Drift and Response Reduction Factor of RC Frames Designed with DDBD and FBD Approach

摘要

Performance-based seismic evaluation of 2-, 4-, 8- and 12-story RC frames designed using direct displacement-based design (DDBD) and convectional force-based design (FBD) approach as per Indian standards is carried out. The DDBD approach is implemented for the design of RC frames using IS 1893 spectrum. The capacity curve and the performance point of designed RC frames are obtained by analyzing frames using nonlinear static pushover analysis. The response reduction (R) factor of designed RC frames as per FBD and DDBD method is evaluated from the bilinear idealization of capacity curve. The designed moment resisting RC frames are analyzed using nonlinear time-history analysis (NLTHA) to investigate the damage index in the form of lateral drift profile. Comparison of the NLTHA results in terms of inter-story drift ratio (IDR) and nonlinear static analysis results in terms of performance point and the response reduction (R) factor for RC frame buildings indicates the efficiency of the DDBD approach. The values of 'R' factor of RC frames designed with DDBD approach are observed higher than that of similar frame designed using FBD approach, indicating higher dissipation of energy through the nonlinear behavior of DDBD frame. The result shows that the building height is a crucial parameter affecting the 'R' factor of RC frame. The RC frames designed with DDBD approach are observed comparatively economical as compared to designed using FBD approach. The IDR of RC frames designed with DDBD approach is observed relatively higher than that of similar frames designed with FBD approach.