Earthquake analysis of a class of torsionally‐coupled buildings

Abstract An effective procedure is summarized without derivation for estimating the maximum response of a class of torsionally‐coupled, multi‐storey buildings due to earthquake ground motion characterized by response spectra. The analysis procedure is shown to be efficient and to provide insight into torsional coupling effects because the maximum response of such a torsionally‐coupled, N ‐storey building in its nj th mode of vibration is determined exactly by analysing (i) the response in the j th vibration mode ( j = 1,2, N ) of the corresponding torsionally‐uncoupled, N ‐storey system; and (ii) the response in the n th vibration mode ( n = 1, 2 for a one‐way symmetric plan) of an associated torsionally‐coupled, one‐storey system. It is also demonstrated that an earlier, simpler approach in which the total (considering all vibration modes) response of the building is determined from the total response of the two simpler systems is strictly valid only under restrictive conditions, which are identified, but the simpler approach leads to results that are accurate to a useful degree.