广西乡镇供水工程设计提纲.doc

Rising labor and materialcosts, a post-recession short-age of skilled labor, andtighter construction sched-ules and budgets—all havecontributed to the need to developlabor-efficient forming systems forall concrete construction. In the caseof cast-in-place multi-level parking structures,perhaps the best answerto labor-efficient form-ing is post-tensionedconcrete, which allowsconstruction of long,column-free spans read-ily adaptable to theunique framing andfunctional require-ments of these struc--concreteflat plate or flat slab de-sign is sometimes usedfor parking structures,particularly in under-ground forming of theseflat plate or slab designsis traditionally sup-ported with hand-setshoring, which is laborintensive and conse-quently leads to higherconstruction costs. Although im-proved hand-set deck forming sys-tems developed in Europe have beenintroduced in the past 15 to 20years, hand setting of these systemsis still labor -tensioned parking structuresare a labor-efficient alternative toflat plate or slab designs. The verynature of post-tensioned design al-lows for long-span slender beamswith relatively thin one-way deckslabs spanning between the widths for a 6-inch-thick slabare typically 17 to 22 feet. Typicalsupport beams are 50 to 60 feetForming concreteparking structuresefficientlyBYDAVIDJ. GOWERSThe use of an all-steel beam form system and post-tensioned concrete canmaximize labor efficiency and minimize project costsAll-steel beam forms are set up for a garagepour. Ledgers will be set in place on theshoring frames to support deck forms thatspan between the beam forms without addi-tional , with a 14x36-inch only a small increase in slabthickness, bay widths up to 28 feetare possible, and they can be sup-ported by the same size post-ten-sioned beam all-steel beam forms A contractor who plans to buyforming equipment for parkingstructures needs to choose a b