Seismic Design and Testing of an RC Slab-Column Frame Strengthened by Steel Bracing

This study is concerned with developing a rational design procedure for use of ductile steel bracing for strengthening existing seismically “weak” RC slab-column building structures. A one-third scale, two-bay, two-story RC slab-column frame model was selected to represent existing seismically inadequate structures of its type. The design procedure, construction and test results of the steel bracing system for strengthening the RC frame are presented in this paper. The strengthened frame was subjected to a combination of gravity and cyclic lateral loads up to 2% overall frame drifts. The behavior of the strengthened frame improved dramatically over that of the bare RC frame. A maximum 2.75% drift in the first story was reached which is highly probable during severe earthquake motions.