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Computers & Structures, Volumes 98–99, May 2012, Pages 7-16
M.F. Huang, C.M. Chan, W.J. Lou
Institute of Structural Engineering, Zhejiang University, Hangzhou 310058, PR China
Department of Civil and Environmental Engineering, Hong Kong University of Science and Technology, Hong Kong
Abstract
Two major wind-induced performance indexes of tallbuildings excited by dynamic and random wind could be the lateral drift and acceleration. The wind-induced performance-baseddesign optimization framework has been developed to take into account uncertainties in the vibration related occupant comfort problems of tallbuildings. An innovative decoupling strategy is adopted to transform the original coupled reliability-based optimization problem into two separated sub problems, which are then solved using the inverse reliability approach and Optimality Criteria (OC) algorithm respectively. A 60-story building example is employed to demonstrate the effectiveness and practicality of the proposed reliability performance-baseddesign optimization method.
Additional Information
considering uncertainties
Modern tall buildings are vulnerable to extreme wind events as they grow increasingly taller and more complex in shape. The global resurgence of supertall structures requires a corresponding innovation in structural design methods. Performance-based approach provides a means to design a building with predictable and acceptable performance under multiple levels of hazards during the lifetime of the building. In the wind performance design framework, performance objectives can be described as the combination of expected performance levels with their corresponding wind hazard intensities, which are measured by the magnitudes of wind speed of a wind hazard.
A four-level wind engineering performance design framework for tall buildings is presented in Figure 1. The basic performance objectives can be considered as the minimum requirements. The motion perception indicates that occupants may perceive the slight motion of a building but not feel discomfort due to the small magnitude of the motion under yearly wind events. Occupant comfort check refers to moderate building motion caused by occasional wind events. The performance objective of immediate occupancy means up to moderate reduction in comfort but no threat to safety or injury during occasional wind events. Life safety related strength check is strictly required for tall buildings under rare wind hazards to ensure structural integrity. Collapse prevention has been taken into account of the potential loss of lateral stability either locally or globally for tall buildings under very rare wind hazard, and arranged as the fourth level of performance objectives. The four levels of basic objectives for wind performance-based design can be summarized as MP (motion perception), IO (immediate occupancy), LS (life safety), and CP (collapse prevention). Enhanced and superior objectives can also be set as shown in Figure 1 for some important building projects.
Two major wind-induced performance indexes of tall buildings excited by dynamic and random wind could be identifed as the lateral drift and acceleration. The wind-induced performance-based design optimization framework has been developed to take into account uncertainties in the vibration related occupant comfort problems of tall buildings. An innovative decoupling strategy is adopted to transform the original coupled reliability-based optimization problem into two separated sub problems, which are then solved using the inverse reliability approach and Optimality Criteria (OC) algorithm respectively. The effectiveness and practicality of the proposed reliability performance-based design optimization methodology have been verified by some significant practical supertall building projects.
