Numerical simulation method and parametric study of a novel rocking steel truss for improving the seismic performance of the existing buildings

Abstract

This paper proposes a measure of reinforcing concrete frames with rocking steel truss to strengthen an existing building and reduce future seismic loss without excessively increasing reinforcing costs. The particular rocking and dissipating construction of the bottom joint of the rocking steel truss enables it to improve the lateral deformation mode of the RC frame, to dissipate the input energy of the earthquake, and to recentre the frame after the earthquake. First, the configurations of the truss and rocking joints are presented, and the rocking mechanism of the truss is illustrated. Secondly, the numerical method for modelling the rocking steel truss is proposed and realised in OpenSees. Lastly, a three-story school building is taken as a case, and the influences of the added rocking truss on the seismic performances of the structure are discussed by considering three factors, including stiffness of the steel truss, friction force, and prestressed force. Then the optimal design of the rocking steel truss is determined, and the seismic performances of the RC frame with and without rocking steel truss are compared. The results show that the truss stiffness, friction force, and prestressed force significantly affect the seismic performance of the structure with rocking steel truss. The lateral distribution mode of RC frame is improved by adding the rocking steel truss, and maximum drift and residual drift can be reduced by 66.93% and 98.15%, respectively.