Article 2 Procedures for Structural Evaluation of Buildings
- 1.1 Site visit and data collection;
- 1.2 Identification of building type;
- 1.3 Completion of evaluation statements in appendix;
- 1.4 Follow-up field work, if required;
- 1.5 Follow-up analysis for "False" evaluation statements;
- 1.6 Final evaluation for the building;
- 1.7 Preparation of the evaluation report; and
- 1.8 Submittal of evaluation report to OSHPD.
- The building was designed and constructed to the 1989 or later edition of Part 2, Title 24, and
- If any portion of the structure, except for the penthouse, is of steel moment resisting frame construction (Building Type 3, or Building Type 4 or 6 with dual lateral system, as defined in Section 2.2.3) and the building permit was issued after October 25, 1994.
- 2.2 All other conforming buildings as defined in Article 1, Section 1.2, may be placed into SPC 4 in accordance with Table 2.5.3, except those required by Section 4.2.10 to be placed in SPC 3 in accordance with Table 2.5.3, without the need for any structural evaluation.
- 2.3 Nonconforming buildings as defined in Article 1, Section 1.2 may be placed into SPC 1 in accordance with Table 2.5.3 without any structural evaluation.
SOIL PROFILE TYPES AND SITE COEFFICIENTS
|PROFILE WITH||SITE |
|S1||Rock of any characteristic, either shalelike or crystalline in nature. Such material may be characterized by a shear wave velocity greater than 2,500 feet per second or by other appropriate means of classification.||1.0|
|Stiff soil conditions where the soil depth is less than 200 feet and the soil types overlying rock are stable deposits of sands, gravels or stiff clays.|
|S2||Deep cohesionless or stiff clay conditions, including sites where the soil depth exceeds 200 feet and the soil types overlying rock are stable deposits of sands, gravels or stiff clays.||1.2|
|S3||Soft- to medium-stiff clays and sands characterized by 30 feet or more of soft- to medium-stiff clays with or without intervening layers of sand or other cohesionless soils.||1.5|
|S4||More than 70 feet of soft clays or silts characterized by a shear wave velocity less than 400 feet per second.||2.0|
EFFECTIVE PEAK ACCELERATION COEFFICIENT (Aa) AND EFFECTIVE PEAK VELOCITY COEFFICIENT (Av) FOR CALIFORNIA
|No.||County||EPA Aa||EPV Av|
|40||San Luis Obispo||0.40||0.40|
- The evaluator shall visit the building to observe and record the type, nature and physical condition of the structure.
- Reports are not required for one-story, wood-frame and light steel-frame buildings of Type II or Type V construction and 4,000 square feet or less in floor area;
- A previous report for a specific site may be resubmitted, provided that a reevaluation is made and the report is found by the Office to be currently appropriate.
- The value of the effective peak acceleration coefficient (Aa) from Figure 2.1 and 2.1a;
- The value of the effective peak velocity-related acceleration coefficient (Av) from Figure 2.1 and 2.1a;
- The soil profile type (S1, S2, S3 or S4) derived from the geotechnical report or from Table 2.1;
- The site coefficient, (S), from Table 2.1; and
- The ground motion parameters and near field effects in strong ground shaking required for the evaluation of welded steel moment frame structures in accordance with Sections 188.8.131.52, 184.108.40.206 and 4.2.10.
- Construction drawings, specifications and calculations for the original building (Note: when reviewing and making use of existing analyses and structural member checks, the evaluator shall assess and report the basis of the earlier work);
- All drawings, specifications and calculations for remodeling work; and
- Material tests and inspection reports for nonconforming buildings. If the original drawings are available, but material test and inspection reports are not available, perform the testing program as specified in Section 220.127.116.11.
- Verify existing data;
- Develop other needed data (e.g., measure and sketch building as outlined in Section 2.1.2);
- Verify the vertical and lateral systems;
- Check the condition of the building; and
- Identify special conditions, anomalies and oddities.
- Review other data available such as assessments of building performance following past earthquakes.
- Prepare a summary of the data using an OSHPD- approved format.
- Perform the evaluation using the procedures in Sections 2.2 through 2.5.
- Prepare a report of the findings of the evaluation using an OSHPD-approved format.
Building information pertinent to a structure's seismic performance, including condition, configuration, detailing, material strengths and foundation type, shall be obtained in accordance with this section, and documented on drawings and/or sketches that shall be included with the structural calculations.
Exception: Materials testing is not required for reclassification by the collapse probability assessment option as permitted by Section 18.104.22.168.2, where nonavailability of materials test is identified as a deficiency in accordance with Section 22.214.171.124(b).
Characteristics of the building relevant to its seismic performance shall be obtained for use in the building evaluation. This shall include current information on the building's condition, configuration, material strengths, detailing and foundation type. This data shall be obtained from:
- Review of construction documents;
- Destructive and nondestructive testing and examination of selected building components; and
- Field observation of exposed conditions to verify that field conditions substantially match the construction documents in accordance with data collection requirements in the California Existing Building Code Section 303A.3.5.3, or equivalent provisions in later editions of the CEBC.
The characteristics of the building shall be established, including identification of the gravity- and lateral-load-carrying systems. The effective lateral-load carrying system may include structural and nonstructural elements that will participate in providing lateral resistance, although these elements may not have intended to provide lateral resistance. The load path shall be identified, taking into account the effects of any modifications, alterations or additions.
Where the available construction documents do not provide sufficient detail to characterize the structure, the evaluation may be based on field surveys, summarized in as-built drawings. These drawings must depict building dimensions, component sizes, reinforcing information (for concrete and masonry elements), connection details, footing information, and the proximity of neighboring structures. All parts of the building that may contribute to the seismic resistance or that may be affected by the seismic response of the structure must be identified. The field survey shall establish the physical existence of the structural members, and identify critical load bearing members, transfer mechanisms, and connections. The survey shall include information on the structural elements and connector materials and details. Performing the field survey will entail removal of fireproofing or concrete encasement at critical locations to permit direct visual inspection and measurement of elements and connections. Nondestructive techniques such as radiographic, electromagnetic and other methods may be used to supplement destructive techniques.
- Steel elements. Steel elements shall be classified by structural member type (e.g., rolled or build-up, material grade, and general properties). The survey shall note the presence of degradation or indications of plastic deformation, integrity of surface coatings, and signs of any past movement. For degraded elements, the lost material thickness and reduction of cross-sectional area and moment of inertia shall be determined. Visual inspection of welds shall be per American Welding Society D1.1, "Structural Welding Code-Steel." Structural bolts shall be verified to be in proper configuration and tightened as required in the AISC Steel Construction Manual. Rivets shall also be verified to be in proper configuration and in full contact, with "hammer sounding" conducted on random rivets to ensure they are functional. Nondestructive testing methods, such as dye penetrant and magnetic particle testing, acoustic emission, radiography and ultrasound shall be used when visual inspection identifies degradation or when a particular element or connection is critical to seismic resistance and requires further verification. For buildings in which archaic cast and wrought irons are employed, additional investigations to confirm ductility and impact resistance shall be conducted.
- Concrete elements. The configuration and dimensions of primary and secondary structural elements shall be established. The configuration and condition of reinforcing steel shall be assessed, through removal of concrete cover and direct visual inspection, and through nondestructive inspection using electromagnetic, radio-graphic and other methods. Critical parameters of the reinforcing system, such as lap splice length, presence of hooks, development within concrete, degree of corrosion and integrity of the construction shall be established in sufficient detail to perform the structural evaluation.
- Masonry elements. The configuration and dimensions of masonry elements shall be established. The configuration and condition of reinforcing-steel shall be assessed, through removal of masonry cover and direct visual inspection, and through nondestructive inspection using electromagnetic, radiographic and other methods. Critical parameters of the reinforcing system, such as lap splice length, presence of hooks, development within concrete, degree of corrosion and integrity of the construction shall be established in sufficient detail to perform the structural evaluation.
- Wood elements. The configuration and dimensions of wood elements; the connections between wood elements; and the connections between wood and other structural components or elements such as concrete or masonry walls shall be established. The configuration and condition of wood members, including size, type, grade, condition and quality shall be assessed, through removal of finish materials, and examination of unfinished areas such as attics, crawl spaces and basements. Critical connections and elements shall be visually inspected, using invasive procedures or removal of finishes where necessary. For shear walls, select locations shall be exposed to allow evaluation of sheathing material, nail size, spacing and installation (e.g., overdriven or nails that miss or split the framing members). The base connections of shear resisting elements shall be inspected and evaluated for their adequacy to connect the base of the structure to the foundation or structure below.
- Foundation elements. In the absence of dependable construction drawings, determination of the size and detailing of the foundation system requires invasive procedures. The evaluator shall select representative footings for exposure to establish footing size and depth. Conservative assumptions regarding the reinforcement may be made considering code requirements and local practice at the time of the design. In the absence of evidence to the contrary, it may be assumed that the foundation elements were adequately designed to resist actual gravity loads to which the building has been subjected.