LARGE SCALE TESTS ON NAVY REINFORCED CONCRETE PIER DECKS STRENGTHENED WITH CFRP SHEETS

摘要

An aging waterfront infrastructure, changing mission requirements, and increasing budget constraints are forcing the U.S. Navy to consider upgrades as an alternative to replacement of waterfront facilities. The Naval Facilities Engineering Service Center (NFESC) is studying the use of fiber reinforced plastics (FRP) to upgrade existing reinforced concrete piers and wharves. Carbon fiber reinforced plastic (CFRP) sheets are bonded to the underside of reinforced concrete pier decks to increase their structural capacity, in particular to resist large patch loads from mobile crane outrigger floats. Laboratory tests of under-reinforced one-fifth scale slabs were conducted to determine the effects of upgrading on moment capacity, shear strength, deflection, ductility and failure mode. Nonlinear finite element analyses predicted the deck's test response beyond steel yielding and concrete crushing. Large (one-half) scale tests were conducted on a reinforced concrete pier (Advanced Waterfront Technology Test Site) in Port Hueneme, California. The half scale slabs were 3 m (10 ft) by 5.5 m (18 ft) with a thickness of 23 cm (9 in).rnBoth laboratory and field control specimens confirmed the expected punching shear failure mode. Laboratory specimens reinforced with one CFRP layer in each direction exhibited an ultimate load increase of up to 47%. Control half-scale slabs failed around 228 kips, while the upgraded half-scale slabs (with three longitudinal and one transverse CFRP layers) resisted up to 274 kips, a 20% increase. CFRP reinforced slabs showed a ductility comparable to that of the control slabs.