Torsional coupling effects in the earthquake response of asymmetric buildings

This paper presents a detailed parametric study of the coupled lateral and torsional response of a partially symmetric single storey building model subjected to both steady state and earthquake base loadings. It is shown that the qualitative effects of the controlling parameters on the maximum translational and torsional responses of the coupled system are not affected by the nature of the loading. The maximum lateral edge displacement of the building arising from the combined response effects is investigated. The related lateral shear forces in vertical resisting elements located on the periphery of the structure may be significantly increased in comparison with the corresponding values for a symmetric building. It is concluded that for particular ranges of the key parameters defining the structural system, typical of the properties of many actual buildings, torsional coupling induces a significant amplification of earthquake forces which should be accounted for in their design.