Soil-structure Interaction In Railway Bridges

Railway bridges are an important component of railway infrastructure. They require huge amount of costs in their both construction and maintenance. Railway bridges are also considered as bottle necks of the rail transportation system. In case of any problem with railway bridges, it can stop the railway operations. In this study, a research was made on the soil-structure interaction of the Weiherfeld railway bridge in Karlsruhe, Germany. The Weiherfeld bridge was built in 1908. The bridge is made of steel, bolded construction and three-span frame with 27 m wide, 54.90 m long and 5 m height. There are 560 trains and additionally shunting movements travelling on the bridge per day. In this study, the structural behavior of Weiherfeld bridge was analyses under freight and passenger trains for a while and in addition soil stress and strain analyses were performed considering the loads coming from the bridge structure. For this purpose, the structural model of the bridge was created with the SAP 2000 finite element program and the loads were defined in the program as the moving loads considering the axle loads and speeds of the passenger and freight trains. In this loading scenario, the loads and deformations occurring in the bridge beams and columns are calculated. Later on, a continuously soil structure was modeled in the PLAXIS program under the piers of bridges by taking into consideration various soil structure types (such as sandy, clayey, rocky etc.). The dynamic loads obtained from the SAP 2000 program were transferred to the soil model created in the PLAXIS program and various soil-structure analyses were performed. Finally the effects of soil-structure were evaluated considering the railway superstructure.