Assembly-Based Vulnerability of Buildings and Its Uses in Seismic Performance Evaluation and Risk Management Decision-Making

A methodology is presented to evaluate the seismic vulnerability of buildings on a building-specific basis. The methodology, entitled assembly-based vulnerability, estimates repair cost, repair duration, and loss-of-use cost as functions of spectral acceleration. It treats the building as a unique collection of standard assemblies with probabilistic fragility, repair costs, and repair durations. The procedure applies Monte Carlo methods to simulate ground motion, structural response, assembly damage, repair costs, and repair duration. The methodology is illustrated using a realistic example office building.

The dissertation also presents a decision-analysis approach to making seismic risk-management decisions for individual buildings, using the assembly-based vulnerability methodology. The decision analysis accounts for the decision-maker’s business practices and risk attitude, and produces a recommendation of the best alternative on an expected-utility basis. A detailed procedure for eliciting the decisionmaker’s risk attitude is presented. The methodology is illustrated using a realistic example decision situation. It is found that risk attitude can make a material difference in the selection of the optimal risk-management alternative, thus calling into question techniques that assume risk neutrality and rely on cost-effectiveness as the key measure of desirability.

Various techniques are presented for developing empirical and theoretical assembly fragilities; these techniques are illustrated through the creation of fragility functions for a wide variety of structural, nonstructural, and content assemblies. The fragility functions can be reused in subsequent analyses. Fragilities are defined within the framework of a standardized, detailed, and highly adaptable assembly taxonomy that can facilitate unambiguous communication of assembly types, fragilities, and costs.