Structural Tests of Precast, Prestressed Concrete Deck Panels for California Freeway Bridges

摘要

Full-scale structural tests of five precast, prestressed concrete bridge deck panels have been carried out in simple bending to failure at the San Diego State University Structural Engineering Laboratory in San Diego, Calif. The purpose of the tests was to demonstrate to Caltrans that the precast concrete panels act compositely in flexure with a cast-in-place topping slab so that they can be used for California ,q bridges. To ensure that the full deck width was active in resisting the applied loads, steel I-beams the width of the deck were used under the load and at the reaction points. Neoprene bearing pads were incorporated at the supports to allow free rotations at the deck ends. Each bridge deck consisted of a precast, prestressed concrete deck panel with a cast-in-place topping slab, with no reinforcing bars crossing the interface between slabs. Of particular interest was the verification that no horizontal shear slip occurred between the two slabs and that the deck acted as a fully composite member to failure. One test featured the precast concrete slab by itself, three of the tests investigated the deck behavior in positive bending with different roughening levels applied to the top of the precast concrete slab, and the fifth test was performed in negative bending (upside down). Nonlinear prediction analyses were conducted for each of the tests, including the formation and spreading of flexural cracking along the deck and plastic hinging at the critical section in the center of the span. Test results, supported by detailed structural analyses, demonstrated that there was no horizontal shear slip between the precast concrete panels and cast-in-place slabs, allowing them to respond in flexure as a single composite slab.