tailieunhanh - Bridge Decks and Approach Slabs

Bridge Decks and Approach Slabs Michael D. Keever California Department of Transportation Introduction Bridge Decks Cast-In-Place Reinforced Concrete • Precast Concrete Bridge Decks • Steel Grid Bridge Decks • Timber Bridge Decks • Steel Orthotropic Bridge Decks John H. Fujimoto California Department of Transportation Approach Slabs Structural Design Considerations • Settlement Problems • Additional Considerations Summary Introduction This chapter discusses bridge decks and structure approach slabs, the structural riding surface that typically is the responsibility of bridge design engineers when developing contract plans and details | Keever . Fujimoto . Conceptual Bridge Design. Bridge Engineering Handbook. Ed. Wai-Fah Chen and Lian Duan Boca Raton CRC Press 2000 24 Bridge Decks and Approach Slabs Michael D. Keever California Department of Transportation John H. Fujimoto California Department of Transportation Introduction Bridge Decks Cast-In-Place Reinforced Concrete Precast Concrete Bridge Decks Steel Grid Bridge Decks Timber Bridge Decks Steel Orthotropic Bridge Decks Approach Slabs Structural Design Considerations Settlement Problems Additional Considerations Summary Introduction This chapter discusses bridge decks and structure approach slabs the structural riding surface that typically is the responsibility of bridge design engineers when developing contract plans and details. Decks and approach slabs are usually not specially designed for each bridge project but are instead taken from tables and standard plans either developed and provided by the owner or approved for use by the owner. However as the load and resistance factor design LRFD is adopted by various agencies standards that were developed previously must be reviewed and revised to comply with these new standards. Not only do decks and approach slabs provide the riding surface for vehicular traffic but they also serve several structural purposes. The bridge deck distributes the vehicular wheel loads to the girders which are the primary load-carrying members on a bridge superstructure. The deck is often composite with the main girders and with reinforcement distributed in the effective regions of the deck serves to impart flexural strength and torsional rigidity to the bridge. The structure approach slab is a transitional structure between the bridge which has relatively little settlement and the roadway approach which is subject to varying levels of approach settlement sometimes significant. The approach slab serves as a bridge between the roadway and the primary bridge and is intended to reduce .