Design and Implementation of Seismic Retrofitting of a Steel Bridge: Case study of Karim-Khan-Zand bridge in Tehran

Abstract

In order to achieve the maximum utilization of the roadways as well as increasing the service life of the bridges, proper traffic transfer, earthquake resistance and damage resistance of the bridges caused by the passage of time; strengthening and repairing of the bridges are essential. In this study, Karim-Khan bridge was selected as a case study to be repaired and retrofitted. The dynamic response of this bridge was investigated by structural finite element analysis method using SAP2000 software. The three-dimensional geometry of the bridge developed through the software environment and advanced options such as the base contact elements and nonlinear material properties were used to assess the effect of different seismic loads on the structural behavior of the critical bridge components. C / D ratio showed that the columns are not ductile due to geometric configuration when subjected to axial load; while their sections in the longitudinal direction are weak in bending. For this reason, the columns are more vulnerable to collapse during the earthquake. Hence it was concluded that the seismic vulnerability of the bridge is high. Regarding the cost of rehabilitation, which was about 30% of the cost of construction of a new bridge and the traffic problems during the construction of the new bridge, the option of improvement and rehabilitation was approved by the technical and civil deputy of Tehran Municipality.