Average spectral acceleration as an intensity measure for collapse risk assessment

2015 ◽  
Vol 44 (12) ◽  
pp. 2057-2073 ◽  
Author(s):  
Laura Eads ◽  
Eduardo Miranda ◽  
Dimitrios G. Lignos
Keyword(s):  
Risk Assessment ◽  
Spectral Acceleration ◽  
Intensity Measure

A spectral-acceleration-based combination-type earthquake intensity measure for high-rise stack-like structures

2019 ◽  
Vol 23 (7) ◽  
pp. 1350-1366 ◽  
Author(s):  
Yikun Qiu ◽  
Changdong Zhou ◽  
Siha A ◽  
Guangwei Zhang
Keyword(s):  
Ground Motion ◽  
Ground Motions ◽  
Spectral Acceleration ◽  
Intensity Measure ◽  
Earthquake Intensity ◽  
Intensity Measures ◽  
Higher Modes ◽  
High Rise ◽  
Near Fault ◽  
Period Elongation

Ground motion intensity measures are of great importance for the seismic design of structures. A well-chosen intensity measure will reduce the detailed ground motion record selection effort for the nonlinear dynamic structural analyses. In this article, a spectral-acceleration-based combination-type earthquake intensity measure is presented. This intensity measure considers the higher modes effect and period elongation effect due to nonlinear deformation at the same time. The modal mass participation factors are determined to take weighting coefficients and the product of elastic first-mode period T1 and a constant C is expressed to represent the elongated period. Therefore, the proposed intensity measure is a combination of earthquake ground motion characteristics, elastic structural responses, higher modes participation, and the period elongation effect due to inelastic structural behaviors. Four three-dimensional models of reinforced concrete stack-like structures including a 240 m-high chimney, a 180 m-high chimney, a 120 m-high chimney, and a 42.3 m-high water tower are established and analyzed in ABAQUS to investigate the correlation between the intensity measure and the maximum curvatures under 44 far-field ground motions and 28 near-fault ground motions with a pulse-like effect. With the optimal vibration modes and the proper period elongation coefficient, the efficiency of the introduced intensity measure is compared with the other 15 intensity measures. The results indicate that the proposed intensity measure is believed to be a good choice for high-rise stack-like structures, especially under the near-fault ground motions with pulse-like effect.

Influence of intensity measure selection on simulation-based regional seismic risk assessment

2020 ◽  
Vol 36 (2) ◽  
pp. 647-672 ◽  
Author(s):  
Ao Du ◽  
Jamie E Padgett ◽  
Abdollah Shafieezadeh
Keyword(s):  
Risk Assessment ◽  
Seismic Risk ◽  
Simulation Method ◽  
Intensity Measure ◽  
Seismic Risk Assessment ◽  
Demand Modeling ◽  
Risk Estimates ◽  
Demand Models ◽  
Simulation Based ◽  
Spatially Distributed

This study investigates the influence of intensity measure (IM) selection on simulation-based regional seismic risk assessment (RSRA) of spatially distributed structural portfolios. First, a co-simulation method for general spectral averaging vector IMs is derived. Then a portfolio-level surrogate demand modeling approach, which incorporates the seismic demand estimation of the non-collapse and collapse states, is proposed. The derived IM co-simulation method enables the first comparative study of different IMs, including the conventional IMs and some more advanced scalar and vector IMs, in the context of RSRA. The influence of IM selection on the predictive performance of the portfolio-level surrogate demand models, as well as on the regional seismic risk estimates, is explored based on a virtual spatially distributed structural portfolio subjected to a scenario earthquake. The results of this study provide pertinent insights in surrogate demand modeling, IM co-simulation and selection, which can facilitate more accurate and reliable regional seismic risk estimates.

Intensity Measure Correlations Observed in the NGA-West2 Database, and Dependence of Correlations on Rupture and Site Parameters

2017 ◽  
Vol 33 (1) ◽  
pp. 145-156 ◽  
Author(s):  
Jack W. Baker ◽  
Brendon A. Bradley
Keyword(s):  
Geometric Mean ◽  
Condition Dependence ◽  
Peak Ground Velocity ◽  
Spectral Acceleration ◽  
Intensity Measure ◽  
Ground Acceleration ◽  
Correlation Models ◽  
Continued Use ◽  
S Peak ◽  
Ground Motion Intensity Measure

This manuscript reports ground motion intensity measure ( IM) correlations for a number of IM types, as measured from the NGA-West2 database. IMs considered are Spectral Accelerations with periods from 0.01 s to 10 s, Peak Ground Acceleration, Peak Ground Velocity, and Significant Duration (for 5–75% and 5–95% definitions). Results are shown for correlations of both maximum-direction and geometric mean spectral acceleration values, given the need for such maximum-direction correlations in a new ASCE 7-16 procedure. Additionally, the potential magnitude-, distance- and site-condition-dependence of IM correlations are evaluated. The results are practically important as IM correlations are increasingly used in a range of engineering and seismic hazard calculations. We find that maximum-direction spectral correlations are comparable to correlations for other spectral acceleration definitions, and that the correlations have no practically significant dependence on magnitude, distance or site conditions. These results support the collective understanding that IM correlations are stable across a range of conditions, and as a result, that existing correlation models are generally appropriate for continued use in engineering calculations.

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