Abstract
Seismic demand on structures may be estimated using linear response spectrum analysis, linear response history analysis, or nonlinear response history analysis. For response history analysis, a set of ground motion record pairs is required. Requirements for nonlinear analysis in current standards typically include development of a set of at least 11 record pairs scaled to a maximum direction target response spectrum. For site-specific ground motion studies, the current standard also specifies a target logarithmic standard deviation of pseudo-spectral acceleration equal to 0.60 across all periods of significance. The purposes of this study include (1) a demonstration that geometric-mean-based scale factors and maximum-direction-based scale factors for design record suites are similar as long as the engineer is aware of the target spectrum basis, (2) an estimation of log-based variability in inelastic displacements for design suites with a target log-based variability in pseudospectral acceleration, and (3) a brief analysis of the directional combination rule typically used in seismic design. To accomplish these goals, a site near Memphis, Tennessee, in the New Madrid seismic zone was selected. The deep soil deposits characterizing the selected site warrant the consideration of site-specific site factors.
Get full access to this article
View all available purchase options and get full access to this article.
Data Availability Statement
Ground motion records used in this study are freely available from the PEER Ground Motion Database. Data generated from the records used in this study are freely available in Microsoft Excel format from the author upon request, as are plain text results files generated from BiSpec (Hachem 2019).
Acknowledgments
The author acknowledges the long-standing contributions of the Pacific Earthquake Engineering Research (PEER) Center, USGS, and the Applied Technology Council (ATC). PEER provides abundant publicly available metadata, processed ground motion records, spectra, and scaling tools for those interested in earthquake engineering and science. The web-based tools from USGS are indispensable in disaggregating seismic hazard, generating hazard curves, and obtaining data for most any mean recurrence interval. Given the variety of requirements from the many different design specifications in use today, these tools bring complicated analyses within reach of practicing engineers and scientists. The ATC Hazards by Location online application permits users to quickly establish not only detailed seismic design criteria in accordance with ASCE 7-16, but also needed wind and snow load data. PEER, USGS, and ATC tools and data were used extensively to perform this study. Finally, the author acknowledges the authors of SigmaSpectra, Albert Kottke and Ellen Rathje, for making such a useful tool freely available.
References
AASHTO. 2011. Guide specifications for LRFD seismic bridge design. 2nd ed. Washington, DC: AASHTO.
ASCE. 2017. Minimum design loads and associated criteria for buildings and other structures. ASCE 7-16. Reston, VA: ASCE.
Boore, D. M. 2010. “Orientation-independent, nongeometric-mean measures of seismic intensity from two horizontal components of motion.” Bull. Seismol. Soc. Am. 100 (4): 1830–1835. https://doi.org/10.1785/0120090400.
Boore, D. M., and T. Kishida. 2017. “Relations between some horizontal-component ground-motion intensity measures used in practice.” Bull. Seismol. Soc. Am. 107 (1): 334–343. https://doi.org/10.1785/0120160250.
Giannopoulos, D., and D. Vamvatsikos. 2018. “Ground motion records for seismic performance assessment: To rotate or not to rotate.” Earthquake Eng. Struct. Dyn. 47 (12): 2410–2425. https://doi.org/10.1002/eqe.3090.
Hachem, M., 2019. “Earthquake solutions.” Accessed March 30, 2019. http://eqsols.com/Bispec.html.
Hashash, Y. M. A., C.-C. Tsai, C. Phillips, and D. Park. 2008. “Soil-column depth-dependent seismic site coefficients and hazard maps for the upper Mississippi embayment.” Bull. Seismol. Soc. Am. 98 (4): 2004–2021. https://doi.org/10.1785/0120060174.
Huff, T. 2015. “Partial isolation as a design alternative for pile bent bridges in the new Madrid seismic zone.” Pract. Period. Struct. Des. Construct. 21 (2): 1–12. https://doi.org/10.1061/(ASCE)SC.1943-5576.0000277.
Kalkan, E., and J. C. Reyes. 2015. “Significance of rotating ground motions on behavior of symmetric- and asymmetric-plan structures: Part II.” Earthquake Spectra 31 (3): 1613–1628. https://doi.org/10.1193/072012EQS242M.
Kottke, A., and E. M. Rathje. 2008. “A semi-automated procedure for selecting and scaling recorded earthquake motions for dynamic analysis.” Earthquake Spectra 24 (4): 911–932. https://doi.org/10.1193/1.2985772.
Ryan, K. L., and A. K. Chopra. 2004. “Estimation of seismic demands on isolators based on nonlinear analysis.” J. Struct. Eng. 130 (3): 392–402. https://doi.org/10.1061/(ASCE)0733-9445(2004)130:3(392).
Stewart, J. P., et al. 2011. “Representation of bidirectional ground motions for design spectra in building codes.” Earthquake Spectra 27 (3): 927–937. https://doi.org/10.1193/1.3608001.
Warn, G. P., and A. S. Whittaker. 2007. Performance estimates for seismically isolated bridges. Buffalo, NY: Multidisciplinary Center for Earthquake Engineering Research.
Watson-Lamprey, J. A., and D. M. Boore. 2007. “Beyond SA-GMRotI: Conversion to SA-Arb, SA-SN, and SA-MaxRot.” Bull. Seismol. Soc. Am. 97 (5): 1511–1524. https://doi.org/10.1785/0120070007.
Information & Authors
Information
Published In
Practice Periodical on Structural Design and Construction
Volume 25 • Issue 1 • February 2020
Copyright
©2019 American Society of Civil Engineers.
History
Received: May 10, 2019
Accepted: Aug 6, 2019
Published online: Sep 30, 2019
Published in print: Feb 1, 2020
Discussion open until: Feb 29, 2020
Authors
Metrics & Citations
Metrics
Citations
Download citation
If you have the appropriate software installed, you can download article citation data to the citation manager of your choice. Simply select your manager software from the list below and click Download.