Commenced in January 2007
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Seismic Directionality Effects on In-Structure Response Spectra in Seismic Probabilistic Risk Assessment

Authors: S. Jarernprasert, E. Bazan-Zurita, P. C. Rizzo

Abstract:

Currently, seismic probabilistic risk assessments (SPRA) for nuclear facilities use In-Structure Response Spectra (ISRS) in the calculation of fragilities for systems and components. ISRS are calculated via dynamic analyses of the host building subjected to two orthogonal components of horizontal ground motion. Each component is defined as the median motion in any horizontal direction. Structural engineers applied the components along selected X and Y Cartesian axes. The ISRS at different locations in the building are also calculated in the X and Y directions. The choice of the directions of X and Y are not specified by the ground motion model with respect to geographic coordinates, and are rather arbitrarily selected by the structural engineer. Normally, X and Y coincide with the “principal” axes of the building, in the understanding that this practice is generally conservative. For SPRA purposes, however, it is desirable to remove any conservatism in the estimates of median ISRS. This paper examines the effects of the direction of horizontal seismic motion on the ISRS on typical nuclear structure. We also evaluate the variability of ISRS calculated along different horizontal directions. Our results indicate that some central measures of the ISRS provide robust estimates that are practically independent of the selection of the directions of the horizontal Cartesian axes.

Keywords: Seismic, Directionality, In-Structure Response Spectra, Probabilistic Risk Assessment.

Digital Object Identifier (DOI): doi.org/10.5281/zenodo.1337645

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References:


[1] EPRI, 2004, “CEUS Ground Motion Project Final Report: TR 1009684 2004, Electric Power Research Institute, December 2004.
[2] EPRI, 2006, “Program on Technology Innovation: Truncation of the Lognormal Distribution and Value of the Standard Deviation for Ground Motion Models in the Central and Eastern United States,” TR 1014381, Electric Power Research Institute, August 2006.
[3] NRC, 2012, NUREG-2115, “Central and Eastern United States Seismic Source Characterization for Nuclear Facilities,” Nuclear Regulatory Commission, 2012.
[4] NRC, 2006, Regulatory Guide 1.208, "A Performance-Based Approach to Define The Site-Specific Earthquake Ground Motion," Nuclear Regulatory Commission, March 2007.
[5] NRC, 2007, NUREG-0800 "Standard Review Plan Section 3.7.2 - Seismic System Analysis", Nuclear Regulatory Commission, March 2007.
[6] ASCE, 2013, “Seismic Analysis of Safety-Related Nuclear Structures,” Standards ASCE 4-13, American Society of Civil Engineers, 2013.
[7] ASCE, 2005, “Seismic Design Criteria for Structures, Systems and Components in Nuclear Facilities,” ASCE/SEI Standard 43-05, American Society of Civil Engineers, 2005.
[8] CSI, 2007, “Reference Manual for SAP – Version 14,” Computers and Structures, Inc., 2007.
[9] NRC, 2006, Regulatory Guide 1.92, "Combining Modal Responses and Spatial Components in Seismic Response Analysis," Nuclear Regulatory Commission, July 2006.