Optimal Design of Outrigger Systems for Super Tall Buildings

Applied widely to increase the lateral stiffness of supper tall buildings, outriggers can effectively reduce vibration period as well as the structural lateral deflection under wind loads and earthquake actions. Based on the feature of mega frame-core wall structures, this paper discussed the optimal design of outrigger trusses. The location and number of outriggers are optimized by adopting sensitivity vectors algorithm (SVA) method proposed by the authors. Using the principle of virtual work and Rayleigh method, the relationships between the structural member sectional dimensions and the design criteria, such as the story drift and vibration period, are established. Then a Matlab- based computer programe is developed on the basis of SQP approach to minimize the volume of outrigger truss members under multiple constraints. A 729-meter real super tall building project is employed to illustrate the applicability and effectiveness of the proposed optimal design method.