You are hereProbabilistic Seismic Demand Analysis Using Advanced Ground Motion Intensity Measures, Attenuation Relationships, and Near-Fault Effects

Probabilistic Seismic Demand Analysis Using Advanced Ground Motion Intensity Measures, Attenuation Relationships, and Near-Fault Effects

Polsok Tothong
Principal Advisor: 
C. Allin Cornell
Year Published: 
Mon, 01/01/2007 (All day)
Tothong_Polsak.pdf3.33 MB


In performance-based earthquake engineering (PBEE), evaluating the seismic performance (or seismic risk) of a structure at a designated site has gained major attention, especially in the past decade. One of the objectives in PBEE is to quantify the seismic reliability of a structure (due to future random earthquakes) at a site. For that purpose, Probabilistic Seismic Demand Analysis (PSDA) is utilized as a tool to estimate the mean annual frequency of exceeding a specified value of a structural demand parameter (e.g., interstory drift ratio). This dissertation focuses on applying advanced scalar ground motion intensity measures ( IM s, specifically, inelastic spectral displacement ( di ) and di , with a higher-mode factor, denoted as IM II&2E ) when assessing the seismic performance of structures. The results using these advancedIM s are compared with a conventional elastic -based scalar IM (i.e., pseudo spectral acceleration, ) and the vector IM (i.e., with epsilon, denoted as < , [varepsilon]>). The advantages of applying advanced IM s are: (i) "sufficiency" or more accurate evaluations of seismic performance can be achieved while eliminating the need to perform detailed ground motion record selection for the nonlinear dynamic structural analyses, (ii) "efficiency" or smaller variability of structural responses, and (iii) "scaling robustness," which implies that ground motion records can be scaled without introducing a bias in the structural responses. For ordinary records, using the advanced IM s ( di and IM II&2E ) leads to the same conclusions obtained using the vector IM , < , [varepsilon]>. However, using advanced IM s to evaluate the structural performance for near-source pulse-like records is found to be more accurate than using the elastic-based IM s (i.e., and < , [varepsilon]>).


For structural demands that are dominated by the first mode of vibration, using di can be advantageous relative to the conventionally-used and < , [varepsilon]>. We demonstrate that this is true for ordinary and for near-source pulse-like earthquake records; the latter cannot be adequately characterized by either alone or < , [varepsilon]>. For structural demands with significant higher-mode contributions (under either of the two types of ground motions), an advanced scalar IM that incorporates higher modes needs to be utilized.