In the design of tall buildings, the most challenging task for structural engineers is to devise an efficient structural system to resist the action of lateral loads. Lateral stiffness design requires a proper selection of an effective structural form and appropriate sizing of all structural elements. Often times in the preliminary design stage of a tall building, several structural alternatives are proposed and the final structural system is generally sought by a time-consuming trial-and-error process....[ Read more ]

In the design of tall buildings, the most challenging task for structural engineers is to devise an efficient structural system to resist the action of lateral loads. Lateral stiffness design requires a proper selection of an effective structural form and appropriate sizing of all structural elements. Often times in the preliminary design stage of a tall building, several structural alternatives are proposed and the final structural system is generally sought by a time-consuming trial-and-error process.

A computer-based method for the preliminary analysis and optimal top drift design of tall building structures is presented in this study. For the purpose of preliminary design, buildings with various structural forms are modelled approximately as two-dimensional shear-flexural beams and analysed by the continuum medium method. In this study, four structural forms including rigid frame structures, shear wall structures, coupled shear wall structures, and outrigger-braced structures are considered.

A rigorously derived Optimality Criteria (OC) technique is developed for the top drift design of tall building structures. Only top deflection is considered because it is the most important starting point for the lateral stiffness design of tall building structures. Using the approximate analytical analysis and the OC design approach, a new computer-based method is developed so that the analysis and the design optimisation of structures can be simultaneously achieved, thus producing a very efficient and powerful design tool to guide design decision at the early design stage. Apart from helping engineers to select proper structural forms, this design tool can be utilized to estimate structural member sizes once a structural form is defined.

A series of tall building examples ranging from rigid frame structures, shear wall structures, coupled shear wall structures, and outrigger-braced structures are presented to illustrate the accuracy and the effectiveness of the preliminary analysis and the design optimisation technique. The results indicate that the responses of tall building structures modelled by the approximate method compare closely with that by the finite element method. The optimal design method is shown to be efficient and thus is a powerful design tool for engineers to establish proper structural forms at the preliminary design stage.