Strengthening RC Frames against Disproportionate Collapse by Post-Tensioning Strands

Extensive studies had been carried out to understand the load resisting mechanisms and load re-distribution behavior of reinforced concrete (RC) frames to resist disproportionate collapse. It is found that RC frames with irregular layout or longer design span have high vulnerability for collapse. Thus, it is necessary to look for measures to improve the robustness of the frames against disproportionate collapse. Post-tensioning strand (PTS) is one of the strengthening approaches. Thus, a series of experimental and analytical studies are carried out to quantify the efficiency of PTS for upgrading the load resisting capacity of RC frames. The test results including load-displacement curves, deformation shape, and local strain are captured. In addition, the load resisting capacity of PTS in different load carrying stages is evaluated. The change of the failure modes due to externally installed PTS is also determined.