Multi-hazard performance assessment of low-rise cold-formed steel structures subjected to combined earthquake and wind

Low-rise cold-formed steel (CFS) structures have been used extensively in the low to moderate seismicity zones in many parts of the world. Quite several studies have been conducted focusing on their seismic or wind performance, respectively, neglecting their sensitivity to multi-hazard loading conditions, such as combined strong winds and earthquakes, et al. There is a possibility that strong winds and earthquakes will occur simultaneously based on previous and this paper's studies. However, there is no systematic method for assessing the performance of engineering structures subjected to multi-hazard effects. To fill the above research gaps, this article, drawing upon the research findings of meteorologists and geologists, explicates the mechanisms responsible for the simultaneous occurrence of earthquakes and strong winds. Employing statistical analysis techniques, it explores the probability of concurrent incidents of strong winds and earthquakes through the examination of extensive meteorological and seismic historical data from diverse representative regions. Based on this foundation, establishes a multi-hazard performance assessment method applicable to various structures and hazards and takes two common low-rise CFS structures with and without diagonal struts as the research objects, analyses the dynamic response of both under the combined effects of earthquake and wind loads and completes the performance assessment of CFS structures subject to typical multi-hazard effects. The results are as follows: (1) In various geographical regions, there are instances of strong winds and earthquakes occurring simultaneously. These two distinct forms of disasters exhibit a measurable probability of simultaneous incidence, with this likelihood being notably elevated in particular geographical zones; (2) The multi-hazard performance assessment method proposed herein can effectively take into account the uncertainty of structures and loads, and has good generalizability; (3) For the CFS structures, the effect of earthquake is more significant than that of wind, but with the addition of wind load, the overall dynamic response of the structures is significantly enhanced and the damage probability is significantly increased, and the combined effect of earthquake and wind cannot be ignored; (4) The continuous wind load effect will cause the CFS structures to acquire a greater dynamic response at the end of the earthquake, in other words, a significant increase in the post-earthquake wind effect compared to the pre-earthquake wind; (5) The existence of diagonal struts inside the CFS panels can effectively reduce the dynamic response and damage probability generated by the combined effects of earthquake and wind. The study results can raise researchers' attention to the combined effects of earthquakes and winds and provide a reference for future design methods for multi-hazard resistance of CFS structures.