Seismic Performance of Two-Column Bents—Part II: Retrofit with Infill Walls

As part of an ongoing study on seismic behavior of 2-column bents built before the 1970s, the effectiveness of an infill wall as a retrofit technique was evaluated. Experimental work was conducted on 1/4-scale models using the shake tables at the University of Nevada, Reno. Caltrans current construction practice was implemented in the retrofit. The wall had a gap between the top of the wall and the bottom of the cap beam, which modified the lateral load path and caused the wall and columns to partially separate. Deterioration of the structure was concentrated in the cap beam and top of the columns. The overall performance of the infilled bent was significantly improved in terms of the displacement ductility capacity and the lateral load strength. A simple model was developed based on experimental results to determine the force-displacement curves of infilled bent.