified National Standards for Automatic Sprinkler, Standpipe, Fire Pump and Fire Alarm Systems

Appendix R Acoustical Tile and Lay-In Panelceiling Suspension Systems

Appendix S Supplementary Figures for Luminous Egress Path Markings

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The provisions of this chapter shall apply to building and foundation systems in those areas not subject to scour or water pressure by wind and wave action. Buildings and foundations subject to such scour or water pressure loads shall be designed in accordance with Chapter 16 and Appendix G. (Note: Where the text in this Code refers to ASCE 7, the 2005 edition shall be used; and where the text in this Code refers to ASCE 7-10, the 2010 edition shall be used.)
Allowable bearing pressures, allowable stresses and design formulas provided in this chapter shall be used with the allowable stress design load combinations specified in Section 1605.3. The quality and design of materials used structurally in excavations and foundations shall conform to the requirements specified in Chapters 16, 19, 21, 22 and 23. Excavations and fills shall also comply with Chapter 33.
Where foundations are proportioned using the load combinations of Sections 1605.2 or 1605.3.1 and the computation of seismic overturning effects is by equivalent lateral force or modal analysis, the proportioning shall be in accordance with Section 12.13.4 of ASCE 7-10.
The following terms shall, for the purposes of this chapter, have the meanings shown herein.

AUGERED-CAST-IN-PLACE PILES. Augered-cast-in-place piles are constructed by pumping grout into an augered hole during the withdrawal of the auger. The pile is reinforced with a single reinforcing bar, a reinforcing steel cage or a structural steel section.

CAISSON PILES. Steel cased piles constructed by advancing a steel shell seated into rock and drilling of an uncased socket within the rock. The shell and socket are filled with a steel core section or steel reinforcing, and concrete or grout.

COMPACTED CONCRETE PILES. Compacted concrete piles are constructed by filling a driven casing with low-strength concrete and compacting the concrete as the casing is withdrawn.

COMPOSITE PILES. Composite piles consist of two or more approved pile types joined together.

CONCRETE-FILLED STEEL PIPE AND TUBE PILES. Concrete-filled steel pipe and tube piles are constructed by driving a steel pipe or tube section into the soil and filling the pipe or tube section with concrete. The steel pipe or tube section is left in place during and after the deposition of the concrete. For the purposes of this code these piles shall be considered driven piles.

DAMPPROOFING. Dampproofing is a protective measure applied to building foundation walls and slabs to prevent moisture from passing into interior spaces.

DEEP FOUNDATIONS. Deep foundations are comprised of concrete, grout, wood or steel structural elements either driven, drilled or jacked into the ground or cast in place. Deep foundations are relatively slender in comparison to their length, with lengths exceeding 12 times the least horizontal dimension. Deep foundations derive their load-carrying capacity through skin friction, end bearing, or a combination thereof.

DRIVEN UNCASED PILES. Driven uncased piles are constructed by driving a steel shell into the soil to shore an unexcavated hole that is later filled with concrete. The steel casing is lifted out of the hole during the deposition of the concrete. Driven uncased piles are not permitted under the provisions of this code.

ENLARGED BASE PILES. Enlarged base piles are cast-in-place concrete piles constructed with a base that is larger than the diameter of the remainder of the pile. The enlarged base is designed to increase the load-bearing area of the pile in end bearing. Enlarged base piles include piles installed by driving a precast concrete tip or by compacting concrete into the base of the pile to form an enlarged base.

HELICAL PILES. Helical piles are manufactured deep foundation steel elements consisting of a shaft and one or more helical bearing plates (helices) screwed into the ground by application of torque on the shaft. The various products marketed as screw piles, torque anchors, and helical piers are considered helical piles.

H-PILES. Steel H-piles are constructed by driving a steel H-shaped section into the ground.

FIXED HEADED PILE (DEEP FOUNDATION). A pile connected to a pile cap in a manner that prevents rotation of the pile head.

FREE HEADED PILE. A pile with a head that is free to rotate.

GEOTECHNICAL CAPACITY OF DEEP FOUNDATIONS. The load that can be supported by the soil or rock surrounding deep foundation as determined using a recognized method of analysis or as established by load tests. The geotechnical capacity can be developed through skin friction, end bearing, or a combination thereof.

LIQUEFACTION. For granular soils, liquefaction is defined as the loss of shear strength in soils resulting from increased pore-water pressure and reduced effective stress that may develop as a result of cyclic loading during earthquakes. For cohesive soils with a plasticity index of less than 20, liquefaction is defined as any transient softening and increased cyclic shear strains that may occur during earthquakes.

MICROPILE. A micropile is a drilled and grouted deep foundation element with a diameter that measures 5-inches (127 mm) to 14-inches (356 mm) that develops its load-carrying capacity by means of a bond zone in soil (also commonly known as a minipile).

PIER FOUNDATION. A pier foundation is a shallow foundation element of masonry or cast-in-place concrete construction. Piers are relatively short in comparison to their width, with lengths less than or equal to 12 times the least horizontal dimension of the pier. Piers derive their load-carrying capacity from end bearing on soil or rock.

RETAINING WALL. A wall that resists lateral or other forces caused by soil, rock, water or other materials, thereby limiting lateral displacement and the movement of the supported materials. Basement walls and vault walls that are parts of buildings and underground structures, including but not limited to utility vault structures, tunnels and transit stations, are not considered retaining walls.

SHALLOW FOUNDATION. A shallow foundation is an individual or strip footing, a mat foundation, a slab-on-grade foundation or a similar foundation element.

UNDERPINNING. The alteration of an existing foundation to transfer loads to a lower bearing stratum using new piers, piles, or other structural support elements installed below the existing foundation.

WATERPROOFING. Waterproofing is a protective measure applied to building foundation walls and slabs to prevent moisture and liquid water from passing into interior spaces.
Geotechnical investigations shall be subject to special inspections in accordance with Sections 1704.7, 1704.8 and 1704.9 and be conducted in conformance with Sections 1802.2 through 1802.7. An engineer shall scope, supervise and approve the subsurface investigation and the classification of the soil and rock encountered.
A geotechnical investigation shall be conducted for:

1. New structures;

2. Horizontal enlargements;

3. Vertical enlargements or alterations necessitating new foundations or resulting in additional loading that exceeds 5 percent of the existing foundation design capacity; or

4. As required by the commissioner or applicant of record.

The geotechnical investigation shall be performed in accordance with Sections 1802.4 through 1802.6. For structures in Seismic Design Category C or D, the requirements of Sections 1802.2.1 and 1802.2.2 shall also apply.
Where a structure is determined to be in Seismic Design Category C in accordance with Section 1613, the geotechnical investigation shall include an evaluation of the following potential hazards resulting from earthquake motions: slope instability, liquefaction and surface rupture due to faulting or lateral spreading. Peak ground acceleration for use in liquefaction analyses shall be determined in accordance with Section 1813.2.1.
Where a structure is determined to be in Seismic Design Category D in accordance with Section 1613, the requirements for Seismic Design Category C, given in Section 1802.2.1, shall be met. In addition, the following shall be conducted:

1. A determination of lateral pressures on basement, cellar, and retaining walls due to earthquake motions. Peak ground acceleration for use in lateral pressure analyses shall be determined in accordance with Section 1813.2.1.

2. An assessment of potential consequences of any liquefaction and soil strength loss, including estimation of differential settlement, lateral movement or reduction in foundation soil-bearing capacity. Mitigation measures shall be addressed. Such measures shall be given consideration in the design of the structure and shall include, but are not limited to, ground stabilization, selection of appropriate foundation type and depths, selection of appropriate structural systems to accommodate anticipated displacements or any combination of these measures.
Soil and rock classification shall be based on materials disclosed by borings, test pits or other subsurface exploration methods. Soil classifications shall be determined in accordance with ASTM D 2487 (refer to Table 1802.3) and the supplemental definitions contained herein. Rock classifications shall be determined in accordance with generally accepted engineering practice and the supplemental definitions contained herein. Laboratory tests shall be conducted to ascertain these classifications where deemed necessary by the engineer responsible for the geotechnical investigation or the commissioner.

BEDROCK.

1. Hard sound rock (Class 1a). Includes crystalline rocks, such as gneiss, granite, diabase and mica schist. Characteristics are as follows: the rock rings when struck with pick or bar; the rock does not disintegrate after exposure to air or water; the rock breaks with sharp fresh fracture; cracks are unweathered, less than 1/8-inch (3.2 mm) wide, and generally no closer than 3 feet (914 mm) apart; and the RQD (rock quality designation) with a double tube, NX-size diamond core barrel is generally 85 percent or greater for each 5-foot (1524 mm) run; or core recovery with BX-size core is generally 85 percent or greater for each 5-foot (1524 mm) run.

2. Medium hard rock (Class 1b). Includes crystalline rocks of paragraph (1) of this subdivision, plus marble and serpentinite. Characteristics are as follows: all those listed in paragraph (1) of this subdivision, except that cracks may be 1/4-inch (6.4 mm) wide and slightly weathered, generally spaced no closer than 2 feet (610 mm) apart; and the RQD with a double tube, NX-size diamond core barrel is generally between 50 and 85 percent for each 5-foot (1524 mm) run; or core recovery with BX-size core is generally 50 to 85 percent for each 5-foot (1524 mm) run.

3. Intermediate rock (Class 1c). Includes rocks described in paragraphs (1) and (2) of this subdivision, plus cemented shales and sandstone. Characteristics are as follows: the rock gives dull sound when struck with pick or bar; does not disintegrate after exposure to air or water; broken pieces may show moderately weathered surfaces; may contain fracture and moderately weathered zones up to 1 inch (25 mm) wide spaced as close as 1 foot (305 mm) apart; and the RQD with a double tube, NX-size diamond core barrel is generally 35 to 50 percent for each 5-foot (1524 mm) run; or a core recovery with BX-size core of generally 35 to 50 percent for each 5-foot (1524 mm) run.

4. Soft rock (Class 1d). Includes rocks described in paragraphs (1), (2), and (3) of this subdivision in highly weathered condition, plus talc schist and poorly cemented shales and sandstones. Characteristics are: rock may soften on exposure to air or water; may contain highly weathered zones up to 3 inches (76 mm) wide but filled with stiff soil; and either the RQD with a double tube, NX-size diamond core barrel is less than 35 percent for each 5-foot (1524 mm) run or core recovery with BX-size core of generally less than 35 percent for each 5-foot (1524 mm) run, or a standard penetration resistance more than 50 blows per foot (0.3 meters).

SANDY GRAVEL AND GRAVELS. Consists of coarse-grained material with more than half of the coarse fraction larger than the #4 size sieve and contains little or no fines (GW and GP). The density of these materials shall be determined in accordance with the following:

Dense (Class 2a). These materials have a standard penetration test N-value greater than 30 blows per 1 foot (0.3 meter).

Medium (Class 2b). These materials have a standard penetration test N-value between 10 and 30 blows per 1 foot (0.3 meter).

Loose (Class 6). These materials have a standard penetration test N-value less than 10 blows per 1 foot (0.3 meter). These materials shall be considered nominally unsatisfactory bearing materials.

GRANULAR SOILS. These materials are coarse-grained soils consisting of gravel and/or sand with appreciable amounts of fines, and gravel. Soil types include GM, GC, SW, SP, SM, and SC. The density of granular materials shall be determined in accordance with the following:

Dense (Class 3a). These materials have a standard penetration test N-value of greater than 30 blows per 1 foot (0.3 meter).

Medium (Class 3b). These materials have a standard penetration test N-value of between 10 and 30 blows per 1 foot (0.3 meter).

Loose (Class 6). These materials have standard penetration test N-value of fewer than 10 blows per 1 foot (0.3 meter). These materials shall be considered nominally unsatisfactory bearing materials.

CLAYS. For soil types SC, CL and CH in the absence of sufficient laboratory data, the consistency of clay materials shall be determined in accordance with the following:

Hard (Class 4a). Clay requiring picking for removal, a fresh sample of which cannot be molded by pressure of the fingers; or having an unconfined compressive strength in excess of 4 TSF (383 kPa); or having a standard penetration test where the N-value is greater than 30 blows per 1 foot (0.3 meter).

Stiff (Class 4b). Clay that can be removed by spading, a fresh sample of which requires substantial pressure of the fingers to create an indentation; or having an unconfined compressive strength of between 1 TSF (96 kPa) and 4 TSF (383 kPa); or having a standard penetration test where the N-value is between 8 and 30 blows per 1 foot (0.3 meter).

Medium (Class 4c). Clay that can be removed by spading, a fresh sample of which can be molded by substantial pressure of the fingers; or having an unconfined compressive strength of between 0.5 TSF (48 kPa) and 1 TSF (96 kPa); or having a standard penetration test where the N-value is between 4 and 8 blows per 1 foot (0.3 meter).

Soft (Class 6). Clay, a fresh sample of which can be molded with slight pressure of the fingers; or having an unconfined compressive strength of less than 0.5 TSF (48 kPa); or having a standard penetration test where the N-value is fewer than 4 blows per 1 foot (0.3 meter). This material shall be considered nominally unsatisfactory bearing material.

SILTS AND CLAYEY SILTS. For soil types ML and MH in the absence of sufficient laboratory data, the consistency of silt materials shall be determined in accordance with the following:

Dense (Class 5a). Silt with a standard penetration test where the N-value is greater than 30 blows per 1 foot (0.3 meter).

Medium (Class 5b). Silt with a standard penetration test where the N-value is between 10 and 30 blows per 1 foot (0.3 meter).

Loose (Class 6). Silt with a standard penetration test where the N-value is fewer than 10 blows per 1 foot (0.3 meters). This material shall be considered nominally unsatisfactory bearing material.
An engineer shall scope and supervise the geotechnical investigation. The geotechnical investigation shall be sufficient for evaluating soil and rock conditions including but not limited to material classification, stratigraphy, groundwater, slope stability, soil and rock strength, adequacy of load-bearing soils and rock, the effect of moisture variation on soil-bearing capacity, compressibility, liquefaction and expansiveness. The investigation shall comply with Sections 1802.4.1 through 1802.4.4.
The scope of the geotechnical investigation, including the number, types and depths of borings, the number of test pits or the number of alternative test methods; the equipment used to drill and sample; the in-situ testing; and the laboratory testing program shall be determined by the engineer responsible for the investigation, subject to the requirements of this chapter.

1. Borings shall be uniformly distributed under the structure or distributed in accordance with load patterns imposed by the structure.

2. As a minimum, investigations for structures shall include:

2.1. One exploratory boring for built-over areas up to and including 750 square feet (69.7 m2).

2.2. Two exploratory borings for built-over areas greater than 750 square feet (69.7 m2) but less than 5,000 square feet (465 m2), and at least one additional boring for each additional 2,500 square feet (233 m2), or part thereof, of built-over areas up to 20,000 square feet (1860 m2).

2.3 At least one boring for each additional 5,000 square feet (465 m2), or part thereof, of built-over areas in excess of 20,000 square feet (1860 m2).

3. At a minimum, investigations for retaining walls greater than 10 feet (3.05 m) in height shall include one exploratory boring for every 50 linear feet (15.24 m) of wall.

4. Borings shall be taken into bedrock, or to an adequate depth below the top of the load-bearing strata to demonstrate that the foundation loads have been sufficiently dissipated and to evaluate global stability of retaining walls.

5. For structures having an average area load (dead plus live) of 1,000 pounds per square foot (47.9 kN/m2) or more, at least one boring for every 10,000 square feet (930 m2) of footprint area shall penetrate at least 100 feet (30 480 mm) below the curb grade or 5 feet (1524 mm) into bedrock of Class 1c or better, whichever is less.

6. At least one-half of the borings satisfying this requirement shall be located within the limits of the built-up area and the remainder shall be within 25 feet (7620 mm) of the built-up area limits.

7. For structures to be supported on deep foundations, the required number of borings shall be not less than two borings, and based on a minimum of one boring per 2,000 square feet (609.6 m2) for the first 20,000 square feet (1860 m2) and one boring per every additional 4,000 square feet (609.6 m2).

8. All boring, sampling, and in-situ testing operations shall be subject to special inspection in accordance with Section 1704.7.4.

Exception: Test pits may be substituted for borings for one and two-story structures, and may be used only to establish the top of rock, where practical, for taller structures. For taller structures, the engineer shall submit a test pit observation report to the commissioner; for one and two-story structures, the registered design professional may submit a test pit observation report to the commissioner.
At the request of the engineer responsible for the geotechnical investigation, the suitable borings, test pits, probings, and the logs and records that were obtained as part of earlier exploration programs and that meet the requirements of this section may be used as partial fulfillment of the requirements of this section, subject to the approval of the commissioner. Additional borings shall be made at the direction of the engineer responsible for the geotechnical investigation when uncertainty exists as to the accuracy of the available information or specific new project or loading conditions indicate the need for additional information.
The geotechnical investigation shall determine the existing groundwater table.
In areas containing compressible soils, the geotechnical investigation shall determine the extent of these soils in the plan area of the structure and shall be subject to the requirements of Section 1802.3.
The soil boring and sampling procedures and apparatus shall be in accordance with ASTM D 1586 and ASTM D 1587 and generally accepted engineering practice. The rock coring, sampling procedure and apparatus shall be in accordance with ASTM D 2113 and generally accepted engineering practice. Rock cores shall be obtained with a double-tube core barrel with a minimum outside diameter of 27/8 inches (73 mm). With the approval of the engineer responsible for the geotechnical investigation, smaller-diameter double-tube core barrels may be used under special circumstances such as telescoping casing to penetrate boulders, or space limitations requiring the use of drill rigs incapable of obtaining large-diameter cores.
Where the foundation design relies on rock to support footings, piles or caisson sockets, a sufficient number of rock corings shall extend at least 10 feet (3048 mm) below the lowest level of bearing to provide assurance of the rock soundness. Where foundations are to rest on bedrock and such rock is exposed over a part or all of the area of the building, borings are not required in those areas where rock is exposed, provided the following requirements are met:

1. The presence of defects or the inclination of bedding planes in the rock are of such size and location so as not to affect stability of the foundation.

2. The foundation is not designed for bearing pressures exceeding those permitted in Table 1802.3.
The engineer responsible for the geotechnical investigation may engage specialized technicians to conduct alternative investigative methods such as cone penetrometer testing. Data from these investigations may be used to (1) supplement soil boring and rock coring information, provided there is a demonstrated correlation between the findings, and (2) determine material properties for static and seismic or liquefaction analyses. Subject to the approval of the commissioner, alternate exploration methods may replace borings on a one and one-half for one basis, but in no case shall there be fewer than half the required standard borings as per Section 1802.4.1, and no less than two standard borings. The boring depth requirements of Section 1802.4.1 shall be accomplished with borings. The alternative investigative methods must be capable of extending to the depths of the required borings. Other in-situ testing methods, such as geophysical, vane shear, and pressure meter, may be used to determine engineering design parameters, but may not be used as a substitute for the required number of borings.
Soil and rock samples shall be maintained in an accessible location by the permit holder or owner and made available to the engineer responsible for the geotechnical investigation and to the department, until the foundation work has been completed and accepted, or until 1 year after the investigation is complete, whichever is longer.
The owner or applicant of record shall submit a written report to the commissioner for any of the following conditions:

1. Any load-bearing value greater than those in Section 1804 is claimed.

2. The structure is determined to be in Seismic Design Category C or D in accordance with Section 1613.

3. Test pits are implemented in lieu of borings as per Section 1802.4.1.

4. The structure will bear on or above compressible soils (see Section 1804.2.2), uncontrolled fill (see Section 1804.2.3), or artificially treated soils (see Section 1804.2.4).

5. As required by the commissioner.
The geotechnical report shall be prepared by the engineer responsible for the geotechnical investigation and shall be signed and sealed. The report shall include, but need not be limited to, the following information:

1. A description of the planned structure.

2. A plot showing the location of test borings, excavations, probes, and/or other exploration techniques.

3. A complete record of the soil and/or rock sample descriptions.

4. A record of the soil and/or rock profile.

5. Elevation of the groundwater table, if encountered.

6. Results of in-situ or geophysical testing.

7. Results of laboratory testing.

8. Recommendations for foundation type and design criteria, including but not limited to allowable bearing capacity of natural or compacted soil and/or rock; mitigation of the effects of liquefaction (if applicable); differential settlement and varying soil and/or rock strength; and the effects of adjacent loads.

9. Expected total and differential settlement.

10. Special design and construction provisions for footings or foundations founded on expansive soils, as necessary.

11. Compacted fill material properties and testing in accordance with Section 1803.5.

12. Controlled low-strength material properties and testing in accordance with Section 1803.6.

13. A list of anticipated special inspections required for construction of earthwork and foundations.

14. For deep foundations reports, the requirements outlined in Section 1808.2.2.
Construction documents shall be prepared in accordance with Section 106.7.1.
Excavations for any purpose shall not remove vertical or lateral support from any foundation without first underpinning or protecting the foundation against settlement or lateral translation. Where required, underpinning or shoring shall be provided in accordance with Section 1814.
The excavation outside the foundation shall be backfilled with soil that is free of organic material, construction debris, or boulders. A controlled low-strength material (CLSM) can be used as backfill in lieu of soil. Soil backfill shall be placed in lifts and compacted in a manner that does not damage the foundation or the waterproofing or dampproofing material.

Exception: Controlled low-strength material need not be compacted.
The ground immediately adjacent to the foundation shall be sloped away from the structure as needed, or an approved alternate method of diverting water away from the foundation shall be used, where surface water would detrimentally affect the foundation material (soil and/or rock). Grading shall not be detrimental to the bearing material of adjacent structures. Site grading shall also comply with Section 1101.11 of the New York City Plumbing Code.
In an excavation where soil and groundwater conditions are such that an inward or upward seepage might be produced in materials intended to provide vertical or lateral support for foundation elements or for adjacent foundations, excavating methods shall control or prevent the inflow of ground water to prevent disturbance of the soil material in the excavation or beneath existing buildings. No foundation shall be placed on soil that has been disturbed by seepage unless remedial measures have been taken.
Grading and/or filling in areas of special flood hazard shall not be permitted except as permitted in Appendix G.
Where foundations will bear on compacted fill material, the compacted fill shall comply with the provisions of a geotechnical report prepared, signed and sealed by the engineer, which shall contain the following:

1. Specifications for the preparation of the site prior to placement of compacted fill material.

2. Specifications for material to be used as compacted fill.

3. Test method(s) to be used to determine the maximum dry density and optimum moisture content of the material to be used as compacted fill.

4. Maximum allowable thickness of each lift of compacted fill material.

5. Field test method(s) for determining the in-place dry density of the compacted fill.

6. Minimum acceptable in-place dry density expressed as a percentage of the maximum dry density determined in accordance with Item 3.

7. Number and frequency of field tests required to determine compliance with Item 6.

8. Acceptable types of compaction equipment for the specified fill materials.
Where footings will bear on controlled low-strength material (CLSM), the CLSM shall comply with the provisions of a geotechnical report prepared, signed and sealed by the engineer, which shall contain the following:

1. Specifications for the preparation of the site prior to placement of the CLSM.

2. Specifications for the CLSM.

3. Laboratory or field test method(s) to be used to determine the compressive strength or bearing capacity of the CLSM.

4. Test methods for determining the acceptance of the CLSM in the field.

5. Number and frequency of field tests required to determine compliance with Item 4.
The allowable bearing pressures provided in Table 1804.1 shall be used with the allowable stress design load combinations specified in Section 1605.3.

TABLE 1804.1 ALLOWABLE BEARING PRESSURES

CLASS OF MATERIALS
(Notes 1 and 3)
MAXIMUM ALLOWABLE BEARING
PRESSURE (TSF)
MAXIMUM ALLOWABLE BEARING
PRESSURE (kPa)
1. Bedrock (Notes 2 and 7)
1a Hard sound rock 60 5,746
1b Medium rock 40 3,830
1c Intermediate rock 20 1,915
1d Soft rock 8 766
2. Sandy gravel and gravel (GW, GP) (Notes 3, 4, 8, and 9)
2a Dense 10 958
2b Medium 6 575
3. Granular soils (GC, GM, SW, SP,SM, and SC) (Notes 4, 5, 8, and 9)
3a Dense 6 575
3b Medium 3 287
4. Clays (SC, CL, and CH) (Notes 4, 6, 8, and 9)
4a Hard 5 479
4b Stiff 3 287
4c Medium 2 192
5. Silts and silty soils (ML and MH) (Notes 4, 8, and 9)
5a Dense 3 287
5b Medium 1.5 144
6. Nominally Unsatisfactory Bearing Materials: See 1804.2.1 See 1804.2.1
Loose granular soils
Soft clay soils
Loose Silt
• All organic silts, organic clays, peats, soft clays, granular soils and varved silts
7. Controlled and uncontrolled fills See 1804.2.2 or 1804.2.3 See 1804.2.2 or 1804.2.3

Notes:
1. Where there is doubt as to the applicable classification of a soil or rock stratum, the allowable bearing pressure applicable to the lower class of material to which the given stratum might conform shall apply.
2. The tabulated values of allowable bearing pressures apply only for massive rocks, or for sedimentary or foliated rocks where the strata are level or nearly so, and then only if the area has ample lateral support. The allowable bearing pressure for tilted strata and their relation to nearby slopes or excavations shall be evaluated by the engineer responsible for the geotechnical investigation. The tabulated values for Class 1a materials (hard sound rock) may be increased by 25 percent provided the engineer performs additional tests and/or analyses substantiating the increase.
3. For intermediate conditions, values of allowable bearing pressure shall be estimated by interpolation between indicated extremes.
4. Footing embedment in soils shall be in accordance with Section 1805.3 and the width of the loaded area shall not be less than 18 inches (457 mm), unless analysis demonstrates that the proposed construction will have a minimum factor of safety of 2.0 against shear failure of the soil.
5. Estimates of settlements shall govern the allowable bearing pressure, subject to the maximums given in this table, and as provided in Section 1804.2.
6. Allowable bearing pressure of clay soils shall be established on the basis of the strength of such soils as determined by field or laboratory tests and shall provide a factor of safety against failure of the soil of not less than 2.0 computed on the basis of a recognized procedure of soils analysis, shall account for probable settlements of the building and shall not exceed the tabulated maximum values.
7. Allowable bearing pressure may be increased due to embedment of the foundation. The allowable bearing pressure for intermediate rock (1c), medium hard rock (1b), and hard sound rock (1a) shall apply where the loaded area is on the rock surface. Where the loaded area is below the rock surface and is fully confined by the adjacent rock mass and provided that the adjacent rock mass above the bearing surface is of the same rock class or better, and the rock mass has not been shattered by blasting or otherwise is or has been rendered unsound, the allowable bearing pressure may be increased 10 percent of the base value for each 1 foot (0.3 meters) of embedment below the surface of the adjacent rock surface in excess of 1 foot (0.3 meters), but shall not exceed 200 percent of the values.
8. The allowable bearing pressure for soils of Classes 2, 3, 4, and 5 determined in accordance with Notes 3, 4, and 5 above, shall apply where the loaded area is embedded 4 feet (1219 mm) or less in the bearing stratum. Where the loaded area is embedded more than 4 feet (1219 mm) below the adjacent surface of the bearing stratum, and is fully confined by the weight of the adjacent soil, the allowable bearing pressure may be increased 5 percent of the base value for each 1-foot (305 mm) additional embedment, but shall not exceed twice the values. Increases in allowable bearing pressure due to embedment shall not apply to soft rock, clays, silts and soils of Classes 6 and 7.
9. The allowable bearing pressure for soils of Classes 2, 3, 4, and 5 determined in accordance with this table and the notes thereto, may be increased up to 1/3 where the density of the bearing stratum below the bottom of the footings increases with depth and is not underlain by materials of a lower allowable bearing pressure. Such allowable bearing pressure shall be demonstrated by a recognized means of analysis that the probable settlement of the foundation due to compression, and/or consolidation does not exceed acceptable limits for the proposed building.
10. The maximum toe pressure for eccentrically loaded footings may exceed the allowable bearing pressure by up to 25 percent if it is demonstrated that the heel of the footing is not subjected to tension.
The allowable bearing pressure for supporting soil and rock at or near the surface shall not exceed the values specified in Table 1804.1, unless data to substantiate the use of a higher value are developed and contained in the engineer’s geotechnical report, and the commissioner approves such value. Allowable bearing pressure shall be considered to be the pressure at the base of a foundation in excess of the stabilized overburden pressure existing at the same level prior to construction operations.

TABLE 1804.2 UNIFIED SOIL CLASSIFICATION (Including Identification and Description

MAJOR DIVISIONS GROUP SYMBOLS TYPICAL NAMES FIELD IDENTIFICATION PROCEDURES (EXCLUDING PARTICLES LARGER THAN 3 IN. AND BASING FRACTIONS ON ESTIMATED WEIGHTS) INFORMATION REQUIRED FOR DESCRIBING SOILS LABORATORY CLASSIFICATION CRITERI
1 2 3 4 5 6 7
Coarse-grained Soils More than half of material is larger than No. 200 sieve size. The No. 200 sieve size is about the smallest visible to the naked eye. Gravels More than half of coarse fraction is larger than No. 4 sieve size. (For visual classification. the 1/4 -in. size may be used as equivalent to the No. 4 sieve size.) Clean Gravels (Little or no fines) GW Well-graded gravels, gravel-sand mixture, little or no fines. Wide range in grain size and substantial amounts of all intermediate particle sizes For undisturbed soils add information on stratification, degree of compactness, cementation, moisture condition, and drainage characteristics. Use grain-size curve in identifying the fractions as given under field identification. Determine percentage of gravel and sand from grain-size curve. Depending on percentage of fine
(fraction smaller than No. 200 sieve size) coarse-grained soils are classified as follows: Less than5% GW,GP,SW,SP, More than12% GM,GC,SM,SC. 5% to 12% Borderline cases requiring use of dual symbols.
GP Poorly graded gravels or gravel-sand mixture, little or no fines. Predominantly one size or a range of sizes with some intermediate sizes missing. Not meeting all gradation requirements for GW
Gravels with Fines (Appreciable amount of fines) GM Silty gravels, gravel and silt mixtures. Nonplastic fines or fines with low plasticity (for identification procedures see ML below). Give typical name; indicate approximate percentages of sand and gravel, maximum size; angularity, surface condition, and hardness of the coarse grains; local or geologic name and other pertinent descriptive information; and symbol in parentheses. Atterberg limits below "A" line or P1 less than 4 Above "A" line with P1 between 4 and 7are borderline cases requiring use of dual symbols.
GC Clayey gravels, gravel and clay mixtures. Plastic fines (for identification procedures see CL below). Atterberg limits above "A" line with P1 greater than 7
Sands More than half of coarse fraction is smaller than No .4 sieve size. Clean Sand (Little or no fines) SW Well-graded sands, gravelly sands, little or no fines. Wide range in grain size and substantial amounts of all intermediate particle sizes.
SP Poorly graded sands or gravelly sands, little or no fines. Predominantly one size or a range of sizes with some intermediate sizes missing. Example: Silty sand, gravelly; about 20% hard, angular gravel particles 1/2-in. maximum size; rounded and subangular sand grains, coarse to fine; about 15% nonplastic fines with low dry strength; well compacted and moist in place; alluvial sand; (SM). Not meeting all gradation requirements for SW
Sands with Fines
(Appreciable amount of
fines)
SM Silty sands, sand-silt mixtures. Nonplastic fines or fines with low plasticity (for identification procedures see ML below). Atterberg limits above "A" line or P1 less than 4 Limits plotting in hatched zone with P1 between 4 and 7are borderline cases requiring use of dual symbols.
Fine-grained Soils More than half of material is smaller than No. 200 sieve size SC Clayey sands, sand-clay mixtures. Plastic fines (for identification procedures see CL below). Atterberg limits above "A" line with Pl greater than 7
Identification Procedure on Fraction Smaller than No.40SieveSize.
Dry Strength
(Crushing
Characteristics)
Dilatancy (Reaction to shaking) Toughness (Consistency near PL)
Silts and Clays Liquid limit is less than 50 ML Inorganic silts and very fine sands,
rock flour, silty or clayey fine sands or clayey silts with slight plasticity.
None to slight Quick to slow None For undisturbed soils add information on structure, stratification, consistency in undisturbed and remolded states, moisture and drainage conditions Plasticity Index
CL Inorganic clays of low to medium plasticity, gravelly clays, sandy clays, silty clays, lean clays. Medium to high None to very slow Medium
Silts and Clays Liquid limit is greater than 50 OL Organic silts and organic silty clays of low plasticity. Slight to medium Slow Slight Give typical name; indicate degree and character of plasticity; amount and maximum size of coarse grains; color in wet condition; odor, if any; local or geologic name and other pertinent descriptive information; and symbol in parentheses.
MH Inorganic silts, micaceous or diatomaceous fine sandy or silty soils, elastic silts. Slight to medium Slow to none Slight to medium
CH Inorganic clays of high plasticity, fat clays. High to very high None High
OH Organic clays of medium to high plasticity, organic silts. Medium to high None to very slow Slight to medium Example: Clayey silt, brown; slightly plastic; small percentage of fine sand; numerous vertical root holes; firm and dry in place; loess; (ML)
Highly Organic Soils Pt Peat and other highly organic soils. Readily identified by color, odor, spongy feel and frequently by fibrous texture
1. Boundary classifications: Soils possessing characteristics of two groups are designed by combinations of group symbols. For example GM-GC, well-graded gravel-sand mixture with clay binder.
2. All sieve sizes on this chart are U.S. standard.
3. Adopted by Corps of Engineers and Bureau of Reclamation, January 1952. 032058C
Organic silts, organic clays, peats, soft clays, loose granular soils, loose silts, and varved silts shall be considered nominally unsatisfactory bearing material. The allowable bearing pressure shall be determined independently of Table 1804.1 subject to the following:

1. For varved silts, the soil bearing pressure produced by the proposed building shall not exceed 2 tons per square foot (192 kPa), except that for desiccated or over consolidated soils, higher bearing pressures are allowed subject to approval by the commissioner.

2. For organic silts or clays, peats, soft clays, loose granular soils, or loose silts, the engineer responsible for the geotechnical investigation shall establish the allowable soil bearing pressure based upon the soil’s specific engineering properties. This may require that the soils be preconsolidated, artificially treated or compacted.

3. A report prepared, signed and sealed by the engineer is required to be filed with the department to substantiate the design soil pressures to be used on soil materials and shall contain, at a minimum:

3.1. Sufficient laboratory test data on the compressible material to indicate the soil strength and the preconsolidation pressure, coefficient of consolidation, coefficient of compressibility, permeability, secondary compression characteristics, and Atterberg limits.

3.2. Where the design contemplates improvement of the natural bearing capacity and/or reduction in settlements by virtue of preloading, cross sections showing the amount of fill and surcharge to be placed, design details showing the required time for surcharging, and computations showing the amount of settlement to be expected during surcharging and the estimated amount and rate of settlement expected to occur after the structure has been completed, including the influence of dead and live loads of the structure.

3.3. A detailed analysis showing that the anticipated future settlement will not adversely affect the performance of the structure.

3.4. Where strip drains, sand drains, or stone columns are to be used, computations showing the diameter, spacing, and anticipated method of installation of such drains.

3.5. Records of settlement plate elevations and pore pressure readings, before, during, and after surcharging.
Fills shall be considered as satisfactory bearing material of the applicable class when placed in accordance with the following procedures and subject to the special inspection provisions of Chapter 17:

1. Area to be filled shall be stripped of all organic materials, rubbish and debris.

2. Fill shall not be placed when frozen or on frozen or saturated subgrade.

3. The special inspection agency shall approve the subgrade prior to fill placement.

4. Fill material shall consist of gravel, crushed rock, recycled concrete aggregate, well-graded sand or a mixture of these, or equivalent materials with a maximum particle size of 3 inches (76.2 mm‡) and a maximum of 10 percent passing the #200 sieve.

5. Fill shall be placed and compacted in lifts, not exceeding 12 inches (305 mm), at its optimum moisture content, plus or minus 2 percent, and to not less than a density of 95 percent of the optimum density as determined by ASTM D 1557.

6. Fill density shall be verified by in-place tests made on each lift.
Provided the capacity of the underlying soil is not exceeded, the allowable bearing pressure of controlled fill shall be limited to:

1. 6 tons per square foot (766 kPa) for gravel and crushed rock.

2. 3 tons per square foot (383 kPa) for recycled concrete aggregate and well-graded sand.
Fills other than controlled fill may be considered as satisfactory bearing material of applicable class, subject to the following:

1. Where spread footings will be used, the soil within the built-up area shall be explored using test pits at every column. All test pits shall extend to depths equal to the smaller width of the footing and at least one test pit shall penetrate at least 8 feet (2438 mm) below the level of the bottom of the proposed footings. All test pits shall be backfilled with properly compacted fill. Borings may be used in lieu of test pits, provided that continuous samples of at least 3 inches (76 mm) in diameter are recovered. Where mat foundations will be used, one test pit or minimum 3 inch (76 mm) diameter sampler boring shall be provided for every 1,000 square feet (232.3 m2) of building footprint area. For continuous concrete footings, one test pit or minimum 3 inch (76 mm) diameter sampler boring shall be provided for every 25 linear feet (7.62 m).

2. The building area shall be additionally explored using one standard boring for every 2,500 square foot (232.3 m2) of building footprint area. These borings shall be carried to a depth sufficient to penetrate into natural ground, but not less than 20 feet (6096 mm) below grade.

3. The fill shall be composed of material that is free of voids and free of extensive inclusions of mud and organic materials such as paper, wood, garbage, cans, or metallic objects and debris.

4. The allowable soil bearing pressure on satisfactory uncontrolled fill material shall not exceed 2 tons per square foot (192 kPa). One and two-family dwellings may be founded on satisfactory uncontrolled fill provided the dwelling site has been explored using at least one test pit, penetrating at least 8 feet (2438 mm) below the level of the bottom of the proposed footings, and the fill has been found to be composed of material that is free of voids and generally free of mud and organic materials, such as paper, garbage, cans, or metallic objects, and debris. Test pits shall be backfilled with properly compacted fill.
Nominally unsatisfactory soil materials that are artificially compacted, cemented, or preconsolidated may be used for the support of buildings, and nominally satisfactory soil materials that are similarly treated may be used to resist soil bearing pressures in excess of those indicated in Table 1804.1. The engineer shall develop treatment plans and procedures and post-treatment performance and testing requirements, and submit such plans, procedures, and requirements to the commissioner for approval. After treatment, a sufficient amount of sampling and/or in-situ tests shall be performed in the treated soil to demonstrate the efficacy of the treatment for the increased bearing pressure.
Shallow foundations shall be designed and constructed in accordance with Sections 1805.1 through 1805.9. Shallow foundations shall be constructed on suitable bearing materials established in accordance with the requirements of Sections 1803 and 1804.
The top surface of footings shall be level. The bottom surface of footings is permitted to have a slope not exceeding one unit vertical in 10 units horizontal (10 percent slope). Footings shall be stepped where necessary to change the elevation of the top surface of the footing or where the surface of the ground slopes more than one unit vertical in 10 units horizontal (10 percent slope).
The minimum depth of shallow foundations below the undisturbed ground surface shall be 12 inches (305 mm). Where applicable, the depth of shallow foundations shall also conform to Section 1805.3.1.
Except where otherwise protected from frost, shallow foundations, pile caps, and other permanent supports of buildings and structures shall be protected from frost by one or more of the following methods:

1. Extending a minimum of 4 feet (1219 mm) below the lowest adjacent permanent exposed grade;

Exception: Grade beams shall be embedded a minimum of 18 inches below the lowest adjacent permanent exposed grade.

2. Constructing in accordance with ASCE-32; or

3. Erecting on solid rock.

Exception: Free-standing buildings meeting all of the following conditions are not required to be frost protected:

1. Classified in Structural Occupancy Category I (see Table 1604.5);

2. Area of 400 square feet (37 m2) or less; and

3. Eave height of 10 feet (3048 mm) or less.
Shallow foundations shall not bear on frozen soil.

Exception: Temporary structures may bear on frozen soil if the soil is maintained in a frozen condition throughout the service life of the temporary structures being supported. The method of maintaining the soil in a frozen condition shall be approved by the commissioner.
Where shallow foundations are supported at different levels, or are at different levels from the shallow foundations of adjacent structures, the influence of the pressures under the higher foundation on the stability of the lower foundations shall be considered in the design. The design shall consider the requirements for lateral support of the material supporting the higher foundation, the additional load imposed on the lower foundations, and assessment of the effects of dragdown on piles supporting adjacent buildings or compression of soils supporting adjacent buildings.
Shallow foundations shall be designed and constructed in accordance with Sections 1805.5.1 through 1805.5.6.
Shallow foundations shall be designed so that the allowable bearing capacity of the soil is not exceeded, and that differential settlements are within the allowable limits for the structure. The minimum width of shallow foundations shall be 18 inches (457 mm).
Shallow foundations shall be designed for the most unfavorable effects due to the combinations of loads specified in Section 1605.3. The dead load shall include the weight of shallow foundations and overlying fill. Reduced live loads, as specified in Section 1607.9, are permitted to be used in the design of shallow foundations.
Where machinery operations or other vibrations are transmitted through the shallow foundations, consideration shall be given in the shallow foundation design to prevent detrimental disturbances of the soil.
When the possibility of shifting or moving soil exists, the short and long term impact of such soils shall be considered in the design of shallow foundations.
The design, materials and construction of concrete shallow foundations shall comply with Sections 1805.5.2.1 through 1805.5.2.5 and the provisions of Chapter 19.
Concrete in shallow foundations shall have a specified compressive strength (f'c) of not less than 2,500 pounds per square inch (psi) (17 237 kPa) at 28 days.
Where a structure is assigned to Seismic Design Category D in accordance with Section 1613, individual spread footings founded on soil defined in Section 1613.5.2 as Site Class E or F shall be interconnected by ties. Ties shall be capable of carrying, in tension or compression, a force equal to the product of the larger footing load times the seismic coefficient SDS divided by 10 unless it is demonstrated that equivalent restraint is provided by reinforced concrete beams within slabs on grade or reinforced concrete slabs on grade.
The thickness of plain concrete footings supporting walls of other than light-frame construction shall not be less than 8 inches (203 mm) where placed on soil.

Exception: For plain concrete footings supporting Group R-3 occupancies, the thickness is permitted to be 6 inches (152 mm), provided that the footing does not extend beyond a distance greater than the thickness of the footing on either side of the supported wall.
Concrete shallow foundations shall not be placed through water unless a tremie or other method approved by the commissioner is used. Where placed under or in the presence of water, the concrete shall be deposited by approved means to ensure minimum segregation of the mix and negligible turbulence of the water.
No shallow foundation shall be placed on frozen soils unless the soils are maintained in frozen condition throughout the service life of the structure being supported. No foundation shall be placed in freezing weather unless provision is made to maintain the underlying soil free of frost. Concrete shallow foundations shall be protected from freezing during depositing and for a period of not less than five days thereafter. Water shall not be allowed to flow through the deposited concrete.
The design, materials and construction of masonry-unit footings shall comply with the provisions of Chapter 21.
Grillage footings of structural steel shapes shall be separated with approved steel spacers and be entirely encased in concrete with at least 6 inches (152 mm) on the bottom and at least 4 inches (102 mm) at all other points. The spaces between the shapes shall be completely filled with concrete or cement grout.
Refer to Chapter 23.
Refer to Chapter 23.
The design, materials, and construction of pier foundations shall conform to the requirements of Sections 1805.5.2, 1805.5.3, and 1805.5.7.1 through 1805.5.7.6.

Exception: Piers shall be load tested as a deep foundation in accordance with the applicable portions of Section 1808 when the bearing stratum is not physically available for inspection during construction as required by Chapter 17.
The minimum horizontal dimension of piers shall be 2 feet (610 mm), and the height shall not exceed 12 times the least horizontal dimension.
Where adequate lateral support is furnished by the surrounding materials defined in Section 1808.7, piers may be constructed of plain or reinforced concrete and the requirements of ACI 318 shall apply.

Exception: Where adequate lateral support is not provided, and the ratio of unsupported height to least horizontal dimension does not exceed three, piers of plain concrete shall be designed and constructed as pedestals in accordance with ACI 318. Where the unsupported height to least horizontal dimension exceeds three, piers shall be constructed of reinforced concrete, and shall conform to the requirements for columns in ACI 318.
Reinforcement shall be tied and placed as a unit in the pier prior to placement of concrete.

Exception: Steel dowels embedded 5 feet (1524 mm) or less in the pier may be placed individually. Reinforcement is permitted to be wet set and the concrete cover that is otherwise required to measure a minimum of 21/2 inches (64 mm) may be reduced to 2 inches (51 mm) for Groups R-3 and U occupancies not exceeding two stories of light-frame construction, provided the construction method is approved by the commissioner.
Concrete shall be placed in such a manner as to ensure the exclusion of any foreign matter and to fill the full lateral dimensions of each pier. Concrete shall not be placed through water except where a tremie or other approved method is used. When depositing concrete from the top of the pier, the concrete shall not be chuted directly into the pier but shall be poured in a rapid and continuous operation through a funnel hopper centered at the top of the pier.
Where concrete piers are entirely encased within a circular steel shell, and the area of the shell steel is considered reinforcing steel, the steel shall be protected under the conditions specified in Section 1808.2.12. Horizontal joints in the shell shall be spliced to comply with Section 1808.2.11.
Where piers are carried to depths below the groundwater level, the piers shall be constructed by a method that will provide accurate preparation and inspection of the subgrade in dry conditions.
Concrete and masonry foundation walls shall be designed in accordance with Chapter 19 or 21, respectively.
The minimum thickness of concrete and masonry foundation walls shall comply with Section 1805.5.8.1.1.
The thickness of foundation walls shall not be less than the thickness of the wall supported, except that foundation walls of at least 8 inch (203 mm) nominal width are permitted to support brick-veneered frame walls and 10 inch wide (254 mm) cavity walls.
Foundation walls shall be designed to support the weight of the full hydrostatic pressure of undrained backfill unless a drainage system is installed in accordance with Sections 1807.4.2 and 1807.4.3.
For structures assigned to Seismic Design Category C or D, provisions of ACI 318 Section 21.12, as modified by Section 1805 of this code, shall apply when not in conflict with the provisions of Section 1805 of this code. Concrete shall have a specified compressive strength of not less than 3,000 psi (20.68 MPa) at 28 days.

Exceptions:

1. Group R or U occupancies of light-framed construction and two stories or fewer in height are permitted to use concrete with a specified compressive strength of not less than 2,500 psi (17.2 MPa) at 28 days.

2. One and two-family dwellings not more than three stories in height are not required to comply with the provisions of ACI 318, Sections 21.10.1 through 21.10.3.
Retaining walls shall be designed in accordance with Sections 1806.2.
Retaining walls shall be designed to ensure stability against overturning, sliding, excessive foundation pressure and water uplift. Where a keyway is extended below the wall base with the intent to engage passive pressure and enhance sliding stability, lateral soil pressures on both sides of the keyway shall be considered in the sliding analysis.
Retaining walls shall be designed for the lateral soil loads set forth in Section 1605.

Exception: Where the structural design of a retaining wall is based on load factor design, the load factors in Section 1605.2 may be modified as follows: where water can freely flow over the top of the wall, the wall may be designed for a water pressure equal to that caused by a groundwater table elevation at the top of the wall. For this condition, the load factor for the groundwater pressure may be reduced to 1.2. The load factor for the lateral earth pressure shall remain at 1.6.
Retaining walls shall be designed to resist the lateral action of soil to produce sliding and overturning with a minimum safety factor of 1.5 in each case. The load combinations of Section 1605 shall not apply to this requirement. Instead, design shall be based on 0.7 times nominal earthquake loads, 1.0 times other nominal loads, and investigation with one or more of the variable loads set to zero. The safety factor against lateral sliding shall be taken as the available soil resistance at the base of the retaining wall foundation divided by the net lateral force applied to the retaining wall.

Exception: Where earthquake loads are included, the minimum safety factor for retaining wall sliding and overturning shall be 1.1.
Structural members for temporary retaining structures may be designed with a 20 percent decrease in the computed bending moment only.
Walls or portions thereof that retain soil or rock and enclose interior spaces and floors below grade shall be waterproofed or dampproofed in accordance with this section, with the exception of those spaces containing occupancy groups other than residential and institutional where such omission is not detrimental to the building or occupancy. Ventilation for crawl spaces shall comply with Section 1203.3.
Buildings and structures in areas of special flood hazard shall comply with Appendix G.
Where hydrostatic pressure will not occur as determined by Section 1802, floors and walls for other than wood foundation systems shall be dampproofed in accordance with this section. Wood foundation systems shall be constructed in accordance with AF&PA; TR7.
Dampproofing materials for floors shall be installed between: (i) the floor and (ii) the base course required by Section 1807.4.1 or the sub-floor. Subgrade for the dampproofing material shall be prepared in accordance with manufacturer’s recommendations. Dampproofing material shall be installed in accordance with manufacturer’s recommendations, and protected after placement. Any damaged areas and punctures must be repaired prior to placement of slab. All penetrations shall be sealed as per manufacturer’s recommendations.
Dampproofing materials for walls shall be installed on the exterior surface of the wall, and shall extend from the top of the footing to above ground level as determined by the registered design professional and shall be installed in accordance with manufacturer’s recommendations. Dampproofing at walls shall overlap or extend past the slab dampproofing such that there are no gaps or breaches in the dampproofing system.
Where the geotechnical investigation required by Section 1802 indicates that a hydrostatic pressure condition exists, walls and floors shall be waterproofed in accordance with this section.
Floors required to be waterproofed shall be designed and constructed to withstand the hydrostatic pressures to which the floors will be subjected. Waterproofing shall be accomplished by creating a continuous water seal below the floor using appropriate waterproofing materials. Joints, penetrations and other interruptions shall be sealed in accordance with manufacturer’s recommendations. Floor waterproofing must be transitioned to accomplish a complete tie-in with the foundation wall waterproofing.
Walls required to be waterproofed shall be designed and constructed to withstand the hydrostatic pressures and other lateral loads to which the walls will be subjected. Waterproofing shall be applied from the bottom of the wall to not less than 12 inches (305 mm) above the maximum elevation of the groundwater table or as directed by the registered design professional. The remainder of the wall shall be dampproofed in accordance with Section 1807.2.2. Joints, penetrations and other interruptions shall be sealed in accordance with manufacturer’s recommendations.
Joints in or between walls and floors, and penetrations of walls and floors shall be sealed utilizing methods and materials approved by the registered design professional. Joints, penetrations and other interruptions shall be sealed in accordance with the manufacturer’s recommendations.
Where it is determined that there is a potential for infiltration or seepage, a subsoil drainage system shall be permitted to be used to control this inflow, provided that:

1. The below ground space is waterproofed or dampproofed per Sections 1807.2 and 1807.3; and

2. The estimated discharge from the drainage system is less than or equal to the amount allowed by the agency having jurisdiction.
A drainage course shall consist of washed gravel, crushed natural stone or other suitable drainage medium acceptable to the engineer. Recycled concrete aggregate is not acceptable for use in a drainage course where a subsoil drainage system is used.
A foundation drain shall be installed where required by the registered design professional. The foundation drain, including layout, materials, and cleanouts, shall be designed by the registered design professional.
The drainage course and foundation drain shall discharge by gravity or mechanical means into an approved drainage system that complies with the New York City Plumbing Code and any other laws or requirements of agencies having jurisdiction.
In situ walls (such as slurry walls, tangent pile walls, and secant pile walls) with joints sealed by grouting or other methods acceptable to the engineer shall not require waterproofing or dampproofing unless required by the engineer.
Deep foundation elements, including but not limited to piles, caisson piles, and helical piles, shall comply with Section 1808. In addition, driven piles shall comply with Section 1809; cast-in-place concrete piles shall comply with Section 1810; composite piles shall comply with Section 1811; and helical piles shall comply with Section 1812.
Piles shall be designed and installed in accordance with the requirements of the geotechnical investigation and report required by Section 1802 and Sections 1808 through 1812.
Where pile foundations are used, the geotechnical investigation and report provisions of Section 1802 shall be expanded to include, but not be limited to, consideration of the following:

1. Suitable pile types and installed capacities.

2. Suitable center-to-center spacing of deep foundation elements.

3. Driving criteria.

4. Installation procedures.

5. Field inspection and reporting procedures (to include procedures for verification of the installed bearing capacity where required).

6. Pile load test requirements.

7. Durability of pile materials.

8. Designation of bearing stratum or strata.

9. Reductions for group action, where necessary.
Special inspections for deep foundations shall be performed by an engineer in accordance with Sections 1704.8 and 1704.9.
Pile caps shall be of reinforced concrete, and shall include all elements to which piles are connected, including grade beams and mats. The soil immediately below the pile cap shall not be considered as carrying any vertical load. The tops of piles shall be embedded not fewer than 3 inches (76 mm) into pile caps and the caps shall extend at least 4 inches (102 mm) beyond the edges of piles. The tops of piles shall be cut back to sound material before capping. Pile caps shall be protected from the effects of frost in accordance with Section 1805.3.1.
In the conditions described below, the several parts of the building supported on the different pile types or different pile capacities, shall be separated by suitable joints providing for differential movement, or analysis shall be prepared by the engineer, establishing to the satisfaction of the commissioner that the proposed construction is adequate and safe, and showing that the probable settlements and differential settlements to be expected will be tolerable to the structure and not result in instability of the building. The load test requirements of Section 1808.4 shall apply separately and distinctly to each different type or capacity of piling or equipment used, or method of installation, except where analysis of the probable, comparative behavior of the different type or capacity of the piling or the method of installation indicates that data on one type or capacity of piling permit a reliable extrapolation of the probable behavior of the piling of other types or capacities. The requirements of this section apply to the following proposed conditions:

1. Construction of a foundation for a building utilizing piles of more than one type or capacity;

2. Modification of an existing foundation by the addition of piles of a type or capacity other than those of the existing piling;

3. Construction or modification of a foundation utilizing different methods or more than one method of installation, or using different types or capacities of equipment (such as different types of hammers having markedly different striking energies or speeds); or

4. Support of part of a building on piles and part on footings.
The settlement of individual piles or groups of piles shall be estimated based on approved methods of analysis. The predicted settlement shall cause neither harmful distortion of, nor instability in, the structure, nor cause any stresses to exceed allowable values.
Piles left in place where a structure has been demolished shall not be used for the support of new construction unless the piles are load tested, original installation and testing records are available, or the new loads are no more than half the calculated previous loads on the piles. The engineer shall determine and certify that the piles are sound and meet the requirements of this code.
The use of types of piles not specifically mentioned herein is permitted, subject to the approval of the commissioner, upon the submission of acceptable test data, calculations and other information relating to the structural properties and load capacity of such piles. The allowable stresses shall not in any case exceed the limitations specified herein.
Minimum spacing of piles shall: (i) provide for adequate distribution of the load on the pile group into the supporting soil or rock, (ii) account for installation effects, and (iii) be in accordance with Section 1808.2.2.
Piles located near a lot line shall be designed on the assumption that the adjacent lot will be excavated to a depth of 10 feet (3048 mm) below the nearest legally established curb level. Where such excavation would reduce the embedded length of the pile, the portion of the pile exposed shall be deemed to provide no lateral or vertical support, and the load-carrying determination shall discount the resistance offered by the soil that is subject to potential excavation.
Splices shall be constructed so as to provide and maintain true alignment and position of the component parts of the pile during installation and thereafter and shall be of adequate strength to transmit the vertical and lateral loads (including tensions) and the moments occurring in the pile section at the location of the splice without exceeding the allowable stresses for such materials as established in Table 1808.8. In all cases splices shall develop at least 50 percent of the capacity of the pile in bending. In all cases pile splices situated in the upper 10 feet (3048 mm) of the pile shall be capable of resisting (at allowable working stresses) the applied moments and shears. For individual piles or groups comprised of two piles, splices in the upper 10 feet also shall be capable of resisting the moment and shear that would result from an assumed eccentricity of the pile load of 3 inches (76 mm). For piles located near a lot line, the applied moment and shears of such piles shall be determined on the basis that the adjacent site will be excavated to a depth of 10 feet (3048 mm) below the nearest established curb level as required in Section 1808.2.10.

Exception: For caissons core beams, the splice shall develop the lesser of 50 percent of the capacity of the core in bending or twice the design bending moment carried by the core at the location of the splice, provided that the core splice is not within two caisson diameters of any splice in the casing.
Where boring records or site conditions indicate possible deleterious action on pile materials because of soil constituents or other aggressive environmental factors (such as chemical seepage, the presence of salt water, electrical current, changing water levels or other factors), the pile materials shall be adequately protected by materials, methods or processes approved by the engineer. Protective materials shall be applied to the piles so as not to be rendered ineffective by driving. The effectiveness of such protective measures for the particular purpose shall have been thoroughly established by satisfactory service records or other evidence.

Piles installed in ash, garbage, or cinder fills; piles that are free-standing in or near a seawater environment; piles used for the support of chemical plants or coal storage; piles under similar conditions of chemical seepage or aggressive action; and piles that are used for support of electrical generating plants, shall be investigated regarding the need for special protective treatment. Where special protective treatment is indicated by the engineer, such piles shall be protected against deterioration by encasement, coating or other device acceptable to the engineer.
The minimum concrete cover for cast-in-place and precast concrete piles shall be as shown in Table 1808.2.13.

TABLE 1808.2.13 MINIMUM CONCRETE COVER FOR CAST IN PLACE AND PRECAST CONCRETE PILESa

FOUNDATION ELEMENT OR CONDITION MINIMUM COVER
1. Precast nonprestressed deep foundation elements
Exposed to seawater 3 inches
Not manufactured under plant conditions 2 inches
Manufactured under plant control conditions In accordance with
Section 7.7.3 of ACI 318
2. Precast prestressed deep foundation elements
Exposed to seawater 2.5 inches
Other In accordance with
Section 7.7.3 of ACI 318
3. Cast-in-place deep foundation elements not
enclosed by a steel pipe, tube or permanent
casing
2.5 inches
4. Cast-in-place deep foundation elements enclosed
by a steel pipe, tube or permanent casing
1 inch
5. Structural steel core within a steel pipe, tube or
permanent casing
2 inches
6. Cast-in-place drilled shafts enclosed by a stable
rock socket
1.5 inches

For SI: 1 inch = 25.4 mm.
a. The concrete cover provided for prestressed and nonprestressed reinforcement in foundations shall be no less than the largest applicable value specified in Table 1808.2.13. Longitudinal bars spaced less than 11/2 inches (38 mm) clear distance apart shall be considered bundled bars for which the concrete cover provided shall also be no less than that required by Section 7.7.4 of ACI 318. Concrete cover shall be measured from the concrete surface to the outermost surface of the steel to which the cover requirement applies. Where concrete is placed in a temporary or permanent casing or a mandrel, the inside face of the casing or mandrel shall be considered the concrete surface.
Allowable pile loads shall be determined in accordance with Sections 1808.3.1 through 1808.3.5.
The allowable individual axial compressive loads on piles shall be the lesser of the allowable structural capacity of the element and the allowable geotechnical capacity of the element. This allowable load shall be determined by an engineer experienced in geotechnical engineering and shall be approved by the commissioner as described below:

1. The allowable structural capacity of the pile shall be determined in accordance with Sections 1808 through 1813 of this code.

2. The allowable geotechnical capacity of the pile shall be calculated using a recognized method of analysis, and a minimum factor of safety of 2 with respect to failure.

3. The allowable geotechnical capacity shall be demonstrated by load tests.

Exceptions:

1. Allowable loads for piles installed by jacking shall be determined in accordance with Section 1808.3.2.

2. Caissons socketed into Class 1a through 1c material as defined in Table 1804.1.

3. Driven piles with allowable loads less than or equal to 40 tons (30 tons for timber piles).

4. Micropiles with allowable loads less than or equal to 20 tons, provided all of the following criteria are satisfied:

4.1. The maximum allowable bond stress between the soil and the grout is less than or equal to 4 psi.

4.2. The minimum bond zone diameter is greater than or equal to 9 inches (228.6 mm).

4.3. The bond zone is formed entirely in Class 3b or better soils.
The allowable load determined in Section 1808.3.1 shall account for pile group effects. The analysis of group effects shall be performed by an engineer experienced in geotechnical engineering and calculated using recognized methods of analysis. This analysis shall include a bearing capacity and settlement analysis of the anticipated pile groups and shall consider the presence of weaker soil strata that may be present below the element.
Where piles are installed through subsiding fills or other subsiding strata and derive support from underlying firmer materials, consideration shall be given to the downward frictional forces that may be imposed on the piles by the subsiding upper strata.
The plans for the proposed work shall establish, in accordance with the requirements relating to allowable bearing pressure, the bearing stratum to which the piles in the various sections of the building must penetrate and the approximate elevations of the top of such bearing stratum. Where penetration of a given distance into the bearing strata is required for adequate distribution of the loads, such penetration shall be shown on the plans. The indicated elevations of the top of the bearing strata shall be modified by such additional data as may be obtained during construction. All piles shall penetrate to or into the designated bearing stratum.
The allowable capacity of a pile installed by jacking or other static forces shall be not more than 50 percent of the load or force used to install the pile to the required penetration, except for piles jacked into position for underpinning. The allowable capacity of each permanent underpinning pile shall not exceed the larger of the following values: 2/3 of the total jacking force used to obtain the required penetration if the load is held constant for 7 hours without measurable settlement; or 1/2 of the total jacking force at final penetration if the load is held for a period of 1 hour without measurable settlement. The jacking resistance used to determine the working load shall not include the resistance offered by nonbearing soils, soils which are to be excavated or soils where support will dissipate with time.
The allowable axial compressive load for helical piles shall be in accordance with the requirements of Section 1812.
Where required by the design, the allowable uplift load for a single pile shall be determined in accordance with accepted engineering practices based on a minimum factor of safety of three or by uplift load tests performed in accordance with Section 1808.4.2.1. Where uplift load tests are performed, the maximum allowable uplift load shall not exceed the ultimate load capacity divided by a factor of safety of two. The allowable uplift load for a pile group shall not exceed the sum of the allowable uplift loads of the individual piles in the group, nor the uplift capacity calculating the group action of the pile in accordance with accepted engineering practice where the calculated ultimate group capacity is divided by a safety factor of 2.5.
The allowable lateral load of a single pile or a pile group shall be determined by an approved method of analysis in accordance with accepted engineering practice. The maximum allowable lateral load of a pile shall be 1 ton (8.9 kN), unless verified by lateral load test. Load testing, where required, shall be in accordance with Section 1808.4.3. See Sections 1808.4.3.1 and 1808.4.3.2 for determining the allowable lateral load from the results of lateral load tests.
Lateral capacities for pile groups shall be modified to account for group effects in accordance with accepted engineering practice.
Where required, piles shall be load tested in accordance with the requirements of Sections 1808.4.1 through 1808.4.3.
Where load tests are required per Section 1808.3 or 1808.4.1.1.1, the piles shall be load tested in accordance with the applicable section.
Where load tests are required, at least one test shall be performed in each area of the foundation site within which the subsurface soil conditions are "substantially similar" in character, as determined by the engineer, and at least one test shall be performed for each pile type for the entire foundation installation of the building or group of buildings on a site occupying a total area of 5,000 square feet (465 m2) or less. Where load tests are required, at least two load tests shall be performed for a site having a footprint between 5,000 square feet (465 m2) and 30,000 square feet (2787 m2), and one additional load test shall be performed for each 20,000 square feet (1860 m2) of added footprint area. For conditions where multiple pile types or capacities are used, refer to Section 1808.2.5.
Where installed pile capacities are in doubt, the piles are considered non-conforming by the engineer, or as required by the commissioner, additional piles shall be load tested to establish the allowable capacity. For friction piles where the actual production pile lengths vary more than 25 percent from that of the test pile, the engineer shall determine if additional load tests are required to establish the allowable pile capacity. The number of additional load tests shall be determined by the engineer or commissioner.
The apparatus and structure to be used in making the load test shall be designed by an engineer. Load tests shall be performed under the observation of the special inspector. A complete record of such tests shall be filed with the commissioner.
Compressive load tests shall be conducted in accordance with ASTM D 1143 standard procedures and the following conditions:

1. Dial extensometer gages shall provide readings to the nearest 0.001 inch (0.025 mm). Electrical transducers may be used to make settlement observations, provided that backup measurements are made utilizing dial extensometers as described herein at sufficient times to validate the transducer readings.

2. If the allowable axial compressive load is less than or equal to the Basic Maximum Allowable Pile Load in Table 1808.4.1.3, the total test load shall remain in place for a minimum of 12 hours, and shall be held until the average rate of settlement as measured over a 12-hour period does not exceed 0.001 inches (0.025 mm) per hour. The total load shall be removed in decrements not exceeding 25 percent of the total load at 1 hour intervals or longer. For cases where the allowable pile load is greater than the values prescribed in Table 1808.4.1.3, refer to Section 1808.4.1.5.

3. In addition to observations required by ASTM D 1143, settlement observations shall be performed 24 hours after the entire test load has been removed.

Exception: A static load test for drilled piles using an embedding load transfer mechanism shall be considered acceptable, provided that the test is performed in general accordance with ASTM D 1143 – Quick Load Test Method. The pile shall be suitably instrumented to evaluate the load transfer through soil or rock at multiple locations along the shaft.

4. Any temporary supporting capacity that the soil might provide to the pile during a load test, but which would be dissipated with time, shall be eliminated by casing off or by other suitable means, such as increasing the total test load to account for such temporary capacity.

TABLE 1808.4.1.3 BASIC MAXIMUM ALLOWABLE PILE LOADS

TYPE OF PILE MAXIMUM ALLOWABLE PILE LOAD (TONS)
Caisson Piles No upper limit
Open-end pipe (or tube) piles bearing on rock of Class 1a, 1b, or 1c 18-in O.D. and greater 250
14-in to 18-in O.D. 200
12-in to 14-in O.D. 150
10-in to 12-in O.D. 100
8-in to 10-in O.D. 60
Closed-end pipe (or tube) piles, H-piles, cast-in-place concrete, enlarged base piles, and precast concrete piles bearing on rock of Class 1a, 1b, or 1c 150
Piles (other than timber or helical piles) bearing on soft rock of Class 1d 80
Piles (other than timber or helical piles) that receive their principal support other than by direct bearing on rock of Class 1a through 1d 75
Timber piles bearing on rock of Class 1a through 1d 25
Timber piles bearing in suitable soils 40 tons maximum permissible
with load test, 30 tons maximum
without load test.
Helical piles 30 tons maximum permissible

For SI: 1 ton = 907.18 kg.
High strain, dynamic compressive test methods performed in accordance with ASTM D 4945 shall be permitted to be used where three or more load tests are required and subject to the approval of the commissioner. In such case, at least one high strain dynamic test shall be performed as a calibration on a static load tested pile or nearby pile driven to comparable resistance. No more than one-half of the required number of load tests may be performed by high strain dynamic methods. High strain dynamic tests shall be performed under the supervision of an engineer experienced in the methods used. The number of high strain dynamic tests shall be at least twice the number of replaced static load tests.
The allowable pile load shall be the lesser of the two values computed as follows:

1. Fifty percent of the applied load causing a net settlement of the pile of not more than 1/100 of 1 inch per ton (0.25 mm per 8.9 kN) of applied load. Net settlement in this paragraph is defined as gross settlement due to the total test load minus the rebound after removing 100 percent of the test load.

2. Fifty percent of the applied load causing a net settlement of the pile of 3/4 inch (19 mm). Net settlement in this paragraph is defined as the gross settlement due to the total test load less the amount of elastic shortening in the pile section due to total test load. The elastic shortening shall be calculated as if the pile is designed as an end-bearing pile or as a friction pile. Alternatively, the net settlement may be measured directly using a telltale or other suitable instrumentation.
The basic maximum allowable pile loads tabulated in Table 1808.4.1.3 may be exceeded where a higher value can be substantiated on the basis of load tests and analysis, except for the loads for timber and helical piles. The provisions of Section 1808.4.1 shall be supplemented, as follows: the final load increment shall remain in place for a total of not less than 24 hours; single test piles shall be subjected to cyclical loading or suitably instrumented with telltales and strain gauges so that the movements of the pile tip and butt may be independently determined and load transfer to the soil evaluated. A complete record demonstrating satisfactory performance of the test shall be submitted to the commissioner.
Where uplift load tests are required, one uplift load test shall be conducted in each area of substantially similar subsurface conditions up to 5,000 square feet (465 m2) of building footprint where piles are subjected to uplift, and not less than two uplift load tests shall be conducted for each area of building footprint where piles are subjected to uplift between 5,000 square feet (465 m2) and 30,000 square feet (2787 m2) and for such area one additional upload load test shall be conducted for each 20,000 square feet (1860 m2) of additional area of building footprint where piles are subject to uplift. For conditions where multiple pile types or capacities are used, refer to Section 1808.2.5.
Uplift load tests shall be conducted in accordance with ASTM D 3689 standard procedures and the following conditions:

1. Dial extensometer gages shall provide readings to the nearest 0.001 inch (0.025 mm). Electrical transducers may be used to make settlement observations provided that backup measurements are made utilizing dial extensometers as described herein at sufficient times to validate the transducer readings.

2. Any temporary supporting capacity that the soil might provide to the pile during a load test, but which would be dissipated with time, shall be eliminated by casing off or by other suitable means, such as increasing the total test load to account for such temporary capacity.
The apparatus and structure to be used in making the load test shall be designed by an engineer. Load tests shall be performed under the observation of the special inspector. A complete record of such tests shall be filed with the commissioner.
Where testing is required, lateral load tests shall be performed in accordance with ASTM D 3966. A minimum of two piles shall be tested for every area of similar subsurface conditions. For conditions where multiple pile types or capacities are used, refer to Section 1808.2.5.
For piles whose heads are to be designed to be free to rotate in the final structure, the maximum test load shall be at least twice the proposed design working load. In the absence of specific project requirements as determined by the engineer, the resulting allowable load shall not be more than one-half of that test load that produces a gross lateral movement of 1 inch (25 mm) at the ground surface.
For piles whose heads are designed to be fixed in the final structure, the results of the load test shall be used to verify the input parameters used in the lateral load analysis. In the absence of specific project requirements as determined by the engineer, the allowable load shall be the load that produces a gross lateral movement of 3/8 of an inch at the ground surface in the lateral load analysis.
Lateral load tests shall be conducted in accordance with ASTM D 3966 standard procedures. In addition, dial extensometer gages shall provide readings to the nearest 0.001 inch (0.025 mm). Electrical transducers may be used to make deflection observations, provided that backup measurements are made utilizing dial extensometers as described herein at sufficient times to validate the transducer readings.
The apparatus and structure to be used in making the load test shall be designed by an engineer. Lateral load tests shall be performed under the observation of the special inspector. A complete record of such tests shall be filed with the commissioner.
Installation of piles shall be subject to the requirements of Sections 1808.5.1 through 1808.5.8.
Piling shall be handled and installed to the required penetration and resistance by methods that leave the piles’ strength unimpaired and that develop and retain the piles’ required load-bearing resistance. Any damaged pile shall be satisfactorily repaired or the pile shall be rejected. As an alternative and subject to the approval by the commissioner, damaged or misaligned piles or piles not reaching design tip elevation may be used at a reduced fraction of the design load based on an analysis by the engineer.
Equipment and methods of installation shall be such that piles are installed in their proper position and alignment, without damage. Equipment shall be maintained in good working order.
The use of jetting, augering or other methods of preexcavation shall be subject to the approval of the commissioner. Where permitted, preexcavation shall be carried out in the same manner as used for piles subject to load tests and in such a manner that will not impair the carrying capacity of the piles already in place or damage adjacent structures. Pile tips shall be driven below the preexcavated depth until the required resistance or penetration is obtained.
Piles shall penetrate the minimum distance required to develop the required load capacity of the pile as established by the required penetration resistance and load tests as applicable.
Piles shall be installed in such a manner and sequence as to prevent distortion or damage that affects the structural integrity of the piles being installed, or previously installed adjacent piles. The sequence of the installation shall avoid compacting the surrounding soil to the extent that other piles cannot be installed properly, and shall prevent ground movements that are capable of damaging adjacent structures. Piles shall be installed with adequate provision for the protection of adjacent buildings and property.
All pile materials shipped or delivered to the job site shall be identified for conformity to the specified grade and this identification shall be maintained continuously from the point of manufacture to the point of installation. Such shipment or delivery shall be accompanied by a certification from the material supplier or manufacturer indicating conformance with the construction documents. Such certification shall be made available to the engineer of record and the department. In the absence of adequate data, pile materials shall be tested by an approved agency to determine conformity to the specified grade. The approved agency shall furnish a certification of compliance to the engineer of record, or upon request to the commissioner.
A plan showing the location and designation of piles by an identification system shall be filed with the commissioner prior to installation of such piles. Detailed records for individual piles shall bear an identification corresponding to that shown on the plan.
Piles within the area of influence of a given, satisfactorily tested pile shall be installed to the same installation criteria as the successful test pile. The same equipment that was used to install the test pile, identically operated in all aspects, shall be used to install the piles. All piles shall be of the same type, size and shape as the test pile. All piles within the area of influence as represented by a given satisfactorily tested test pile shall bear in, or on, the same bearing stratum as the test pile.
Tolerances for piles shall be in accordance with the requirements of Sections 1808.6.1 through 1808.6.4.
A tolerance of 3 inches (76 mm) from the designed location shall be permitted in the installation of each pile as measured from the pile head, without reduction in load capacity of the pile group unless otherwise noted on the foundation plans. When piles are installed outside of this tolerance, the true loading on such piles shall be analytically determined from a survey that defines the actual location of the piles as installed and using the actual eccentricity in the pile group with respect to the line of action of the applied load.
If the axis of any pile is installed out of plumb or deviates from the specified batter by more than 4 percent, the design of the foundation shall be modified to resist the resulting vertical and lateral forces. In types of piles for which subsurface inspection is not possible, this determination shall be made on the exposed section of the pile, which section, at the time of checking axial alignment, shall not be less than 2 feet (610 mm) in length. In piles that can be checked for axial alignment below the ground surface, the sweep of the pile axis shall not exceed 4 percent of the embedded length.
The load-bearing capacity of piles discovered to have a sharp or sweeping bend shall be determined using an approved method of analysis by the engineer responsible for the pile design in accordance with accepted engineering practice or by load testing a representative pile.
The maximum compressive load on any pile due to mislocation shall not exceed 110 percent of the allowable design load. If the total load on any pile, so determined, is in excess of 110 percent of the allowable load-bearing capacity, correction shall be made by installing additional piles or by other methods of load distribution as required to reduce the maximum pile load to 110 percent of the allowable pile capacity.
Lateral support for piles shall be in accordance with the requirements of Sections 1808.7.1 through 1808.7.4.
Any soil other than soil with no shear strength shall be deemed to afford sufficient lateral support to the pile to prevent buckling and to permit the design of the pile in accordance with accepted engineering practice and the applicable provisions of this code.
Piles standing unbraced in air, water or soils with no shear strength shall be designed as columns in accordance with the provisions of this code. Such piles driven into firm ground can be considered fixed and laterally supported at 5 feet (1524 mm) below the ground surface and in soft material at 10 feet (3048 mm) below the ground surface unless otherwise prescribed by the engineer.
Piles shall be braced to provide lateral stability and resist eccentric loads and moments in all directions. Three or more piles connected by a rigid cap shall be considered braced, provided that the piles are located in radial directions from the centroid of the group not less than 60 degrees (1 rad) apart. A two-pile group in a rigid cap shall be considered to be braced along the axis connecting the two piles. Methods used to brace piles shall be subject to the approval of the commissioner.

Piles supporting walls shall be driven alternately in lines spaced at least 1 foot (305 mm) apart and located symmetrically under the center of gravity of the wall load carried, unless effective measures are taken to provide for eccentricity and moments due to lateral forces, or the wall piles are adequately braced. A single row of piles without bracing is permitted for one and two-family dwellings and lightweight construction not exceeding two stories or 35 feet (10 668 mm) in height, provided the centers of the piles are located within the width of the wall.
All pile caps supported by piles that penetrate less than ten feet below cutoff level or less than ten feet below ground level shall be braced against lateral movement. Such bracing may consist of connection to other pile caps that encompass piles embedded more than ten feet below those levels. The heads of the piles shall be fixed in the cap. In no case shall more than fifty percent of the piles in the foundation of any building penetrate less than ten feet below cut-off level or less than ten feet below ground level.

Exception: The requirements of this section shall not apply to caisson piles.
Where the embedded length of piles located near a lot line would be reduced to less than ten feet by excavation of the adjacent site to a depth of ten feet below the nearest established curb level, the provisions of Section 1808.7.4 shall apply.
Allowable stresses for piles shall be as listed in Table 1808.8.

TABLE 1808.8 ALLOWABLE STRESSES FOR MATERIALS USED IN PILES

MATERIAL TYPE AND CONDITION MAXIMUM ALLOWABLE STRESSa
1. Concrete or grout in compressionb
Cast-in-place with a permanent casing in accordance with Section 1810.5.2 0.4 fc
Cast-in-place in a pipe, tube, other permanent casing or rock 0.33 f'c
Cast-in-place without a permanent casing 0.3f'c
Precast nonprestressed 0.33 f c
Precast prestressed 0.33 fc – 0.27 fpc
2. Nonprestressed reinforcement in compression 0.4 fy ≤ 30,000 psi
3. Structural steel in compression
Cores within concrete-filled pipes or tubes 0.5 Fy ≤ 32,000 psi
Pipes, tubes or H-piles, where justified in accordance with Section 1808.2.10 0.5 Fy ≤ 32,000 psi
Pipes or tubes for micropiles 0.4 Fy ≤ 32,000 psi
Other pipes, tubes or H-piles 0.35 Fy ≤ 16,000 psi
Helical piles 0.6Fy ≤ 0.5Fu
4. Nonprestressed reinforcement in tension
Within micropiles or caissons less than 14 inches in diameter 0.6 fy
Other conditions 0.5 fy ≤ 24,000 psi
5. Structural steel in tension
Structural steel cores in caisson piles, 0.5 Fy ≤ 32,000 psi
Pipes, tubes or H-piles, where justified in accordance with Section 1808.2.10 0.5 Fy ≤ 32,000 psi
Other pipes, tubes or H-piles 0.35 Fy ≤ 16,000 psi
Helical piles 0.6 Fy ≤ 0.5Fu
6. Timber See Section 1809.5.4

For SI: 1 pound per square inch = 6.895 kPa.
a. f 'c is the specified compressive strength of the concrete or grout; fpc is the compressive stress on the gross concrete section due to effective prestress forces only; fy is the specified yield strength of reinforcement; Fy is the specified minimum yield stress of structural steel; Fu is the specified minimum tensile stress of structural steel.
b. The stresses specified apply to the gross cross-sectional area within the concrete surface. Where a temporary or permanent casing is used, the inside face of the casing shall be considered the concrete surface.
Allowable stresses for designing piles shall be as specified in Table 1808.8.

Exception: Allowable stresses greater than those specified in Table 1808.8 in Sections 1809 and 1810 shall be permitted where supporting data justifying such higher stresses are filed and approved by the commissioner.
Seismic design of piles shall be performed in accordance with Sections 1808.9.1 through 1808.9.3.
Where a structure is assigned to Seismic Design Category C in accordance with Section 1613, individual pile caps or piles shall be interconnected by ties. Ties shall be capable of carrying, in tension and compression, a force equal to the lesser of: (i) the product of the larger of the pile cap or column design gravity load times the seismic coefficient, SDS, divided by 10, or (ii) 25 percent of the smaller of the pile or column design gravity load, unless it can be demonstrated that equivalent restraint is provided by reinforced concrete beams within slabs on grade, reinforced concrete slabs on grade, or confinement by competent rock, hard cohesive soils or very dense granular soils.
For structures assigned to Seismic Design Category C or D in accordance with Section 1613, concrete deep foundation elements shall be connected to the pile cap by embedding the element reinforcement or field-placed dowels anchored in the element into the pile cap for a distance equal to their development length in accordance with ACI 318. It shall be permitted to connect precast, prestressed piles to the pile cap by developing the element prestressing strands into the pile cap, provided the connection is ductile. For deformed bars, the development length is the full development length for compression, or tension in the case of uplift, without reduction for excess reinforcement in accordance with Section 12.2.5 of ACI 318. Alternative measures for laterally confining concrete and maintaining toughness and ductile-like behavior at the top of the element shall be permitted, provided the design is such that any hinging occurs in the confined region. The minimum transverse steel ratio for confinement shall not be less than one-half of that required for columns.

For resistance to uplift forces, anchorage of steel pipes, tubes or H-piles to the pile cap shall be made by means other than concrete bond to the bare steel section. Concrete-filled steel pipes or tubes shall have reinforcement of not less than 0.01 times the cross sectional area of the concrete fill, developed into the cap and extending into the concrete fill a length equal to two times the required cap embedment, but not less than the development length in tension of the reinforcement.

Exception: Anchorage of concrete-filled steel pipe piles is permitted to be accomplished using deformed bars developed into the concrete portion of the pile. Splices of pile segments shall develop the full strength of the pile, but the splice need not develop the nominal strength of the pile in tension, shear and bending when the splice has been designed to resist axial and shear forces and moments from the load combinations of Section 12.4 of ASCE 7-10.
Pile moments, shears and lateral deflections used for design shall be established considering the nonlinear interaction of the shaft and soil, as recommended by the engineer. Where the ratio of the depth of embedment of the pile-to-pile diameter or width is less than or equal to six, the pile may be assumed to be rigid. Pile group effects from soil on lateral pile nominal strength shall be included where pile center-to-center spacing in the direction of lateral force is less than eight pile diameters. Pile group effects on vertical nominal strength shall be included where pile center-to-center spacing is less than three pile diameters. The pile uplift soil nominal strength shall be taken as the pile uplift strength as limited by the frictional force developed between the soil and the pile.

Where a minimum length for reinforcement or the extent of closely spaced confinement reinforcement is specified at the top of the pile, provisions shall be made so that those specified lengths or extents are maintained after pile cutoff.
Where a structure is assigned to Seismic Design Category D in accordance with Section 1613, the requirements for Seismic Design Category C given in Section 1808.9.2 shall be met. Provisions of ACI 318, Section 21.12.4, shall also apply when not in conflict with the provisions of Sections 1808 through 1813. Concrete shall have a specified compressive strength of not less than 3,000 psi (20.68 MPa) at 28 days.

Exceptions:

1. Group R or U occupancies of light-framed construction and two stories or less in height are permitted to use concrete with a specified compressive strength of not less than 2,500 psi (17.2 MPa) at 28 days.

2. Detached one and two-family dwellings of light-frame construction and two stories or less in height are not required to comply with the provisions of ACI 318, Section 21.12.4.

3. Section 21.12.4.4(a) of ACI 318 shall not apply to concrete piles.
Piles shall be designed and constructed to withstand maximum imposed curvatures from earthquake ground motions and structure response. Curvatures shall include free-field soil strains modified for soil-pile-structure interaction coupled with pile deformations induced by lateral pile resistance to structure seismic forces. Concrete piles on Site Class E or F sites, as determined in Section 1613.5.2, shall be designed and detailed in accordance with Sections 21.12.4.1, 21.12.4.2 and 21.12.4.3 of ACI 318 within seven pile diameters of the pile cap and the interfaces of soft to medium stiff clay or liquefiable strata. For precast prestressed concrete piles, detailing provisions as given in Sections 1809.6.3.2.1 and 1809.6.3.2.2 shall apply. Grade beams shall be designed as beams in accordance with ACI 318, Chapter 21. When grade beams have the capacity to resist the forces from the load combinations in Section 1605.4, they need not conform to ACI 318, Chapter 21.
For piles required to resist uplift forces or provide rotational restraint, design of anchorage of piles into the pile cap shall be provided considering the combined effect of axial forces due to uplift and bending moments due to fixity to the pile cap. Anchorage into the pile cap shall be capable of developing the following:

1. In the case of uplift, the lesser of the nominal tensile strength of the longitudinal reinforcement in a concrete pile, or the nominal tensile strength of a steel pile, or the pile uplift soil nominal strength factored by 1.3 or the axial tension force resulting from the load combinations of Section 12.4 of ASCE 7-10.

2. In the case of rotational restraint, the lesser of the axial and shear forces, and moments resulting from the load combinations of Section 12.4 of ASCE 7-10 or development of the full axial, bending and shear nominal strength of the pile.
Where the vertical, lateral-force-resisting elements are columns, the grade beam or pile cap flexural strengths shall exceed the column flexural strength.
The connection between batter piles and grade beams or pile caps shall be designed to resist the nominal strength of the pile acting as a short column. Batter piles and their connections shall be capable of resisting forces and moments from the load combinations of Section 12.4 of ASCE 7-10.
Driven piles shall be designed and installed in accordance with Sections 1808 and 1809.2 through 1809.7.
Equipment and methods of installation shall be such that piles are installed in their proper position and alignment, without damage. Equipment shall be maintained in good working order.
The hammer to be used to drive piles shall deliver a maximum energy consistent with the size, strength and weight of the driven piles. The pile-driving hammer shall travel freely in the leads. The hammer shall deliver its rated energy, and measurements shall be made of the fall of the ram or other suitable data shall be obtained at intervals necessary to verify the actual energy delivered during the final 20 blows of the hammer.
The cushion or cap block shall be a solid block of hardwood with its grains parallel to the axis of the pile and enclosed in a tight-fitting steel housing, or other accepted equivalent assembly. If laminated materials are used, their type and construction shall be such that their strength is equal to or greater than hardwood. Wood chips, pieces of rope, hose, shavings, automobile tires or similar materials shall not be used. Cap block cushions shall be replaced if burned, crushed, or otherwise damaged. Other cushion materials may be used subject to the approval of the engineer. The introduction of fresh hammer cushion or pile cushion material just prior to final penetration is not permitted.
Followers shall not be used unless permitted in writing by the engineer responsible for the pile driving operation. The required driving resistance shall account for the losses of driving energy transmitted to the pile because of the follower. The follower shall be a single length section, be provided with a socket or hood carefully fitted to the top of the pile to minimize loss of energy and to prevent damage to the pile, and have sufficient rigidity to prevent "whip" during driving.
The allowable compressive load on steel and concrete piles, where determined solely by the application of an approved wave equation analyses approved by the engineer, shall not exceed 40 tons (356 kN). The allowable compressive loads on timber piles, where determined solely by the wave equation analyses approved by the engineer, shall not exceed 30 tons (267 kN). For allowable loads greater than these values, the wave equation method of analysis may be used to establish initial driving criteria, but final driving criteria and the allowable load shall be verified by load tests in accordance with Section 1808.4. Minimum driving resistance and hammer energy may be determined in accordance with Tables 1809.3(a) and 1809.3(b).

TABLE 1809.3(a) MINIMUM DRIVING RESISTANCE AND MINIMUM HAMMER ENERGY FOR STEEL H-PILES, PIPE PILES, PRECAST AND CAST-IN-PLACE CONCRETE PILES AND COMPOSITE PILES (other than timber)

MINIMUM DRIVING RESISTANCE a, c, d, e
Pile Capacity
(tons)
Hammer Energyb
(ft. lbs.)
Friction Piles
(blows/ft.)
Piles Bearing on Soft Rock
(Class 1d) (blows/ft.)
Piles Bearing on Rock
(Class 1a, 1b, and 1c)
Up to 20 15,000 19 48 5 Blows per 1/4 inch
(Minimum hammer energy
of 15,000 ft. lbs.)
19,000 15 27
24,000 11 16
30 15,000 30 72
19,000 23 40
24,000 18 26
40 15,000 44 96
19,000 32 53
24,000 24 34
> 40 AS PER SECTION 1809.3

For SI: 1 foot = 304.8 mm, 1 ton = 907.18 kg.
a. Final driving resistance shall be the sum of tabulated values plus resistance exerted by nonbearing materials. The driving resistance of nonbearing materials shall be taken as the resistance experienced by the pile during driving, but which will be dissipated with time and may be approximated as described in Section 1809.3.
b. The hammer energy indicated is the rated energy.
c. Sustained driving resistance. Where piles are to bear in soft rock, the minimum driving resistance shall be maintained for the last 6 inches, unless a higher sustained driving resistance requirement is established by load test. Where piles are to bear in soil Classes 2 through 5, the minimum driving resistance shall be maintained for the last twelve inches unless load testing demonstrates a requirement for higher sustained driving resistance. No pile needs to be driven to a resistance that penetrates in blows per inch (blows per 25 mm) more than twice the resistance indicated in this table, nor beyond the point at which there is no measurable net penetration under the hammer blow.
d. The tabulated values assume that the ratio of total weight of pile to weight of striking part of the hammer does not exceed 3.5. If a larger ratio is to be used, or for other conditions for which no values are tabulated, the driving resistance shall be as approved by the commissioner.
e. For intermediate values of pile capacity, minimum requirements for driving resistance may be determined by straight line interpolation.


TABLE 1809.3(b) MINIMUM DRIVING RESISTANCE AND HAMMER ENERGY FOR TIMBER PILES

PILE CAPACITY
(TONS)
MINIMUM DRIVING RESISTANCE (BLOWS/in.) TO BE ADDED TO
DRIVING RESISTANCE EXERTED BY NONBEARING MATERIALS
(NOTES 1, 3, 4)
HAMMER ENERGY
(ft./lbs.) (Note 2)
Up to 20 Formula in Note 4 shall apply 7,500–12,000
Over 20 to 25 9,000–12,000
14,000–16,000
Over 25 to 30 12,000–16,000
(single-acting hammers)
Greater than 30 15,000–20,000
(double-acting hammers)

For SI: 1 ton = 907.18 kg, 1 inch = 25.4 mm.
Notes:
1. The driving resistance exerted by nonbearing materials is the resistance experienced by the pile during driving, but which will be dissipated with time and may be approximated as described in Section 1809.3.
2. The hammer energy indicated is the rated energy.
3. Sustained driving resistance. Where piles are to bear in soft rock, the minimum driving resistance shall be maintained for the last 6 inches (152.4 mm), unless a higher sustained driving resistance requirement is established by load test. Where piles are to bear in soil Classes 2 through 5, the minimum driving resistance measured in blows per inch (blows per 25 mm) shall be maintained for the last 12 inches unless load testing demonstrates a requirement for higher sustained driving resistance. No pile need be driven to a resistance that penetrates in blows per inch (blows per 25 mm) more than twice the resistance indicated in this table nor beyond the point at which there is no measurable net penetration under the hammer blow.
4. The minimum driving resistance shall be determined by the following formula:

P = 2WhH or P = 2E
(S + 0.l) (S + 0.l)

where:

P = Allowable pile load in pounds.
Wp = Weight of pile in pounds.
Wh = Weight of striking part of hammer in pounds.
H = Actual height of fall of striking part of hammer in feet.
E = Rated energy delivered by the hammer per blow in foot/lbs.
S = Penetration of pile per blow, in inches, after the pile has been driven to a depth where successive blows produce approximately equal net penetration.
The value Wp shall not exceed three times Wh.
Where subsurface investigation and general experience in the area indicate that the soil that must be penetrated by the pile consists of glacial deposits containing boulders, or fills containing rip-rap, excavated detritus, masonry, concrete or other obstructions in sufficient numbers to present a hazard to the installation of the piles, the selection of type of pile and penetration criteria shall be subject to the approval of the commissioner, but in no case shall the minimum penetration resistance be less than that stated in Tables 1809.3(a) and 1809.3(b).
Driven piles shall be installed in accordance with Section 1808.2.6 and Sections 1809.4.1 through 1809.4.3.
Piles shall not be driven adjacent to fresh concrete that is less than 3 days old without approval by the engineer.
Piles that have heaved during the driving of adjacent piles shall be redriven as necessary to develop the required capacity and penetration, or the capacity of the pile shall be verified by load tests in accordance with Section 1808.4.
Vibratory drivers shall only be used to install piles where the pile is subsequently seated by an impact hammer to the final driving criteria established in accordance with Section 1809.3.
Timber piles shall be designed in accordance with the AF&PA; NDS.
Round timber piles shall conform to ASTM D 25. Sawn timber piles shall conform to DOC PS-20.
Timber piles used to support permanent structures shall be treated in accordance with this section unless it is established that the tops of the untreated timber piles will be below the lowest groundwater level assumed to exist during the life of the structure as specified in Section 1808.2.12. Preservative and minimum final retention shall be in accordance with AWPA C3 for round timber piles and AWPA C24 for sawn timber piles. Preservative-treated timber piles shall be subject to a quality control program administered by an approved agency. Pile cuts shall be treated in accordance with AWPA M4.
Any sudden decrease in driving resistance of a timber pile shall be investigated with regard to the possibility of damage. If the sudden decrease in driving resistance cannot be correlated to load-bearing data, the pile shall be removed for inspection, or rejected.
Piles shall be of adequate size to resist the applied loads without creating stresses in the pile material in excess of 1,200 psi (8.27 MPa) for piles of southern pine, Douglas fir, oak, or other wood of comparable strength; or 800 psi (5.52 MPa) for piles of cedar, Norway pine, spruce or other wood of comparable strength. Piles of 25 tons (222.5 kN) of capacity or more shall have a minimum 8-inch tip (203 mm) with uniform taper. Piles of less than 25 tons (222.5 kN) of capacity shall have a minimum 6-inch (152 mm) tip with uniform taper. All piles, regardless of capacity, driven to end bearing on bedrock of Classes 1a to 1d and compact gravels and sands of Class 2a shall have a minimum 8-inch (203 mm) tip and a uniform taper. Any species of wood may be used that conforms to ASTM D 25 and that will stand the driving stresses.
The use of lagged or inverted piles is permitted. Double lagging shall be adequately connected to the basic pile material to transfer the full pile load from the basic pile material to the lagging without exceeding values of allowable stress as established in Chapter 23. The connection for single lagging shall be proportioned for half the pile load. The diameter of any inverted pile at any section shall be adequate to resist the applied load without exceeding the stresses specified in Section 1809.5.4, but in no case shall it be less than 8 inches (203 mm).
The materials, reinforcement and installation of precast concrete piles shall conform to Sections 1809.6.1.1 through 1809.6.1.4.
Piles shall be designed and manufactured in accordance with accepted engineering practice to resist all stresses induced by handling, driving and service loads.
The minimum horizontal dimension shall be 8 inches (203 mm). Corners of square piles shall be chamfered.
Longitudinal steel shall be arranged in a symmetrical pattern and be laterally tied with steel ties or wire spiral spaced not more than 4 inches (102 mm) apart, center to center, for a distance of 2 feet (610 mm) from the ends of the pile; and not more than 6 inches (152 mm) elsewhere except that at the ends of each pile, the first five ties or spirals shall be spaced 1 inch (25 mm) center to center. The gage of ties and spirals shall be as follows:

1. For piles having a least horizontal dimension of 16 inches (406 mm) or less, wire shall not be smaller than 0.22 inch (5.6 mm) (No. 5 gage).

2. For piles having a least horizontal dimension of more than 16 inches (406 mm) and less than 20 inches (508 mm), wire shall not be smaller than 0.238 inch (6 mm) (No. 4 gage).

3. For piles having a least horizontal dimension of 20 inches (508 mm) and larger, wire shall not be smaller than 1/4 inch (6.4 mm) round or 0.259 inch (6.6 mm) (No. 3 gage).
Piles shall be handled and driven so as not to cause injury or overstressing in a manner that affects durability or strength. A precast concrete pile shall not be driven before the concrete has attained a compressive strength of at least 75 percent of the 28-day specified compressive strength (f'c), and not less than the strength sufficient to withstand handling and driving forces.
Precast nonprestressed concrete piles shall conform to Sections 1809.6.2.1 through 1809.6.2.4.
Concrete shall have a 28-day specified compressive strength (f'c) of not less than 3,000 psi (20.68 MPa).
The minimum amount of longitudinal reinforcement shall be 0.8 percent of the concrete section and consist of at least four bars.
Where a structure is assigned to Seismic Design Category C in accordance with Section 1613, longitudinal reinforcement with a minimum steel ratio of 0.01 shall be provided throughout the length of precast concrete piles. Within three pile diameters of the bottom of the pile cap, the longitudinal reinforcement shall be confined with closed ties or spirals of a minimum 3/8-inch (9.5 mm) diameter. Ties or spirals shall be provided at a maximum spacing of eight times the diameter of the smallest longitudinal bar, not to exceed 6 inches (152 mm). Throughout the remainder of the pile, the closed ties or spirals shall have a maximum spacing of 16 times the smallest longitudinal-bar diameter, not to exceed 6 inches (152 mm).
Where a structure is assigned to Seismic Design Category D in accordance with Section 1613, the requirements of Seismic Design Category C shall apply, except that transverse reinforcement shall comply with requirements of Section 1810.1.2.5.
For allowable stresses, see Table 1808.8.
For concrete cover requirements, see Table 1808.2.13.
Precast prestressed concrete piles shall conform to the requirements of Sections 1809.6.3.1 through 1809.6.3.4.
Prestressing steel shall conform to ASTM A 416. Concrete shall have a 28-day specified compressive strength (f'c) of not less than 5,000 psi (34.48 MPa).
Precast prestressed piles shall be designed to resist stresses induced by handling and driving as well as by loads. The effective prestress in the pile shall not be less than 400 psi (2.76 MPa) for piles less than 30 feet (9144 mm) in length, 550 psi (3.79 MPa) for piles between 30 and 50 feet (9144 mm and 15 240 mm) in length and 700 psi (4.83 MPa) for piles greater than 50 feet (15 240 mm) in length. Effective prestress shall be based on an assumed loss of 30,000 psi (207 MPa) in the prestressing steel. The tensile stress in the prestressing steel shall not exceed the values specified in ACI 318.
Where a structure is assigned to Seismic Design Category C in accordance with Section 1613, precast prestressed piles shall have transverse reinforcement in accordance with this section. The minimum volumetric ratio of spiral reinforcement shall not be less than the amount required by the following formula for the upper 20 feet (6096 mm) of the pile.



where:

f 'c = Specified compressive strength of concrete, psi (MPa).
fyh = Yield strength of spiral reinforcement £ 85,000 psi (586 MPa).
ρs = Spiral reinforcement index (vol. spiral/vol. core).


At least one-half the volumetric ratio required by Equation 18-4 shall be provided below the upper 20 feet (6096 mm) of the pile.

The pile cap connection by means of dowels as indicated in Section 1808.9 is permitted. Pile cap connection by means of developing pile reinforcing strand is permitted provided that the pile reinforcing strand results in a ductile connection.
Where a structure is assigned to Seismic Design Category D in accordance with Section 1613.5.6, the requirements for Seismic Design Category C in Section 1809.6.3.2.1 shall be met, in addition to the following:

1. Requirements in ACI 318, Chapter 21, do not apply, unless specifically referenced.

2. Where the total pile length in the soil is 35 feet (10 668 mm) or less, the lateral transverse reinforcement in the ductile region shall occur through the length of the pile. Where the pile length exceeds 35 feet (10 668 mm), the ductile pile region shall be taken as the greater of 35 feet (10 668 mm) or the distance from the underside of the pile cap to the point of zero curvature plus three times the least pile dimension.

3. In the ductile region, the center-to-center spacing of the spirals or hoop reinforcement shall not exceed one-fifth of the least pile dimension, six times the diameter of the longitudinal strand, or 8 inches (203 mm), whichever is smaller.

4. Circular spiral reinforcement shall be spliced by lapping one full turn and bending the end of the spiral to a 90-degree hook or by use of a mechanical or welded splice complying with Section 12.14.3 of ACI 318.

5. Where the transverse reinforcement consists of circular spirals, the volumetric ratio of spiral transverse reinforcement in the ductile region shall comply with the following:

but not less than
and need not exceed:


where:

Ag = Pile cross-sectional area, square inches (mm2).
Ach = Core area defined by spiral outside diameter, square inches (mm2).
f 'c = Specified compressive strength of concrete, psi (MPa).
fyh = Yield strength of spiral reinforcement £ 85,000 psi (586 MPa).
P = Axial load on pile, pounds (kN), as determined from Equations 16-5 and 16-7.
ρs = Volumetric ratio (vol. spiral/vol. core).


6. When transverse reinforcement consists of rectangular hoops and cross ties, the total cross-sectional area of lateral transverse reinforcement in the ductile region with spacings, and perpendicular to dimension, hc, shall conform to:

but not less than:


where:

fyh = ≤ 70,000 psi (483 MPa).
hc = Cross-sectional dimension of pile core measured center to center of hoop reinforcement, inch (mm).
s = Spacing of transverse reinforcement measured along length of pile, inch (mm).
Ash = Cross-sectional area of tranverse reinforcement, square inches (mm2).
f 'c = Specified compressive strength of concrete, psi (MPa).


The hoops and cross ties shall be equivalent to deformed bars not less than No. 3 in size. Rectangular hoop ends shall terminate at a corner with seismic hooks.

Outside of the length of the pile requiring transverse confinement reinforcing, the spiral or hoop reinforcing with a volumetric ratio not less than one-half of that required for transverse confinement reinforcing shall be provided.
For allowable stresses, see Table 1808.8.
For concrete cover requirements, see Table 1808.2.13.
Structural steel piles shall conform to the requirements of Sections 1809.7.1 through 1809.7.4.
Structural steel piles, steel pipe and fully welded steel piles fabricated from plates shall conform to ASTM A 36, ASTM A 252, ASTM A 283, ASTM A 572, ASTM A 588, ASTM A 690, ASTM A 913 or ASTM A 992.
For the allowable stresses for materials used in piles see Table 1808.8.
Sections of H-piles shall comply with the following:

1. The flange projections shall not exceed 14 times the minimum thickness of metal in either the flange or the web and the flange widths shall not be less than 80 percent of the depth of the section.

2. The nominal depth in the direction of the web shall not be less than 8 inches (203 mm).

3. Flanges and web shall have a minimum nominal thickness of 3/8 inch (9.5 mm).
Steel pipe piles driven open ended shall have a nominal outside diameter of not less than 8 inches (203 mm). The pipe shall have a minimum of 0.34 square inch (219 mm2) of steel in cross section to resist each 1,000 foot-pounds (1356 N×m) of pile hammer energy or the equivalent strength for steels having a yield strength greater than 35,000 psi (241 MPa), or the wave equation analysis shall be permitted to be used to assess compression stresses induced by driving to evaluate if the pile section is appropriate for the selected hammer. Where pipe wall thickness less than 0.188 inch (4.8 mm) is driven open ended, a suitable cutting shoe shall be provided.
The materials, reinforcement and installation of cast-in-place concrete piles shall conform to Sections 1810.1.1 through 1810.1.3.
Concrete or grout shall have a 28-day specified compressive strength (f'c) of not less than 2,500 psi (17.24 MPa), except in micropiles and caisson piles where the minimum compressive strength shall be 4,000 psi (27 580 kPa). Where concrete is placed through a funnel hopper at the top of the pile, the concrete mix shall be designed and proportioned so as to produce a cohesive workable mix having a slump of not less than 4 inches (102 mm) and not more than 6 inches (152 mm). Where concrete or grout is to be pumped, the mix design shall be such that material produced is suitable for pumping.
Reinforcement where required shall be placed in accordance with Section 1810.3.4 and shall be assembled, tied together, and placed in the pile as a unit before concrete or grout is placed.

Exceptions: Where approved by the engineer, reinforcement may be placed after the piles are filled with concrete or grout under the following situations:

1. Tied reinforcement in augered uncased cast-in-place piles, while the concrete or grout is still in a semifluid state.

2. Tied reinforcement in piles filled with grout, while the grout is in a semifluid state.

3. Steel dowels embedded 5 feet (1524 mm) or less in the pile while the concrete or grout is still in a semifluid state.
The design cracking moment (φMn) for a cast-in-place deep foundation element not enclosed by a structural steel pipe or tube shall be determined using the following equation:




where:

f 'c = Specified compressive strength of concrete or grout, psi (MPa).
Sm = Elastic section modulus, neglecting reinforcement and casing, cubic inches (mm3).
Where subject to uplift, or where the required moment strength determined using the load combinations of Section 1605.2 exceeds the design cracking moment determined in accordance with Section 1810.1.2.1, cast-in-place concrete piles not enclosed by a structural steel pipe or tube shall be reinforced.
Where a structure is assigned to Seismic Design Category C in accordance with Section 1613, reinforcement shall be provided in accordance with Section 1810.1.2.4. Where a structure is assigned to Seismic Design Category D, reinforcement shall be provided in accordance with Section 1810.1.2.5.
For structures assigned to Seismic Design Category C in accordance with Section 1613, cast-in-place deep foundation elements shall be reinforced as specified in this section. Reinforcement shall be provided where required by analysis. A minimum of four longitudinal bars, with a minimum longitudinal reinforcement ratio of 0.0025, shall be provided throughout the minimum reinforced length of the element as defined below starting at the top of the element. The minimum reinforced length of the element shall be the greatest of the following:

1. One-third of the element length;

2. A distance of 10 feet (3048 mm);

3. Three times the least element dimension; or

4. The distance from the top of the element to the point where the design cracking moment determined in accordance with Section 1810.1.2.1 exceeds the required moment strength determined using the load combinations of Section 1605.2.

Transverse reinforcement shall consist of closed ties or spirals with a minimum diameter of 3/8 inch (9.5 mm). Spacing of transverse reinforcement shall not exceed the smaller of 6 inches (152 mm) or 8-longitudinal-bar diameters, within a distance of three times the least element dimension from the bottom of the pile cap. Spacing of transverse reinforcement shall not exceed 16 longitudinal bar diameters throughout the remainder of the reinforced length.

Exceptions:

1. The requirements of this section shall not apply to concrete cast in structural steel pipes or tubes.

2. A spiral-welded metal casing of a thickness not less than manufacturer’s standard No. 14 gage (0.068 inch) (1.73 mm) is permitted to provide concrete confinement in lieu of the closed ties or spirals. Where used as such, the metal casing shall be protected against possible deleterious action due to soil constituents, changing water levels or other factors indicated by boring records of site conditions.
For structures assigned to Seismic Design Category D in accordance with Section 1613, cast-in-place deep foundation elements shall be reinforced as specified in this section. Reinforcement shall be provided where required by analysis. A minimum of four longitudinal bars, with a minimum longitudinal reinforcement ratio of 0.005, shall be provided throughout the minimum reinforced length of the element as defined below starting at the top of the element.

The minimum reinforced length of the element shall be the greatest of the following:

1. One-half of the element length;

2. A distance of 10 feet (3048 mm);

3. Three times the least element dimension; or

4. The distance from the top of the element to the point where the design cracking moment determined in accordance with Section 1810.3.9.1 exceeds the required moment strength determined using the load combinations of Section 1605.2.

Transverse reinforcement shall consist of closed ties or spirals no smaller than No. 3 bars for elements with a least dimension of up to 20 inches (508 mm), and No. 4 bars for larger elements. Throughout the remainder of the reinforced length outside the regions with transverse confinement reinforcement, as specified in Section 1810.1.2.5.1 or 1810.1.2.5.2, the spacing of transverse reinforcement shall not exceed the least of the following:

1. 12 longitudinal bar diameters;

2. One-half the least dimension of the element; or

3. 12 inches (305 mm).

Exceptions:

1. The requirements of this section shall not apply to concrete cast in structural steel pipes or tubes.

2. A spiral-welded metal casing of a thickness not less than manufacturer’s standard gage No. 14 gage (0.068 inch) (1.73 mm) is permitted to provide concrete confinement in lieu of the closed ties or spirals. Where used as such, the metal casing shall be protected against possible deleterious action due to soil constituents, changing water levels or other factors indicated by boring records of site conditions.
For Site Class A, B, C and D, transverse confinement reinforcement shall be provided in the element in accordance with Sections 21.6.4.2, through 21.6.4.4 of ACI 318 within three times the least element dimension of the bottom of the pile cap. A transverse spiral reinforcement ratio of not less than one-half of that required in Section 21.6.4.4(a) of ACI 318 shall be permitted.
For Site Class E or F, transverse confinement reinforcement shall be provided in the element in accordance with Sections 21.6.4.2 through 21.6.4.4 of ACI 318 within seven times the least element dimension of the pile cap and within seven times the least element dimension of the interfaces of strata of Class 4b or better and strata that are liquefiable or are composed of material meeting Class 4c or 6.
Concrete or grout shall be placed in such a manner as to ensure the exclusion of any foreign matter and to secure a full-sized shaft. Concrete or grout shall not be placed through water except where a tremie or other approved method is used. When depositing concrete from the top of the pile, the concrete shall not be chuted directly into the pile but shall be poured in a rapid and continuous operation through a funnel hopper centered at the top of the pile. Grout for auger cast piles shall be pumped through a hollow stem auger and shall be maintained as fluid throughout placement.
Enlarged base piles shall conform to the requirements of Sections 1810.2.1 through 1810.2.5.
The maximum size of coarse aggregate for concrete shall be 3/4 inch (19.1 mm). Concrete to be compacted shall have a zero slump.
For allowable stresses, see Table 1808.8.
Enlarged bases formed either by compacting concrete or driving a precast base shall be formed in or driven into granular soils. Piles shall be constructed in the same manner as successful prototype test piles driven for the project. Pile shafts extending through peat or other organic soil shall be encased in a permanent steel casing. Where a cased shaft is used, the shaft shall be adequately reinforced to resist column action or the annular space around the pile shaft shall be filled sufficiently to re-establish lateral support by the soil. Where pile heave occurs, the pile shall be replaced unless it is demonstrated that the pile is undamaged and capable of carrying twice its design load.
Pile load-bearing capacity shall be verified by load tests in accordance with Section 1808.4.
For minimum concrete cover requirements see Table 1802.13.
Drilled or augered uncased piles shall conform to Sections 1810.3.1 through 1810.3.5.
For allowable stresses, see Table 1808.8.
The minimum diameter of drilled or augered uncased piles shall be 12 inches (305 mm).
Where pile shafts are formed through unstable soils and concrete is placed in an open-drilled hole, a steel liner shall be inserted in the hole prior to placing the concrete. Where the steel liner is withdrawn during concreting, the level of concrete shall be maintained above the bottom of the liner at a sufficient height to offset any hydrostatic or lateral soil pressure.

Where grout is placed by pumping through a hollow-stem auger, the auger shall be permitted to rotate in a clockwise direction during withdrawal. An initial head of grout shall be established and maintained on the auger flights before withdrawal. The auger shall be withdrawn in a continuous manner in increments of about 12 inches (305 mm) each. Grout pumping pressures shall be measured and maintained high enough at all times to offset hydrostatic and lateral earth pressures. Grout volumes shall be measured to ensure that the volume of grout placed in each pile is equal to or greater than the theoretical volume of the hole created by the auger. Where the installation process of any pile is interrupted or a loss of grout pressure occurs, the pile shall be re-drilled to 5 feet (1524 mm) below the elevation of the tip of the auger when the installation was interrupted or grout pressure was lost and reformed. Augered cast-in-place piles shall not be installed within six pile diameters center to center of a pile filled with concrete or grout less than 12 hours old, unless approved by the engineer. The level at which return of the grout occurs during withdrawal shall be recorded. If the grout level in any completed pile drops during installation of an adjacent pile, the pile shall be replaced. The installation shall be performed under the direct supervision of the engineer. The engineer shall certify to the commissioner that the piles were installed in compliance with the approved construction documents.
For piles installed with a hollow-stem auger, where full-length longitudinal steel reinforcement is placed without lateral ties, the reinforcement shall be placed through ducts in the auger prior to filling the pile with concrete. Concrete cover for pile reinforcement shall be in accordance with Table 1808.2.13.

Exception: Where physical constraints do not allow the placement of the longitudinal reinforcement prior to filling the pile with concrete or where partial-length longitudinal reinforcement is placed without lateral ties, the reinforcement is allowed to be placed after the piles are completely concreted but while concrete is still in a semifluid state.
Where a structure is assigned to Seismic Design Category C or D in accordance with Section 1613, the corresponding requirements of Sections 1810.1.2.3 through 1810.1.2.5 shall be met.
Driven uncased piles shall not be permitted.
Steel-cased piles shall comply with the requirements of Sections 1810.5.1 through 1810.5.4.
Pile shells or casings shall be of steel and be sufficiently strong to resist collapse and sufficiently water tight to exclude any foreign materials during the placing of concrete. Steel shells shall have a sealed tip with a diameter of not less than 8 inches (203 mm).
For allowable stresses, see Table 1808.8.
The thickness of the steel shell shall not be less than manufacturer’s standard No. 14 gage (0.068 inch) (1.75 mm) minimum.
The shell shall be seamless or provided with seams of strength equal to the basic material and be of a configuration that will provide confinement to the cast-in-place concrete.
The ratio of steel yield strength (fy) to 28-day specified compressive strength (f'c)‡ shall not be less than six.
The nominal pile diameter shall not be greater than 16 inches (406 mm).
Steel shells shall be mandrel driven for their full length in contact with the surrounding soil. The steel shells shall be driven in such order and with such pacing as to ensure against distortion of or injury to piles already in place. A pile shall not be driven within four and one-half average pile diameters of a pile filled with concrete less than 24 hours old unless approved by the commissioner. Concrete shall not be placed in steel shells within heave range of driving.
Reinforcing shall be required for unsupported pile lengths or where the pile is designed to resist uplift or unbalanced lateral loads. For minimum concrete cover requirements, see Table 1808.2.13.
Where a structure is assigned to Seismic Design Category C or D in accordance with Section 1613, the reinforcement requirements of Sections 1810.1.2.3 through 1810.2.5 shall be met.
Concrete-filled steel pipe and tube piles shall conform to the requirements of Sections 1810.6.1 through 1810.6.5.
Steel pipe and tube sections used for piles shall conform to ASTM A 252 or ASTM A 283. Concrete shall conform to Section 1810.1.1. The maximum coarse aggregate size shall be 3/4 inch (19.1 mm).
For allowable stresses, see Table 1808.8.
Piles shall have a nominal outside diameter of not less than 8 inches (203 mm) and a minimum wall thickness in accordance with Section 1809.3.4. For mandrel-driven pipe piles, the minimum wall thickness shall be 1/10 inch (2.5 mm).
Reinforcement steel shall conform to Section 1810.1.2. For minimum concrete cover requirements see Table 1808.2.13.
Where a structure is assigned to Seismic Design Category C or D in accordance with Section 1613, minimum reinforcement no less than 0.01 times the cross-sectional area of the pile concrete shall be provided in the top of the pile with an embedment length equal to two times the required cap embedment anchorage into the pile cap, but not less than the tension development length of the reinforcement. The wall thickness of the steel pipe shall not be less than 3/16 inch (5 mm).
The placement of concrete shall conform to Section 1810.1.3.
Caisson piles shall conform to the requirements of Sections 1810.7.1 through 1810.7.7.
Caisson piles shall consist of a shaft section of concrete or grout-filled pipe, extending to bedrock, with an uncased socket drilled into bedrock of Class 1c or better and filled with concrete or grout. The caisson pile shall have a full-length structural steel core, full length steel reinforcing, or a stub core or steel reinforcing installed in the rock socket and extending into the pipe portion a distance equal to the socket depth. The minimum outside diameter of the caisson pile shall be 7 inches (194 mm), and the diameter of the rock socket shall be approximately equal to the inside diameter of the pile.
Pipe and steel cores shall conform to the material requirements in Section 1809.3. Pipes shall have a minimum wall thickness of 3/8 inch (9.5 mm) and shall be fitted with a suitable steel-driving shoe or cutting teeth welded to the bottom of the pipe. Concrete or grout shall have a 28-day specified compressive strength (f'c) of not less than 4,000 psi (27.58 MPa).
For the purposes of Section 1810.7, threaded bars conforming to ASTM A 615 and ASTM A 722 shall be considered the same as deformed reinforcing bars.
The depth of the rock socket in Class 1c rock or better shall be sufficient to develop the full load-bearing capacity of the caisson pile based upon the sum of the allowable bearing pressure on the bottom of the socket in accordance with Table 1804.1 plus an allowable bond stress of 200 psi on the sides of the socket. The depth of the socket in Class 1c rock or better below the bottom of the pipe shall not be less than 3 feet (914 mm) of the outside diameter of the pipe.
Load tests, with instrumentation in the rock socket to demonstrate the transfer of force to the rock, shall be performed to justify the use of bond stresses above 200 psi (1379 kPa). The number of load tests shall be in accordance with the requirements of Section 1808.4.1.1. A report summarizing the methods and results of the load test shall be submitted to the commissioner for approval.
The gross cross-sectional area of the structural steel core or bundled center reinforcing shall not exceed 30 percent of the gross area of the caisson. For reinforcing placed at the perimeter of the caisson, the area of the reinforcing shall not exceed 8 percent of the area inside the casing. Minimum concrete cover shall be in accordance with Table 1808.2.13.
Steel reinforcing shall be spliced in accordance with the requirements of ACI 318.
Where a structure is assigned to Seismic Design Category C or D in accordance with Section 1613, the reinforcement requirements of Section 1810.6.4.1 shall be met.
For allowable stresses, see Table 1808.8.
The rock socket and pile shall be thoroughly cleaned of foreign materials before filling with concrete or grout. Steel cores shall be set within 6 inches (125 mm) above the base of the rock socket. Concrete shall not be placed through water except where a tremie or other method approved by the commissioner is used.
Caisson rock sockets shall be subject to special inspection in accordance with Section 1704.9. All caisson rock sockets shall be inspected to verify rock quality. Inspection may be accomplished by direct observation, by video methods or by a core boring performed prior to the drilling of the socket.
Micropiles shall conform to Sections 1810.8.1 through 1810.8.6.
Reinforcement shall consist of deformed reinforcing bars in accordance with ASTM A 615 Grade 60 or 75 or ASTM A 722 Grade 150. The steel pipe or casing shall have a minimum yield strength of 45,000 psi (310 MPa) and a minimum elongation of 15 percent as shown by mill certifications or two coupon test samples per 40,000 pounds (18 160 kg) of pipe or casing.
Micropiles shall have an outside diameter of between 5 and 14 inches (127 and 356 mm). The minimum diameter set forth elsewhere in Section 1810.3.5 shall not apply to micropiles. The steel pipe shall have a minimum wall thickness of 3/16 inch (4.8 mm).
Micropiles shall develop their load-carrying capacity by means of a bond zone in soil. The design of micropiles shall not consider end bearing. Micropiles shall be grouted and have either a steel pipe or steel reinforcement at every section along the length. It shall be permitted to transition compression loads from the steel pipe to the deformed reinforcing bars by extending the bars into the pipe section by at least their development length in tension, in accordance with ACI 318.
For micropiles or portions thereof grouted inside a temporary or permanent casing or a hole drilled with grout, the steel pipe or steel reinforcement shall be designed to carry at least 40 percent of the design compression load. Micropiles or portions thereof grouted in an open hole in soil without temporary or permanent casing and without suitable means of verifying the hole diameter during grouting shall be designed to carry the entire compression load in the reinforcing steel. Where a steel pipe is used for reinforcement, the portion of the grout enclosed within the pipe is permitted to be included in the determination of the allowable stress in the grout.
For structures assigned to Seismic Design Category C, a permanent steel casing shall be provided from the top of the micropile down to the point of zero curvature. For structures assigned to Seismic Design Category D, the micropile shall be approved by the commissioner in accordance with Section 28-113.2 of the New York City Administrative Code. The alternative system design, supporting documentation and test data shall be submitted to the commissioner for review and approval.
Splices in reinforcing bars shall be made in accordance with ACI 318. Splices in the steel pipe or casing shall be made by use of flush threaded joints, or by welded joints. Reductions for the structural capacity of the threaded joint casing at splice locations shall be accounted for in the design.
Micropile deep foundation elements shall be permitted to be formed in holes advanced by rotary or percussive drilling methods, with or without casing. The elements shall be grouted with a fluid cement grout. The grout shall be pumped through a tremie pipe extending to the bottom of the element until grout of suitable quality returns at the top of the element. The following requirements apply to specific installation methods:

1. For micropiles grouted inside a temporary casing, the reinforcing bars shall be inserted prior to withdrawal of the casing. The casing shall be withdrawn in a controlled manner with the grout level maintained at the top of the element to ensure that the grout completely fills the drill hole.

2. For a micropile or portion thereof grouted in an open drill hole in soil without a temporary casing, the minimum design diameter of the drill hole shall be verified by a suitable device prior to grouting.

3. Subsequent micropiles shall not be drilled near elements that have been grouted until the grout has had sufficient time to harden.

4. Micropiles shall be grouted as soon as possible after drilling is completed.

5. For micropiles designed with a full-length casing, the casing shall be pulled back to the top of the bond zone and reinserted or some other suitable means employed to assure grout coverage outside the casing.
Where existing structures may be affected by subsurface disturbances, air drilling shall be prohibited.
Micropiles shall be installed with a pressure grouted bond zone. The bond zone shall be formed entirely in soil of Class 4 or better and the grout shall be placed under pressure exceeding 1.5 times the existing total overburden pressure. The bond zone shall be formed by extending the casing to the bottom of the bond zone and withdrawing the casing while the grout is being pumped under pressure. The casing above the bond zone shall remain in place permanently. Reinforcing to the bond zone shall be placed in the casing to the depth of the bond zone prior to placing grout.
Composite piles shall conform to the requirements of Sections 1811.2 through 1811.5.
Composite piles consisting of two or more approved pile types shall be designed to meet the conditions of installation.
The maximum allowable load shall be limited by the capacity of the weakest section incorporated in the pile.
Splices between concrete and steel or wood sections shall be designed to prevent separation both before and after the concrete portion has set, and to ensure the alignment and transmission of the total pile load. Splices shall be designed to resist uplift caused by upheaval during driving of adjacent piles, and shall develop the full compressive strength and not less than 50 percent of the tension and bending strength of the weaker section.
Where a structure is assigned to Seismic Design Category C or D, in accordance with Section 1613 and where concrete and steel are used as part of the pile assembly, the concrete reinforcement shall comply with Sections 1810.1.2.3 and 1810.1.2.5 and the steel section shall comply with Section 1809.7.4 or 1810.6.4.1.
Helical piles may be used to support axial compression, or resist axial tension and lateral loads. All helical pile foundation systems shall be approved by the commissioner in accordance with Section 28-113.2 of the Administrative Code.
Design of helical pile foundations shall be based on a geotechnical investigation in accordance with Sections 1802 and 1808.2 with the following additional conditions stated in Sections 1812.2.1 and 1812.2.2.

Exception: For the repair of residential porches, stoops and slab on grades, helical test probes may be used to substitute for test borings, provided the pile has a torque to capacity ratio approved in accordance with Section 28-113.2.1 of the Administrative Code.
Tests shall be performed in each soil layer for soil resistivity, soil pH, organic content and sulphate concentration. The device or system shall not be used in conditions that are indicative of a potential pile corrosion situation, as defined by soil resistivity less than 1,000 ohm-cm, pH less than 5.5, soils with high organic content, sulfate concentrations greater than 1,000 ppm, landfills, or mine waste.
In addition to the protective treatment requirements of Section 1808.2.12, helical pile design shall consider the abrasive action inherent in the installation process when protective exterior treatment is specified as pile protection.
The allowable load of helical piles shall be in accordance with the applicable provisions of Section 1808.3. In addition, the requirements of this section shall apply.
The allowable axial tension and compression load shall not exceed 30 tons (267 kN).
The allowable lateral load resisted by a helical pile shall not exceed 3 tons (29.4 kN).
Load tests shall be in accordance with Sections 1808.4 and 1812.4.1 through 1812.4.4.
The allowable axial compression load of a helical pile shall be verified by load tests in accordance with the requirements of Section 1808.4, except that ASTM D 1143 may be conducted using the Quick Load Test Loading Procedure. Following each compression load test, the test pile shall be removed by unscrewing and inspected for any deformations to the helices, to verify the structural integrity of the shaft and its connections.
The number of axial compression load tests shall satisfy Section 1808.4.

Exception: Pile load tests shall not be required, provided the following conditions are satisfied:

1. The pile has a torque to capacity ratio approved in accordance with Section 28-113.2.1 of the Administrative Code;

2. The torque correlation shall demonstrate a factor of safety (FS) of 2.5 on the allowable load; and

3. The maximum allowable axial compression load on the helical pile shall be 10 tons (98 kN).
The allowable pile load shall be computed in accordance with Section 1808.4.1.5.
The allowable axial tension load of a helical pile shall be verified by load testing in accordance with Section 1808.4; however, it shall be permitted to use the Quick Load Test Loading Procedure of ASTM D 3689. Following the tension load test, the pile shall be removed by unscrewing, and shall be inspected for any deformations to the helices and to verify the structural integrity of the shaft and connections.
The number of axial tension load tests shall satisfy Section 1808.4, but with a minimum of one test.
The allowable lateral load of a helical pile shall be verified with load testing in accordance with Section 1808.4. Following the lateral load test, the pile shall be removed by unscrewing and inspected for any deformations to the helices, to verify the structural integrity of the shaft and connections.
The number of lateral load tests shall satisfy Section 1808.4, but shall not be fewer than one test.
The allowable lateral pile load shall be computed in accordance with Sections 1808.4.3.1 and 1808.4.3.2.
Additional axial compression, axial tension and lateral load tests shall be performed for questionable construction as required by Section 1808.4.1.1.1.
Where load tests are required, the test pile shall be used to determine the minimum required site-specific torque for installation of production piles. For each helical pile, the special inspector shall measure and log the installation torque for each foot of depth and the final torque in the helice’s soil-bearing zone. The shaft advancement shall equal or exceed 85 percent of helix pitch per revolution at time of final torque measurement. Where load tests are not required, installation torque shall be in accordance with the exception defined under Section 1812.4.3.
Where bracket assemblies or structural eccentric forces cause bending, the resulting moment pile design shall ensure stability in accordance with Section 1808.2.5 and general engineering practice. Where side-mount brackets are used and a stability analysis indicates that there is insufficient internal stability to resist overturning and translation, helical piles shall be installed staggered or other means shall be designed to provide stability and prevent rotation of the foundation.
When helical piles are embedded in soils of Classes 6 and 7, a buckling analysis shall be performed by a recognized method. The allowable axial compressive load shall be not more than two-thirds of the calculated load-causing buckling. The additional bending moments due to bracket assemblies, structural eccentric forces and coupling rigidity shall be appropriately included in the buckling analysis.
Where a moment is transmitted to a single helical pile, a structural analysis shall be conducted to verify that the shaft is capable of resisting the moment with acceptable deflection.
Where side-mount brackets are used, each bracket assembly shall be proof-tested to a minimum 110 percent of allowable load to demonstrate that the bracket assembly is capable of transferring the loads to the pile. The load shall be applied in six equal increments. The 110 percent test load shall be held for a minimum 30 minutes without bracket assembly distortion or deformation. Side-mount brackets for permanent applications shall be encased in concrete with a minimum embedment of 3 inches (76.2 mm). Concrete used to encase side-mount brackets shall meet the requirements of Sections 1903, 1904, 1905 and 1906.
Minimum spacing between the center lines of helical piles shall be four times the largest helix plate diameter.
Equipment used for the installation of helical piles shall be as recommended by the helical pile manufacturer.
The installation of helical piles shall be subject to the special inspection requirements in Section 1704.8 and the following requirements:

1. The special inspector shall prepare a report of special inspections of helical piles, and submit such report to the department in a manner acceptable to the commissioner. In addition to the requirements of Section 1704.8, this report shall also include, at a minimum, the following:

1.1. Helical pile type and product specification sheet for the each helical pile installed as published by the manufacturer.

1.2. Make and model of the equipment used for installation.

1.3. Make and model number of the torque indicator used to measure installation torque.

1.4. Calibration records for the torque indicators used to install the helical piles.

1.5. The installation speed (rpm) of the helical pile.

1.6. From axial load tests and the site specific torque to capacity relationship, the minimum torque required to achieve the allowable pile load in tension or compression.

1.7. For each helical pile, the installation torque for each foot of depth and the final torque in the helice’s soil-bearing zone. The shaft advancement shall equal or exceed 85 percent of helix pitch per revolution at time of final torque measurement.

2. Field welds performed in the installation of a helical pile foundation system shall additionally be subject to the special inspection requirements of Section 1704.3.
An assessment of the liquefaction potential shall be determined for each building site except Structural Occupancy/Risk Category I structures. The evaluation of liquefaction potential shall include the following considerations:

1. Noncohesive granular soils below groundwater table and less than 50 feet (15 240 mm) below the ground surface shall be considered to have potential for liquefaction.

2. The potential for liquefaction on level ground shall be determined on the basis of the risk categories associated with the standard penetration resistance normalized to an energy of 60 percent efficiency (N60) at the site, as defined in Figure 1813.1, or a site-specific analysis performed by a geotechnical engineer.

3. Clays, silts and clayey silts below the groundwater table and less than 50 feet (15 240 mm) below the ground surface with a plasticity index less than 20 shall be considered to have potential for liquefaction. The susceptibility of the fine grained soils shall be evaluated in accordance with generally accepted engineering practice or a site-specific analysis performed by a geotechnical engineer.


FIGURE 1813.1 LIQUEFACTION ASSESSMENT DIAGRAM
In evaluating liquefaction potential, the analysis shall consider the following parameters: peak ground acceleration, earthquake magnitude, magnitude scaling factor, effective overburden pressure, hammer energy, cone penetration resistance (where applicable), and fines content. If a site response analysis is conducted, bedrock acceleration time histories and a shear wave velocity profile based on in-situ measurements may be utilized. These analyses may consider the results of laboratory cyclic shear tests. Where borings are drilled for the purpose of site-specific analyses and for the purpose of evaluating liquefaction potential, the drilling and sampling procedures and apparatus shall be in accordance with ASTM D 6066.
Peak ground acceleration shall be determined based on either (1) a site-specific study taking into account soil amplification effects as specified in Section 11.4.7 of ASCE 7-10 or (2) the Maximum Considered Geometric Mean peak ground acceleration adjusted for Site Class effects PGAM as provided in Table 1813.2.1 without adjustment for targeted risk.

Limit Lines
Structural Risk/Occupancy Category II/III
Structural Risk/ Occupancy Category IV


Notes:

1) Diagram is applicable only to soils below the groundwater table.

2) N60 is the standard penetration resistance normalized to an energy of 60 percent efficiency.

3) See Table 1604.5 for Structural Risk/Occupancy Category definitions.

4) Structural Risk/Occupancy Category I structures are exempt from liquefaction assessment.

TABLE 1813.2.1 VALUES OF MAXIMUM CONSIDERED EARTHQUAKE GEOMETRIC MEAN (MCEG) PEAK GROUND ACCELERATIONS ADJUSTED FOR SITE CLASS EFFECTS, PGAM

SITE CLASS PGAM(g)
A 0.14
B 0.17
C 0.20
D 0.24
E 0.33
The foundation design analysis shall consider an assessment of the potential consequences of any liquefaction and soil strength loss, including an estimation of total and differential settlement, lateral movement or reduction in foundation soil-bearing capacity, and may incorporate the potential benefits of any proposed mitigation measures. Such measures may be given consideration in the design of the structure and may include, but are not limited to, ground improvement, pore pressure dissipation, selection of appropriate foundation type and depths, selection of appropriate structural systems to accommodate anticipated displacements, or any combination of these measures.

In evaluating the potential for liquefaction, the effect of settlements induced by seismic motions and loss of soil strength shall be considered. The analysis performed shall incorporate the effects of the maximum considered earthquake (MCE) peak ground acceleration, appropriate earthquake magnitudes and duration consistent with the design earthquake ground motions as well as uncertainty and variability of soil properties across the site. The MCE peak ground acceleration, seismically induced cyclic stress ratios and pore pressure development may be determined from a site-specific study taking into account soil amplification effects and design ground motions appropriate for the seismic hazard. Other recognized methods of analysis may be used in the evaluation process subject to the approval of the commissioner. Effects of liquefaction shall be considered in the design except when the following conditions exist:

1. Structures classified as Risk Category I.

2. When the calculated cyclic resistance ratio (CRR) is greater than or equal to the calculated cyclic stress ratio (CSR) for Risk Category II and III structures.

3. When the calculated CRR is greater than 1.2 times the calculated CSR for Risk Category IV structures.
Where liquefaction is determined to be probable, the following considerations shall be addressed in the design:

1. Liquefiable soils shall be considered to have no passive (lateral) resistance or bearing capacity value for the design earthquake, unless shown otherwise by accepted methods of analysis. The engineer shall submit an analysis for review and approval by the commissioner, demonstrating that the proposed construction is safe against the effects of soil liquefaction.

2. Where liquefiable soils are present in sloped ground or over sloped nonliquefiable substrata and where lateral displacement is possible, the engineer shall submit a stability analysis for review and approval by the commissioner, demonstrating that the proposed construction is safe against failure of the soil and that the effects of potential lateral displacements are acceptable.
Where the protection and/or support of a structure or property adjacent to an excavation is required, an engineer shall prepare a preconstruction report summarizing the condition of the structure or property. The preconstruction report shall be prepared based on an examination of the structure or property, the review of available documents and, if necessary, the excavation of test pits. The engineer shall determine the requirements for underpinning or other protection and prepare site and structure-specific plans, including details and sequence of work for submission to the commissioner. Such protection may be provided by underpinning, sheeting, and bracing, or by other means acceptable to the commissioner.
Underpinning piers, walls, piles and footings shall be designed as permanent structural elements and installed in accordance with provisions of this chapter and Chapter 33 and shall be inspected in accordance with the provisions of Chapter 17. Underpinning shall be designed and installed in such manner so as to limit the lateral and vertical displacement of the adjacent structure to permissible values as established in accordance with Section 1814.3. The sequence of installation and the requirements for sheeting, preloading, wedging with steel wedges, jacking or dry packing shall be identified in the design. The design shall take in account the effects on foundation and structure produced by the lateral earth pressure exerted on the underpinning. Lateral support for underpinning, if needed, shall be accounted for during the design of the new construction. The design and construction sequence of temporary lateral supports used prior to the installation of the foundation walls shall be included on the design drawings.
Existing structures founded at a level above the level of adjacent new construction may be supported on Class 1a and 1b rock in lieu of underpinning, sheeting and bracing or retaining walls, provided that a report by the engineer substantiates the safety of the proposed construction. The engineer shall also certify that the he or she has inspected the exposed rock and the jointing therein and has determined whether supplemental support of the rock face is required.
When excavation, foundation construction, or underpinning is required, adjacent structures and properties shall be monitored in accordance with a plan prepared by the engineer. The engineer shall develop the scope of the monitoring program, including location and type of instruments, frequency and duration of readings, and permissible movement and vibration criteria. This scope shall take into account the structures or property to be monitored and the conditions thereof. The monitoring program shall include necessary actions to address exceedances. These actions shall include notification of the commissioner. Monitoring of historic and landmarked structures shall be subject to special requirements as determined by the department.
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