Pulse-like effects of near-fault earthquakes on reinforced concrete buildings in Mandalay city, Myanmar

Abstract

The behavior of the earthquake ground motions recorded at the locations a few kilometers away from the active faults is significantly different from the ordinary ground motions. It may contain the velocity pulse, which brings the seismic energy in a single large pulse of motion. Mandalay city is selected as the studied site area, located about 8 kilometers away from the Sagaing Fault. Under the seismic hazard condition of Mandalay, three types of reinforced concrete buildings - 4-story, 10-story, and 16-story buildings are studied to represent the low-rise, median-rise, and high-rise buildings respectively. These buildings are subjected to the ground motions recorded from far-field and near-fault earthquakes using the Nonlinear Response History Analysis (NLRHA) in comparison with the seismic response of the linear analysis methods such as Equivalent Lateral Force (ELF) analysis and Response Spectrum Analysis (RSA). The effects of ground motion selection methods are also studied through the comparison of the two Tall Initiative (TBI) guidelines - TBI (2010) and TBI (2017). The Interstory Drift Ratios (IDR) of the buildings are higher in the near-fault ground motions and it is more pronounced in fault-normal direction when compared to the fault-parallel direction. The pulse period (Tp) observed in the near-fault ground motions are interrelated to the fundamental period of the buildings (T1) in determining the structural response of the buildings. The TBI (2017) uses more meaningful and accurate intensity measure (IM) in the ground motion selection and produces less seismic demand when compared to the TBI (2010).