1808.2.17 Protection of Pile Materials

Where boring records or site conditions indicate possible deleterious action on pier or pile materials because of soil constituents, changing water levels or other factors, the pier or 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. The following specific provisions shall apply:

1. Untreated timber piles shall not be used unless the top level of the pile is below the permanent water table. The permanent water table level shall not be assumed higher than the invert level of sewer, drain, or subsurface structure in the adjacent streets, nor higher than the water level at the site resulting from the lowest drawdown of wells or sumps, but in no case shall untreated timber piles be used where the cut-off level is less than 10 feet (3048 mm) below the adjacent legal grade. Where treated piles are required, preservative treatment shall consist of impregnation with creosote or a creosote solution or CCA treatment. For piles entirely embedded below grade, a pentachlorophenal solution may be used. Treatment shall be in accordance with all requirements of the AWPA standards and as specified in Section 1809.1.2.
2. Piles installed in ash or garbage fills, cinder fills, and piles that are free-standing in or near a seawater environment, or that are used for the support of chemical plants, coal piles and piles under similar conditions of chemical seepage or aggressive action, or 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.

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 their 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 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 twenty 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.

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, shall 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 shall have sufficient rigidity to prevent "whip" during driving.