- Docks, piers, gangways and catwalks, other than residential and farm docks and piers exempted from this chapter in the exceptions below, shall be designed by a registered design professional.
- All bulkheads having an exposed height greater than 5 feet (1525 mm) or with a superimposed load shall be designed by a registered design professional and require special inspection. Special inspection shall be waived for bulkheads of any height constructed from property line to property line of one- and two-family dwellings and including attachment to neighboring bulkheads.
- Oceanfront retaining walls, bulkheads and other types of retaining walls used by the public on the coastline of the ocean or adjacent inlets shall be designed by a registered design professional.
- Marine terminal or port facilities for berthing, mooring, docking and servicing ships, barges or tug boats that handle cargo of all types, including bulks, containers, liquids, fuels and people, which shall be designed by a registered design professional in accordance with accepted industry standards.
- Groins not exempted below, jetties, breakwaters, oceanfront seawalls, and oceanfront revetments which shall be designed by a registered design professional in accordance with accepted industry standards.
- Sill structures combined with marsh plantings and certain groins in accordance with the Department of Environmental and Natural Resources general permit requirements.
- Oceanfront and inlet sandbag revetments in accordance with the Department of Environmental and Natural Resources general permit requirements.
- Revetments constructed on single-family residential property having a height no greater than 10 feet and slope greater than 1.5 horizontal: 1.0 vertical and in accordance with the Department of Environmental and Natural Resources general permit requirements.
- Farm structures not on public waters.
- Piers and docks associated with one- and two-family dwellings meeting the exceptions of the North Carolina Residential Code.
BOAT SLIP. A berthing place for one or two watercraft where the watercraft can be securely moored to cleats, piling, or other devices while the boats are in the water. Boat slips are commonly configured as “side-ties” or as single- or double loaded “U” shaped berths.
BULKHEAD. A vertical wall structure designed to retain shoreline material and prevent erosion due to wave activity.
CATWALK. A narrow footway platform extending alongside a structure.
DESIGN WAVE. A wave that is potentially most damaging to an economically feasible structure, or wave for which a structure is designed.
DOCK. A structure extending alongshore or out from the shore into a body of water, usually accommodating multiple boat slips, to which boats may be moored in order to load or unload people or cargo, or to provide access to the water.
EXTRUSION. Manufacturing process whereby a material is pushed through a die to form a shape of constant cross section. Vinyl chloride sheet piling is generally manufactured using an extrusion process.
FETCH. Open water exposure over which waves are generated.
FIBER. One or more glass, carbon, or aramid filaments in the form of a continuous strand or roving in a fiber reinforce polymer (FRP) material.
FIBER ARCHITECTURE. Construction of a composite material from layers with different types and orientations of fibrous material.
FIBER ORIENTATION. Fiber orientation is the alignment of the longitudinal axis of a fiber in an FRP material with respect to the stated reference axis.
FIBER REINFORCED POLYMER (FRP). A polymeric composite material consisting of reinforcement fibers, impregnated with a fiber-binding polymer, such as glass, carbon, aramid, or hybrid combinations of these fiber types; which are then molded and hardened. Fiber-reinforced polymers are permitted to contain cores laminated between fiber-reinforced polymer facings.
FIBER VOLUME FRACTION. The volume of reinforcement fiber in a cured composite divided by the volume of the composite section.
FILLER. Substance added to the matrix of an FRP material intended to alter its engineering properties, performance, or cost.
GANGWAY. A footway bridge extending from the dock, pier, bulkhead or shore, usually to a floating structure.
GLASS TRANSITION TEMPERATURE (Tg). Temperature at which the polymer matrix of an FRP material changes from a glassy state to a rubbery state.
KING PILE. The primary structural member that supports horizontal panels to form a vertical wall sometimes used in bulkhead or groin construction.
LAMINA. A layer of fibers and resin in an FRP material.
MATERIAL LONGITUDINAL DIRECTION. Direction in an FRP material parallel to the direction of pultrusion (pulling) during the manufacture of a plate or structural shape.
MATERIAL TRANSVERSE DIRECTION. Direction in an FRP material orthogonal to the longitudinal direction.
MATRIX. Continuous constituent of an FRP material surrounding the reinforcing fibers and consisting of a polymer resin with any fillers and additives.
PIER. An elevated deck structure, usually pile supported, extending out into the water from the shore.
PILE. A timber, concrete, metal, or composite member embedded into the ground to support or brace a structure.
“Piles” or “piling” are plural forms of “pile.”
PRIVATE WATERFRONT STRUCTURES. A dock, pier, bulkhead, or associated structure not open to the general public and with no more than ten total boat slips and no more than ten owners.
PUBLIC WATERFRONT STRUCTURES. A dock, pier, bulkhead, or associated structure located on multi-family residential property (greater than ten dwelling units), public property or commercial property.
PULTRUSION. Manufacturing process whereby a material is pulled through a die to form a shape of constant cross section. FRP plates and structural shapes are generally manufactured using a pultrusion process.
RESIN. An organic polymer possessing indefinite and often high molecular weight and a softening or melting range that exhibits a tendency to flow when subjected to stress.
REVETMENT. A sloping structure usually constructed of stone or concrete and placed on a shoreline to protect it against erosion by wave and current action.
ROVING. In an FRP material, a roving is a large number of continuous parallel filaments or a group of untwisted parallel strands.
SHEET PILE. A pile with a generally slender flat cross section to be embedded into the ground or seabed and meshed or interlocked with like members to form a diaphragm, wall or bulkhead.
SYMMETRIC COMPOSITE. A symmetric composite is a composite material in which the sequence of lamina below the laminate mid-plane is a mirror image to those above the laminate mid-plane.
- Fixed piers, docks, catwalks—Private waterfront piers: 40 psf or 300 pounds concentrated load on any 2 foot by 2 foot (610 mm by 610 mm) area. Public waterfront piers: Design loads shall be the greatest combinations of loads exerted on the structure but not less than 60 psf or 300 pounds concentrated load on any 2 foot by 2 foot (610 mm by 610 mm) area.
- Floating docks—Private waterfront docks: 20 psf, public waterfront docks: 30 psf, or 300 pounds concentrated load on any 2 foot by 2 foot (610 mm by 610 mm) area. Under dead and live load, all floating docks shall have a minimum of 3 inches (76 mm) freeboard from the top of the flotation device, other than low freeboard watercraft (e.g. kayak) launching facilities. Floating docks with roofs shall have a minimum of 3 inches (76 mm) freeboard from the top of the flotation device under a combination of dead, snow and 75 percent of live load. All floating docks subject to this chapter shall have not more than 5 degrees tilt from the horizontal under uniform live loading on one-half of the dock width or under concentrated load of 400 pounds applied within 12 inches (305 mm) of any side.
- Gangways—Gangways shall be designed for a live load of 100 psf. Flotation for gangway landing shall be designed for 50 psf, live load.
- Bulkheads, revetments—Design loads shall be the greatest combinations of loads exerted on the structure. Consideration shall be given to horizontal loads exerted by superimposed loads on the retained earth and by inclined surface slopes. Superimposed loads shall be considered when exceeding 50 psf and located within a horizontal distance of three times the height of the bulkhead from the face of the bulkhead.
|LUMBER GRADE||MOISTURE CONTENT
2 Nominal Min.
|Surfaced Dry 19%|
|Guardrails||3B||3B||2 Nominal Min.||No. 2||No. 2||Surfaced Dry 19%|
|Wallcaps||3B||3B||2 Nominal Min.||No. 2||No. 2||Surfaced Dry 19%|
|Walers||3B||3B||4 × 6 Nominal||No. 2||No. 2||Surfaced Dry 19%|
|Cross Bracing||3B||3B||2 to 4 Nominal||No. 2||No. 2||Surfaced Dry 19%|
|Splash Zone||Split Pile Caps||4B||4B||2 to 4 Nominal||No. 2||No. 2||Surfaced Dry 19%|
|Stringers||4B||4B||2 Nominal||No. 2||No. 2||Surfaced Dry 19%|
|Sheet Piles||5B||4C||2 to 4 Nominal||Marine No. 1g||No. 2||Surfaced Dry 19%|
|Walers||5B||4C||4 × 6 Nominal||Marine No. 1g||No. 2||KD 20% or less
|Cross Bracing||5B||4C||2 to 4 Nominal||Marine No. 1g||No. 2||Surfaced Dry 19%|
|Not Allowedf||4C||6 × 6 Nominal||Not Allowedf||No. 2||KD 20% or less
|5Bf||4C||ASTM D25||ASTM D25||ASTM D25||KD 25% or Less|
|Glulam Timber||5B||4B||4 Nominal Min.||Note e||Note e||12% Average|
|5B||4B||31/2 Minimum||1.8E or Better||1.8E or Better||per manufacturer’s
- Lumber shall be pressure treated with preservative treatment in accordance with AWPA U1.
- At the discretion of the building official, lumber species other than Southern Pine may be approved when span tables for wet use conditions are submitted, and the lumber is treated for comparable service life to the treatment specifications required by Table 3605.3.
- Wood composite decking, treated or untreated, shall provide equivalent service life to the treated decking specified in Table 3605.3.
- All notches, holes, and field cuts shall be field treated in accordance with AWPA M4.
- Glulam grade shall be specified as a layup combination or stress class in accordance with the National Design Specification or the manufacturer’s published data. Layup combinations shall consist of species and grades capable of the treatment retentions equivalent to the AWPA use categories specified in Table 3605.3.
- Commercial pile wraps may be used to extend the life expectancy of timber piles exposed to marine borers.
- AWPA requirements for Marine No. 1 specify that no heartwood be exposed on any face prior to preservative treatment.
|Notch Impact Resistance||ASTM D256||2.0 ft-lb./in
|Drop Dart Impact Resistance,
|ASTM D4226||1.0 in-lb./mil
|Drop Dart Impact Resistance,
|ASTM D4226||2.0 in-lb./mil
|Tensile Strength||ASTM D638||6500 psi
|Modulus of Elasticity in Tension||ASTM D638||377,000 psi
under 264 psi
|Linear Coefficient of Expansion||ASTM D696||4.4 × 10-5 in/
|Glass Transition Temperature Tg||D4065||5|
|Coefficient of Thermal Expansion||D696||5|
|Moisture Equilibrium Content||D570||5|
|Longitudinal Tensile Strength||D638||10|
|Transverse Tensile Strength||D638||10|
|Longitudinal Tensile Modulus||D638||10|
|Transverse Tensile Modulus||D638||10|
|Longitudinal Compressive Strength||D6641||10|
|Transverse Compressive Strength||D6641||10|
|Longitudinal Compressive Modulus||D6641||10|
|Transverse Compressive Modulus||D6641||10|
|Longitudinal Flexural Strength||D790||10|
|Transverse Flexural Strength||D790||10|
|Longitudinal Flexural Modulus||D790||10|
|Transverse Flexural Modulus||D790||10|
|In-Plane Shear Strength||D5379||10|
|In-Plane Shear Modulus||D5379||10|
|Inter-laminar Shear Strength||D2344||10|
|Longitudinal Pin Bearing Strength||D953b||10|
|Transverse Pin Bearing Strength||D953b||10|
|Pull Through Strength per Fastener
t = 3/8″
t = 1/2″
t = 3/4″
|D7332, Proc. B||10|
- Property requirements for shapes apply to sheet piles.
- Tests shall be conducted for material thicknesses, t, tabulated and bolt sizes from 3/8 inch to 1 inch in diameter. No more than one-third of the bolt shank within the thickness of the connection material may be threaded. Bolts shall be installed snug tight.
- Performance criteria for the structure;
- Intended service life of the structure;
- Expected environmental conditions, including likelihood of exposure to alkalis or organic solvents;
- Protective measures; and
- Feasibility of maintenance and repair during service.
- Water: Samples shall be immersed in distilled water having a temperature of 100 + 30F and tested after 1,000 hours of exposure.
- Alternating ultraviolet light and condensing humidity: Samples shall be exposed according to Cycle No. 1 (0.89 W/m2/mm, 8 hours UV at 600C, 4 hours condensation at 500C) using UVA-340 lamps in an apparatus meeting the requirements of ASTM G154. Samples shall be tested within two hours after removal from the apparatus.