Wind Load Model And Wind-induced Response Of Tapered Super-tall Building

Wind load is a controlling load for super-tall building’s designing. Aerodynamic treatment is the most effective measure to improve super-tall building’s wind-resist performance. So aerodynamic treatments have been paid more and more attention. Tapering is a kind of shape of super-tall building which’s cross section decreases along the height. Tapering is not only an effective aerodynamic treatment, but also an expressive sharp that favored by architects. Tapering can reduce wind load, but, at the same time, storey stiffness is also reduced. And it is not known that whether wind-induced response is reduced or not. This is a question that worth to focus. Based on these background, the following works have been carried out.(1) High frequency pressure integration (HFPI) wind tunnel tests were made on4tapered models. And wind load characteristics of tapered super-tall building were studied. It can be drawn that:tapering can reduce power spectra of along-wind and across-wind wind force. Also tapering can reduce the peak of power spectra of across-wind wind force. Tapering can magnify the frequency of major vortex shedding.(2) From practical view, and taking China Load coad into consideration, this article proposed mathematic model of wind load on tapered super-tall building. Based on "Load code for the design of building structures, GB50009-2012", through across-wind base moment power spectra’s tapering rate impact factor, this article proposed mathematic model of power spectra of across-wind base moment. Based on "Specification for steel structure design of tall buildings, DG/TJ08-32-2008", through RMS of across-wind base moment’s tapering rate impact factor, this article proposed mathematic model of RMS of across-wind base moment. Through height and tapering rate impact factor of across-wind storey force power spectra, this article proposed mathematic model of power spectra of storey across-wind force.(3)Based on finite element method, this article analyzes static and dynamic properties of tapered super-tall building. Then this article analyzes wind-induced response and equivalent static wind load (ESWL) of tapered super-tall building. The results are as follows. Tapering can reduce response of displacement of along-wind direction. Tapering can increase top part of the building’s displacement response of across-wind direction and tapering can reduce bottom and middle part of the building’s displacement response of across-wind direction. Tapering can increase response of acceleration of along-wind and across-wind direction. Tapering can reduce equivalent static wind load of along-wind direction.