Experimental and Analytical Study on the Proposed Retrofit Method for Concrete Bent in Ordinary Highway Bridges in Iran

AbstractIn recent years, particularly after the occurrence of strong earthquakes, there is an increased need for seismic retrofit of present bridges and changes in the design of new bridges. A method for retrofitting concrete bents in bridges involves the use of steel sheets or profiles to apply the confinement force. In this study, two specimens were analyzed in the laboratory at the scale of 30% under constant gravity and lateral cyclic loading. Also, a finite-element model was used to compare the behavior of experimental specimens. The first specimen was a model of a typical as-built bridge in Iran as generally designed by the common regulations of the 2000s, and the other specimen was a retrofitted model of the same frame in which transverse and longitudinal confinement in the connection region was used. The results show that the retrofit method will improve most of the frame seismic behavior indices, such as the performance level, absorbing energy in hysteresis curves, ductility, modification of failure propagation, and formation priority of plastic hinges.