Graduate Student, Department of Civil, South Tehran Branch, Islamic Azad University, Tehran, Iran
Assistant Professor, Department of Civil, South Tehran Branch, Islamic Azad University, Tehran, Iran
The aim objective of this study is to investigate the effects of near-field earthquakes on the response of mid-rise buildings with tubular structure. For this purpose, a 20-story building with a square plan of six by six bays, all with 6 m span, and story height of 3.70 m is considered. Axial force of columns, shear lag, and inter-story drift values are used as the main response parameters. Nonlinear time history analyses (NLTHA) of the considered building were conducted by using once the two-component, and once more three-component accelerograms of both far- and near-field selected earthquakes for comparison. Numerical results of NLTHA show that inclusion of a vertical component of ground motion leads to around 17% and 32% increase, in average, in axial forces of side and corner columns respectively in case of far-field earthquakes. These increases were respectively 22% and 37% in case of near-field earthquakes. The vertical ground motion also leads to around 11% and 15% increase, in average, in shear lag of side and corner columns respectively in case of far-field earthquakes, and 13% and 19% increase in case of near-field earthquakes. The amount of increase in inter-story drift values due to the vertical ground motion was observed in range of 24% and 27% for far- and near-field earthquakes respectively.