28 July 2005
Fiberglass-reinforced plastics (FRP), ultra-high molecular weight (UHMW)
plastics, and other new materials should be governed by the accepted industry
standards for structural design and detailing.
DECK STRUCTURE DESIGN.
Concrete is generally considered the best material for deck framing and should
be used for most pier and wharf decks. Although timber, steel, steel/concrete
composite, and timber/concrete composite decks have been used in the past,
they are neither cost-effective nor suitable for the high concentrated load
capacities currently demanded of decks. From durability, maintenance, and life-
cycle-cost viewpoints, a concrete deck is superior and is highly recommended.
The deck framing should be slabs supported on pile caps, using an all cast-in-
place, all precast, or composite construction, as shown in Figure 4-1. For the
concentrated loads which typically control the deck design, a solid slab with its
high punching shear resistance is recommended. Framing systems using thin
slabs, as in cast-in-place slab/beam/girder systems, should not be used because
of the tendency to spall along beam/girder corners and edges. Occasionally,
where high concentrated loads are not specified, voided slabs may be used.
Map cracking in the cast-in-place topping at the precast panel joints is sometimes
seen. To control the cracking, transverse post-tensioning is sometime utilized.
For distribution of horizontal loads, pier and wharf decks should be continuous,
with as few expansion joints as possible. Where expansion joints are needed,
the deck on each side of the joint should be supported on a separate pile cap or