Decision Of Retrofit Schemes With Viscous Dampers For Non-ductile RC Frames Based On Seismic Fragility

In previous earthquake events, it has been reported that a number of existingnon-ductile RC frames experienced severe damage or even collapse. Use viscousdampers retrofit non-ductile RC frames can increase the energy dissipation capacityof RC frame structures and improve the seismic performance of RC structures.Therefore, in this thesis we design several retrofit schemes with nonlinear viscousdampers, then use fragility curve to evaluate the schemes. The main contents are asfollows:(1) Select several different heights non-ductile RC frames then design viscousdampers retrofit schemes based on performance-based seismic design. Set up finiteelement models of the RC frames before and after retrofitting based on OpenSeessotfware. Use time history analysis to measure the performances of differentschemes and to study the viscous dampers’ performance in various situations.(2) Select Saas ground motion intensity parameters, maximum drift angle θmaxas seismic demand parameters, using the method of cloud to evaluate before andafter the viscous dampers probabilistic seismic reinforcement requirements analysis,taking into account in the analysis of ground motion uncertainty.(3) Select three regulation limit states recommended by FEMA as inter-storydrift limits. Base on probabilistic seismic demand analysis of different story driftlimit states use analytical methods to obtain the fragility curves of RC frames beforeand after retrofitting, finally make decisiongs from the perspective of probability.(4)Anti-collapse is the most serious problem for non-ductile RC framestructures, to measure this problem we use the vulnerability analysis method basedon IDA. Non-ductile RC frames and viscous dampers reinforced structures wereanalyzed and got IDA structural collapse fragility curves. According to structuralfragility curves give the final decision viscous damping reinforcement schemes.