Effects of City Growth on Tall Building Cladding Fatigue
Abstract
As city develops there will be changes in the aerodynamic characteristics due to varying building surrounding and topology. For example, the city growth around a tall building can cause an increase in wind load due to venturi or wake effects or decrease due to sheltering effects depending on the type of surrounding. The densification of cities will also increase the turbulence level due to wake effects. In the present study, the implication of these changes on the aerodynamic forces on cladding connections is investigated. With increased fluctuations in the wind loads, the cladding connections will also experience stress fluctuations, which may result in fatigue problems in its lifetime. The growth of an urban area is represented by placing surrounding buildings with different height around the study building, and testing them in a boundary layer wind tunnel. Five surrounding conditions were investigated including isolated, surrounded with 1/4 H,1/2 H, 3/4 H, and H, where H is the height of the study building. The wind tunnel measured cladding pressure was then used to estimate the stress in the connections. Additional CFD simulations were carried out to explain aerodynamic mechanisms and results. Finally, fatigue damages were evaluated for different city development stages using two methods (i) direct wind time history method developed as part of this study and (ii) Weibull wind distribution methods adopted from literature. The highest fatigue loads are found to occur in the following order 1/4H,1/2 H, 3/4 H, and H.