Seismic Design Evaluation of Reinforced Concrete Buildings for Near-Source Earthquakes by Using Nonlinear Time History Analyses

摘要

Seismic design codes mostly claim that their requirements lead to Life Safety (LS) Performance Level (PL) for buildings. This is while many buildings, designed based on the current codes have shown unacceptable performance, and even have collapsed in some recent earthquakes, particularly near-source events. On this basis, it seems that the code provisions still need further improvement to create sufficient confidence in the engineering community. This study has been conducted to find out how IBC 2009 And ACI 318-2014 codes are effective in providing the LS PL in reinforced concrete multi-story regular buildings with special moment frame lateral load bearing system. For this purpose, a set of multi-story buildings up to 16 stories were considered in the highest seismic hazard zone of Tehran, and were designed based on the codes. Then, a set of near-source three-component accelerograms were employed and scaled according to the code, and a series of nonlinear time history analyses were conducted for all buildings. Roof displacement and acceleration, and base shear forces were calculated, and also the formation trend of plastic hinges and their distribution in the structures were investigated for evaluating the seismic performances. Results show that for some earthquakes the buildings performance exceed LS PL, and even in some cases they reach collapse level.