Advancements to Performance-Based Earthquake Engineering Methods: from Building Code Provisions to Regional Loss Assessment

DeBock, David Jared

Graduate Thesis Or Dissertation

Advancements to Performance-Based Earthquake Engineering Methods: from Building Code Provisions to Regional Loss Assessment Público Deposited

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Citeable URL: https://scholar.colorado.edu/concern/graduate_thesis_or_dissertations/1c18df96k

Abstract

The essence of performance-based earthquake engineering (PBEE) is to design and assess structures to meet specific performance goals, rather than prescriptive requirements. This thesis applies PBEE methods to three problems: (1) evaluating the effectiveness of accidental torsion requirements for seismic design; (2) quantifying spatial correlations of building responses for regional seismic loss assessments; (3) developing and evaluating regional seismic loss assessment methodologies.(1) Seismic ground motions induce torsional responses in buildings that are difficult to predict. To compensate for this, most modern building codes require the consideration of accidental torsion when computing design earthquake forces. This study evaluates the influence of accidental torsion seismic design requirements on the performance of 230 archetypical buildings, taking collapse capacity as the performance metric. The study concludes that accidental torsion provisions may not be necessary for seismic design of buildings without excessive torsional flexibility or asymmetry.(2) The possible seismic losses to a portfolio of buildings are of interest for insurance and reinsurance companies, developers, and policy makers. Probabilistic estimates of earthquake- induced losses to portfolios of buildings require quantifying correlations between losses of the different buildings comprising the building stock. This study examines spatial correlations in building seismic responses. The results demonstrate that correlation patterns in building response parameters are closely linked to correlations in spectral acceleration measured at buildings' first- mode periods. Based on this finding, enhancements are proposed to state-of-the-art methods for regional loss assessment to account for correlations in building response. These building responses provide the basis for computation of earthquake-induced losses in the regional building stock.(3) This study compares current and developing probabilistic regional (portfolio) loss assessment methods, including those proposed in (2). Of particular interest are: the impact of directly computing losses from building response measures rather than ground motion intensity measures; identifying best practices for predicting collapsed buildings; and examining the sensitivity of loss assessments to other methodological decisions related to building stock classification, exposure, and key sources of uncertainty. On the basis of the identified strengths and weaknesses of the different regional loss assessment techniques, "high-end" and "simplified" methods are recommended for computing probabilistic regional seismic losses.

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