tailieunhanh - Expansion Joints

Expansion Joints Introduction General Design Criteria Jointless Bridges Small Movement Range Joints Sliding Plate Joints • Compression Seal Joints • Asphaltic Plug Joints • Poured Sealant Joints • Design Example 1 25 Medium Movement Range Joints Bolt-Down Panel Joints • Strip Seal Joints • Steel Finger Joints • Design Example 2 Ralph J. Dornsife Washington State Department of Transportation Large Movement Range Joints Modular Bridge Expansion Joints • Design Example 3 Construction and Maintenance Introduction Expansion joint systems are integral, yet often overlooked, components designed to accommodate cyclic movements. Properly functioning bridge expansion joint systems accommodate these movements without imposing significant secondary stresses on the superstructure | Dornsife . Expansion Joints. Bridge Engineering Handbook. Ed. Wai-Fah Chen and Lian Duan Boca Raton CRC Press 2000 25 Expansion Joints Introduction General Design Criteria Jointless Bridges Small Movement Range Joints Sliding Plate Joints Compression Seal Joints Asphaltic Plug Joints Poured Sealant Joints Design Example 1 Medium Movement Range Joints Bolt-Down Panel Joints Strip Seal Joints Steel Finger Joints Design Example 2 Ralph J. Dornsife Large Movement Range Joints Washington State Department Modular Bridge Expansion Joints Design Example 3 of Transportation Construction and Maintenance Introduction Expansion joint systems are integral yet often overlooked components designed to accommodate cyclic movements. Properly functioning bridge expansion joint systems accommodate these movements without imposing significant secondary stresses on the superstructure. Sealed expansion joint systems provide barriers preventing runoff water and deicing chemicals from passing through the joint onto bearing and substructure elements below the bridge deck. Water and deicing chemicals have a detrimental impact on overall structural performance by accelerating degradation of bridge deck bearing and substructure elements. In extreme cases this degradation has resulted in premature catastrophic structural failure. In fulfilling their functions expansion joints must provide a reasonably smooth ride for motorists. Perhaps because expansion joints are generally designed and installed last they are often relegated to peripheral status by designers builders and inspectors. As a result of their geometric configuration and the presence of multiple-axle vehicles expansion joint elements are generally subjected to a significantly larger number of loadings than other structural members. Impact a consequence of bridge discontinuity inherent at a joint exacerbates loading. Unfortunately specific expansion joint systems are often selected based upon