| This thesis describes aspects of both uncoupled and coupled vibrations of symmetric and asymmetric structures in uniform tall buildings. A systematic. study is presented for analysis of uncoupled vibrations, which include shear vibration of frames, flexural vibration of walls, flexural-shear vibration of wall-frames, lateral vibration of coupled walls, and torsional vibrations (St Venant, warping and Vlasov torsional vibrations) of symmetric structures. The analysis is based on the continuous medium approach, in which a tall building structure may be replaced by an idealised cantilever continuum representing the structural characteristics.; The study of the thesis is then extended from the uncoupled vibrations to cover and emphasise on both doubly-coupled and triply-coupled vibrations of asymmetric structures in tall buildings. The structures include not only different forms of lateral-loading and torque resisting bents, such as frames, shear walls, wall-frames, structural cores and coupled walls, but also any combinations of these structures, referred herein as the “general complex structures”.; Using the analytical method based on the theory of differential equations, a general solution to the eigenvalue problem of general complex structures in triply-coupled vibrations is derived. The method is less approximate and, from theoretical research's point of view, may enlarge the content of coupled vibration in the theory of the structural vibration. Moreover, a generalised approximated technique, by applying the Galerkin method, for conducting the dynamic analysis of tall building structures is proposed for determining the natural frequencies and the corresponding mode shapes of tall building structures in coupled vibrations.; Coupled vibration analyses of a series of example tall buildings with different structural forms has been conducted by the proposed approximate method to demonstrate its practical applications and to validate its simplicity and accuracy. The proposed method for predicting the natural frequencies and the corresponding mode shapes of coupled vibration is shown to give very good agreement with those of FEM analysis; thus the proposed technique offers a simple and efficient, yet accurate, means of coupled vibration analysis of asymmetric structures in tall buildings.; A procedure of computation, based on the proposed method, is presented in detail to show how the analysis of coupled vibration is carried out and the natural frequencies and corresponding mode shapes of coupled vibration are determined. It is shown that the method of analysis and the computational procedure are efficient and reliable to use for the preliminary design of tall buildings, and also for carrying out quick checks on existing building structures and on the analyses by employing other complicated methods.; A parametric study is finally presented. It permits us to visualise conveniently the dynamic performance of tall building structures in detail, and hence to understand qualitatively how the coupled frequencies and the corresponding mode shapes are related to the key parameters of a given structure. Accordingly, a series of design charts is constructed, which allows designers to estimate quickly the coupled vibration of tan buildings at the preliminary design stage. |
