Effects of Nonstructural Wall in Progressive Failure of Coastal Residential Buildings Subjected to Strong Winds

Abstract

With many natural hazards impacting coastal communities, the resilience of low-rise residential wood buildings (LRWBs) in the community has been critical. To better understand structural performance under extreme weather conditions, detailed finite-element analysis (FEA) was carried out by many researchers to perform fragility or vulnerability assessment of LRWBs under different types of loadings, such as wind, flooding, or wave or their combinations. In the current codes and specifications, structural and nonstructural components in LRWBs are differentiated from each other when evaluating their functions in terms of safety. Different important factors or different methodologies are proposed and used for the design or usage of structural and nonstructural structural components in LRWBs. In many detailed models for FEA, nonstructural components are usually simplified as mass, and their stiffness is usually ignored in the analysis. However, for existing LRWBs in coastal communities, after years of exposure and continuous operations, significant damage could have accumulated in the structural and nonstructural components or their connections. As a result, the loading path could have shifted differently compared with the original design. It could be very challenging to identify the loading path and differentiate the functions of these structural and nonstructural components in the loading path with changed stiffness contributions as more uncertainties are introduced in the deterioration process for these structural members or connections. The nonstructural systems, such as the interior walls, could possibly affect the loading path in extreme loading conditions. As a result, progressive failure could lead to different failure scenarios if the nonstructural components are not included in the analysis. In the present study, high-fidelity finite-element models for typical LRWBs were built including typical structural and nonstructural components to evaluate the functionality of the nonstructural walls under extreme loading conditions. For comparison purposes, two different finite-element models (FEMs) under different loading scenarios were evaluated and compared. The first model included only structural members, while the second model included both structural and nonstructural members, such as interior walls, which were simulated using shell and beam elements. Different wind loadings were applied on the models to assess the structural resilience. Vulnerability curves were obtained and compared for these two models. Discussions also include the applicable criterion for differentiating structural and nonstructural members in the typical LRWB.