Plywood cushion blocks for
precast concrete piling
Precast concrete piles are a good choice for certain applications. They are ideal when they can be driven to tip elevation and do not have to be cut. However, cutting the piles is a fairly simple task. Extreme care must be taken while handling and cutting the waste sections.
the wood shows signs of being highly compressed, delaminated or burned
it should be replaced. It may be necessary to change the plywood
cushion if it starts to fail. This should be done before the pile
reaches final tip elevation or blow count. A new cushion should
used on every pile. The cushion may look usable, but it is
and likely has an impression from the previous pile that will not
fit to the next pile. This could cause pile breakage.
The job photos show that with proper methods the precast concrete piles can be handled and driven efficiently and without problems occurring.
These piles were driven at a Brooklyn, New York pier by Contractor Spearin Preston & Burrows from a barge using a Manitowoc 4100 crane and an ICE 42S 42,000 ft/lb. hammer. The piles are 65-70' 16" X 16" square prestressed. The pier is being constructed for the NYC Economic Development Corporation.
The plywood cushions were fabricated by DFP Foundation Products, LLC., Franklin Lakes, NJ 201-337-5748. FAX 201-337-9022.
For more information on this subject contact the Prestressed Concrete Institute and ask about the PCI Committee on Prestressed Concrete Piling report titled: "Recommended Practice for Design, Manufacture and Installation of Prestressed Concrete Piling." This report was published in the Mar/April 1993 PCI Journal.
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