Comparison Study on Seismic Performance of Different Structural Forms for Urban Expressway Viaducts

Many structure forms can be chosen when designing an urban expressway viaduct. To get an optimal structure, a comparison study on the seismic performance of different structural forms for urban expressway viaducts should be done carefully. Taking multi-span, simply-supported, small box girders as a basic structure type, a double column pier and double pile cap structure (DCPDPC), adouble column pier and single pile cap structure(DCPSPC), and a single column pier and single pile cap structure (SCPSPC) were chosen as substructures of the same bridge. Seismic performances — such as deformation capacity of bearings, bending capacity and shearing capacity of piers and piles in common earthquakes, and ductile capacity of piers under rare earthquakes of different structural forms — were compared by the demand capacity ratio method. The optimal structures are discussed herein. It can be concluded that the structural form of DCPDPC and DCPSPC have better advantages than others, and the SCPSPC has poor seismic performance and should be carefully used when designing an urban expressway viaduct. This research provides good technical support for the conceptual design for urban expressway viaducts.