PREDICTING THE PEAK SEISMIC RESPONSE OF A RETROFITTED NINE-STOREY STEEL REINFORCED CONCRETE BUILDING WITH STEEL DAMPER COLUMNS

A steel damper column using low-yield strength steel is an attractive choice for the seismic retrofitting of existing buildings because it does not introduce architectural problems, unlike braces and walls. In a seismic retrofit design using a steel damper column, the design of the connection joint between the damper column and the existing concrete member is very important. The designer needs to evaluate the maximum shear force and moment of the joint, in addition to the peak storey drift and member forces. In this study, the nonlinear peak response of a retrofitted nine-storey steel reinforced concrete building with steel damper columns was analytically investigated. A steel damper column was added on the side of the exterior frame by connection joint, using mortar, anchors, and studs. The peak response was predicted using nonlinear static (pushover) analysis, the peak storey drift, and the maximum moment and shear force at the connection joint, and the results were compared with the results obtained by nonlinear time-history analysis. Thus, it was revealed that the predicted peak storey drift, the maximum shear force, and moment at the connection joint are in good agreement with the time-history analysis results. The largest shear force of the anchor in the connection joint was also evaluated and compared with the time-history analysis results.