ASSESSMENT AND RETROFIT OF FULL-SCALE MODELS OF EXISTING RC FRAMES

Abstract

Pseudo-dynamic (PSD) tests on two full-scale models representative of existing non-seismic resisting RC frame structures are described. The testing program covered several aspects, namely the assessment of seismic performance of existing frames without and with infill panels, retrofitting of a bare frame using Selective Retrofitting techniques, strengthening of infill panels using shotcrete and retrofitting of frames using K-bracing with shear-link dissipators. The main results from the PSD tests are summarized and discussed and conclusions are drawn. The tests on the bare and infilled frames showed the high vulnerability of existing structures constructed in the 60's and confirmed the beneficial effects of infill panels. Important improvements, in terms of seismic performance, were achieved by retrofitting of the frames. However, strengthening of the existing infill panels in poorly detailed frames may lead to dangerous 'local' failures, such as shearing out of the external columns.