Scaling wind loads for incremental dynamic analysis applications

Abstract

Incremental Dynamic Analysis is a powerful tool for the performance assessment of structures where a full range of responses can be mapped. Currently, an open discussion among researchers is the scaling of wind loads at increasing hazard intensities. In common practice, local aerodynamic pressure data from wind tunnel testing are normalized with respect to the mean wind velocity. Then, the value is linearly scaled up to provide wind loads at considered limit states. The main issue in the linear scaling of winds is the non-consideration of cross-correlation between different time histories and the mean wind velocity. To address this issue, the Wieringa gust model is applied to account for the dependency of gustiness on mean wind speed, thereby updating the scaling coefficients for both mean and turbulent wind components. This methodology is demonstrated through the application of wind IDA on a high-rise steel hospital in Montreal, Canada. The building is designed to meet the code requirements for wind and earthquake loads. Finite element models that incorporate geometrical and material nonlinearities of building's lateral force-resisting systems are developed in OpenSees. These nonlinear models are used to analyze the impact of linear gust scaling on the building's performance under varying wind intensities.