Nonlinear sensitivity analysis of reinforced concrete frames

Design sensitivity analysis is a necessary task for design optimization of structures. Methods of sensitivity analysis for linear systems have been developed and well documented in the literature; however there are a few such research works for nonlinear systems. Nonlinear sensitivity analysis of structures under seismic loading is very complicated. This paper presents an analytical sensitivity technique for reinforcement concrete moment resisting frames (RCMRF) that accounts for both material nonlinearity and geometric effects under pushover analysis. The results of the proposed method are compared with the results of finite difference method (FDM). Two examples including one three-story, two bays moment frame and one ten-story, two-bay frame are used to illustrate the efficiency and accuracy of the method and difficulties of the FDM for nonlinear sensitivity analysis (NSA) of RCMRF are discussed. The proposed technique can be very useful and efficient for optimal performance-based design of RC buildings.