A capacity-demand-spectrum-based method for rapidly estimating inelastic displacement of high-rise buildings under alongwind loads

Abstract

In performance-based wind design (PBWD), the nonlinear time-history analysis (NTHA) method can be used to calculate the structural wind-induced inelastic responses, but this method is complex, inefficient, and time-consuming, making it impractical for the wind design of high-rise buildings. Thus, developing a method that can rapidly estimate the structural inelastic wind effects is an urgent need for PBWD. To address this issue, a capacity-demand-spectrum-based method for rapidly estimating wind-induced inelastic displacement of high-rise buildings is proposed in this study. This method involves the following steps: First, establish the strength reduction factor-ductility factor-natural period (R-μ-T) relationship curve for a single-degree-of-freedom (SDOF) system under alongwind loads, establish the elastic demand spectrum using equivalent static wind loads, and convert the elastic demand spectrum into an inelastic demand spectrum based on the R-μ-T curve. Then, utilizing the pushover method and the characteristics of alongwind response in high-rise buildings, derive and establish the capacity spectrum of high-rise buildings under wind loads. Subsequently, plot the capacity spectrum and inelastic demand spectrum together to find the performance point, and finally restore the inelastic wind-induced displacement from this performance point using the first-mode shape vector or improved shape vectors. A case study is performed to validate the accuracy and efficiency of this proposed method. The study results demonstrate that, compared with the NTHA method, the proposed method significantly improves analysis efficiency while maintaining acceptable accuracy, making it practical for usage in PBWD.