A framework for life-cycle cost optimization of buildings under seismic and wind hazards
Date
2014
Authors
Cheng, Guo, author
Mahmoud, Hussam, advisor
Atadero, Rebecca, committee member
Strong, Kelly, committee member
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Abstract
The consequential life and economic impact resulting from the exposure of building structures to single hazards have been well quantified for seismic and wind loading. While it has been recognized that structures are likely to be subjected to multiple hazards during their service life, designing for such scenario has been achieved by as considering the predominant hazard. Although from a structural reliability perspective, this might be a reasonable approach, it does not necessarily result in the most optimal life-cycle cost for the designed structure. Although such observation has been highlighted in recent studies, research is still needed for developing an approach for multi-hazard life-cycle optimization of structures. This study presents a framework, utilizing structural reliability, for cost optimization of structures under wind and seismic hazards. Two example structures, on which the framework is applied, are investigated and their life-cycle cost analyzed. The structures represent typical medium and high rise residential buildings located in downtown San Francisco area. The framework comprises of using the first order reliability method (FORM), programed in MATLAB and interfaced with ABAQUS finite element software to obtain the corresponding reliability factors for the buildings under various loading intensities characterized by the probability of exceedance. The finite element analyses are carried out based on real seismic and wind pressure records using nonlinear finite element time-history dynamic analysis. The random variables selected include hazard intensity (wind load and seismic intensity) and elastic modulus of steel. Once the failure probabilities are determined for the given limit state functions, the expected failure cost for the building service duration considering earthquake or wind hazard, or both, is calculated considering discount rate. The expected life-cycle cost is evaluated using life-cycle cost function, which includes the initial construction cost and the expected failure cost. The results show that the optimal building design considering the wind hazard alone, the seismic hazard alone or a combination of both is different. The framework can be utilized for an optimal design of both wind and seismic load for a given level of hazard intensity.
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Subject
finite element
reliability
multiple hazard