STATIC AND DYNAMIC ANALYSIS OF HIGH-RISE BUILDINGS

This thesis is focused on the structural behaviour of high-rise buildings subjected to transversal loads expressed in terms of shears and torsional moments. As horizontal reinforcement, the resistant skeleton of the construction can be composed by different vertical bracings, such as shear walls, braced frames and thin-walled open section profiles, having constant or variable geometrical properties along the height. In this way, most of the traditional structural schemes can be modelled, from moment resisting frames up to outrigger and tubular systems. In particular, an entire chapter is addressed to the case of thin-walled open section shear walls which are defined by a coupled flexural-torsional behaviour, as described by Vlasov’s theory of the sectorial areas. From the analytical point of view, the three-dimensional formulation proposed by Al. Carpinteri and An. Carpinteri (1985) is considered and extended in order to perform dynamic analyses and encompass innovative structural solutions which can twist and taper from the bottom to the top of the building. Such approach is based on the hypothesis of in-plane infinitely rigid floors which assure the connection between the vertical bracings and, consequently, reduce the number of degrees of freedom being only three for each level. By means of it, relevant design information such as the floor displacements, the external load distribution between the structural components, the internal actions, the free vibrations as well as the mode shapes can be quickly obtained. The clearness and the conciseness of the matrix formulation allow to devise a simple computer program which, starting from basic information as the building geometry, the number and type of vertical stiffening, the material properties and the intensity of the external forces, provides essential results for preliminary designs.