Seismic Performance Evaluation of Reinforced Concrete Special, Intermediate and Ordinary Moment Resisting Frame Buildings

摘要

ACI318-05 code, the building code requirements for structural concrete, contains provisions for three different levels of ductility for moment resisting frames (MRFs) named special (SMRF), intermediate (IMRF) and ordinary (OMRF) types. In this paper, the ductility of these three systems is quantified in order to observe the differences in performance. Three two-bay reinforced concrete (RC) moment resisting frame (MRF) buildings with mentioned levels of ductility and three different heights (five, nine and fifteen storey buildings) are modeled and designed with special attention to chapter 21 of ACI318-05. The key difference among different types of MRFs is the difference in transverse reinforcement arrangement. Variety in configuration of transverse reinforcement leads to different confinement. Mander model was applied to determine the behaviour of each member and the results are compared with the modelling parameters of available code's provisions. In order to evaluate the performance of the buildings, pushover analyses have been conducted according to ATC40 and FEMA-356 and comparisons are made among the capacity of structures. In addition, nonlinear dynamic time history analyses have also been performed according to FEMA-356 using different ground excitation e.g. Imperial Valley spectrum. The development of plastic hinges has been monitored and comparisons are made using diagrams of story drifts and absolute roof displacements.