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Practical Guidelines to Select and Scale Earthquake Records for Nonlinear Response History Analysis of Structures


Printable USGS Open File Report 2010 - 1068, 126 p. (20 Mb)

Erol Kalkan, U.S. Geological Survey, Menlo Park, ekalkan@usgs.gov

Anil K. Chopra, University of California, Berkeley, chopra@ce.berkeley.edu

 

Plain English Summary

Earthquake engineering practice is increasingly using nonlinear response history analysis (RHA) to demonstrate performance of structures. This analysis method requires selection and scaling of ground motions appropriate to design hazard levels. Presented herein is a modal-pushover-based scaling (MPS) method to scale ground motions for use in nonlinear RHA of buildings and bridges. In the MPS method, the ground motions are scaled to match (to a specified tolerance) a target value of the inelastic deformation of the first-”mode” inelastic single-degree-of-freedom (SDF) system whose properties are determined by first-”mode” pushover analysis. Appropriate for first-”mode” dominated structures, this approach is extended for structures with significant contributions of higher modes by considering elastic deformation of second-“mode” SDF system in selecting a subset of the scaled ground motions. Based on results presented for two bridges, covering single- and multi-span “ordinary standard” bridge types, and six buildings, covering low-, mid-, and tall building types in California, the accuracy and efficiency of the MPS procedure are established and its superiority over the ASCE/SEI 7-05 scaling procedure is demonstrated.

Resumen Espanol

Los profesionales de la ingeniería sísmica usan cada vez más análisis cronológico no lineal para verificar el comportamiento de estructuras. Este método de análisis requiere la selección y escalamiento de registros sísmicos apropiados para el nivel de amenaza sísmica de diseño. En este informe se presenta un método basado en pushover-modal (MPS) para escalar los registros sísmicos a usar en el análisis no lineal de edificios y puentes. En el método MPS, los movimientos del terreno se escalan hasta alcanzar un valor objetivo de la deformación del sistema inelástico de un grado de libertad del primer "modo." Las propiedades de este sistema inelástico se determinan conduciendo un análisis de pushover con fuerzas proporcionales al primer modo de vibración. Este procedimiento, inicialmente apropiado para estructuras cuya respuesta esta determinada por el primer modo, se extiende para estructuras con importantes contribuciones de los modos superiores por medio de la consideración de la deformación elástica del segundo modo en el proceso de selección del set final de registros. Con base en resultados para dos puentes ordinarios de una y varias luces y seis edificios de diferentes alturas que cubren las posibilidades de edificios bajos, medios y altos en California, la precisión y la eficiencia del procedimiento MPS queda establecida, así como también su superioridad sobre el procedimiento ASCE/SEI 7-05.

Computer Codes (Matlab and OpenSees)

MPS Example: Skew Bridge (All essential MatLAB and OpenSees codes with clear explanations, 23 Mb)

Related Publications

Kalkan E., Kwong N.S., 2012, Assessment of Modal Pushover-based Scaling Procedure for Nonlinear Response History Analysis of “Ordinary Standard” Bridges, ASCE Journal of Bridge Engineering, 17(2): 272-288

Kalkan E., Chopra A.K., 2010, Practical Guidelines to Select and Scale Earthquake Records for Nonlinear Response History Analysis of Structures, U.S. Geological Survey Open-File Report 2010-1068, 126 p.

Kalkan E. and Chopra A. K., 2011, Modal-Pushover-based Ground Motion Scaling Procedure, ASCE Journal of Structural Engineering, Vol. 137, no. 3, pp. 298-310.

Reyes J.C. and Kalkan E.. 2011, Required Number of Records for ASCE/SEI 7 Ground Motion Scaling Procedure, U.S. Geological Survey Open-File Report 2011 - 1083, 34 p.

Kalkan E., Chopra A. K., 2012, Evaluation of Modal Pushover-based Scaling of one Component of Ground Motion: Tall Buildings, Earthquake Spectra, 28(4): 1469-1493.

 

Comparison of median engineering demand parameters (EDPs) based on theASCE/SEI 7-05 with benchmark EDPs for the 19- and 52-story buildings; individual results for each of the seven scaled ground motions are also presented. The ASCE/SEI procedure grossly overestimates the median values of EDPs due to very small (7) subset of scaled ground motion as compared to the benchmark results. The dispersion of the EDP values due to the 7 scaled records about their median value is unacceptably large indicating that this ground motion scaling procedure is inefficient.

 

Comparison of median engineering demand parameters (EDPs) based on the MPS procedure with benchmark EDPs for the 19- and 52-story buildings; MPS procedure is accurate; the median values of EDPs due to very small (7) subset of scaled ground motion closely match the benchmark results. The dispersion of the EDP values due to the 7 scaled records about their median value is also small indicating that the MPS procedure is efficient.