Although buildings are excited by translational and rotational earthquake components, only translational components are considered in seismic loads. The effects of earthquake torsional components on building responses were studied in this work. For this purpose, the torsional component of 14 earthquakes was extracted from their translational components. Symmetric and asymmetric idealised single-storey models were analysed by considering the torsional and translational components. The models considered five different values of the uncoupled torsional frequency to uncoupled translational frequency ratio (Ω = ω_θ/ω_x = 1·5, 1·25, 1, 0·75, 0·5), with their lateral period varying from 0·05 to 2 s. The displacements of the left-hand side, right-hand side and centre of the diaphragm, the diaphragm rotation about the centre of mass and the base shear were studied. The results indicated that the effect of the torsional component on the non-linear responses of the building was considerable, and ignoring this effect led to an underestimation of the responses. The increase in the building's responses due to the torsional component was found to depend significantly on the value of Ω and the stiffness eccentricity. The maximum growth of the displacement of torsionally stiff and torsionally flexible buildings was 51% and 155%, respectively. The diaphragm rotation can be increased to 154% in the asymmetric systems.

中文翻译：

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地震扭转分量对对称/非对称建筑物响应的影响

尽管建筑物受到平移和旋转地震分量的激励，但在地震荷载中仅考虑平移分量。在这项工作中，研究了地震扭转分量对建筑物响应的影响。为此，从平移分量中提取了14次地震的扭转分量。通过考虑扭转和平移分量来分析对称和非对称的理想单层模型。这些模型考虑了非耦合扭转频率到脱开的平移频率比的五个不同的值（Ω=  ω _θ / ω _X = 1·5、1·25、1、0·75、0·5），其横向周期从0·05到2 s不等。研究了膜片左侧，右侧和中心的位移，膜片绕质心的旋转以及基础剪力。结果表明，扭转分量对建筑物的非线性响应的影响相当大，而忽略该影响会导致对响应的估计不足。发现由于扭转分量导致的建筑物响应的增加很大程度上取决于Ω值和刚度偏心率。扭转刚度和扭转挠性建筑物位移的最大增长分别为51％和155％。在不对称系统中，膜片旋转可以增加到154％。