Adaptive linear analysis for inelastic seismic design of reinforced concrete moment frames

An adaptive linear analysis method for inelastic seismic design of reinforced concrete moment frames is developed adopting the well-known concept of incremental linear approximation for non-linear analysis. A series of linear analyses are performed for multiple lateral loading steps. After performing the linear analysis for each loading step, the analysis model of the structure is modified for the linear analysis of the next loading step addressing the current distribution of plastic hinges. By simply summing up the results of all piecewise linear analyses, the inelastic force and deformation demands of the members are directly determined. The proposed method is applied to the inelastic seismic design of regular and irregular reinforced concrete special moment frames and the design results are verified by comparing with the results of non-linear analysis. The adaptive linear analysis, which is aimed at application to the preliminary seismic design where the non-linear analysis is not preferred, can directly account for the effects of inelastic behaviour such as plastic mechanism of structure, moment redistribution between members and plastic deformations of members.