Probabilistic Scenario Approach to Structural Design

摘要

Sustainability of infrastructure depends on the ability of designers to foresee future interactionsrnbetween the building and its environment. Whereas representing these interactions as dead and livernloads leads to satisfactory designs, additional consideration of specific events in the probabilisticrnspace and application of advanced simulation techniques exhibits the potential to facilitate betterrnand more sustainable design. To illustrate the event based analysis, scenario of localized failure duernto malicious human activity is presented in this paper. Probability of building occupant survival isrnintroduced as a measure to compare effectiveness of alternative designs. Since there are numerousrnpossibilities of local failures, number of feasible scenarios were selected and analyzed using thernMonte Carlo sampling. For localized failure, interaction between the building and its environmentrnwas characterized as a sudden removal of a key structural member. Such analysis is at the forefrontrnof civil engineering modeling because it involves material nonlinearities, large deflections, finiternstrains, and certainly requires dynamic analysis. The modeling aspects (e.g. retrieving reliablernstructural information, probabilistic geometric inaccuracies, and material model) are presented. Forrneach scenario, conditional probability of survival was calculated. Consecutively the theorem of totalrnprobability was used to evaluate the global probability of occupant survival for the considered arrayrnof events. Calculated scalar measure provides an opportunity to employ optimization algorithms tornproduce the safest structural design and save human lives in the case of abnormal loadings and/orrnunexpected hazards. In the proposed scenario based analysis, not only structural integrity afterrncompletion of construction is achieved, but also other specific objectives (e.g. high survivability inrnthe case of abnormal loading). Presented methodology can be extrapolated to analyze fire resistance,rnflooding, truck impact, etc., in order to achieve desirable building characteristics and sustainablerninfrastructure.