صلاح طیف طراحی آئین نامه 2800 ایران برای ساختگاههای نزدیک گسل با استفاده از زلزله های ثبت شده با و بدون اثرات جهت

Document Type : Research Article

Authors

1 Associate Professor, School of Civil Engineering, Iran University of Science and Technology

2 Ph.D. Candidate, School of Civil Engineering, Iran University of Science and Technology

Abstract

Many populated urban areas of Iran are threatened by near source problems; forward directivity effects and fling step, which may cause huge catastrophic. The major reason is that this country is surrounded by the two huge mountain chains, Alborz and Zagross. As an example, Tehran is a city faced around with four near active faults, Mosha, North, Ray, and Karaj faults, which are potentially hazardous. This is under the condition that the design response spectra [A*B(T)] in Iranian Standard No. 2800, which is established on the basis of ten percent chance in fifty years, does not illustratively account for the directivity effects for sites located at near sources. This article is intended to propose a technique to descriptively modify the far field response spectra taking into account such problems for sites 20 Km far away from the active faults. The proposed modification factors are developed based on a limited number of near source data with and without directivity effects (58 recorded data) using three attenuation relationships. The proposed coefficients for four site soil conditions are implemented to the existing far field design response spectra presented in the fourth version of the response spectra. A comparison is made with those of UBC-97 and ASCE-7-2005 corresponding to two seismicity cities in the United State aimed at understanding how to assess their differences. The recommended technique may be interpreted as a start for developing a series of design response spectra having the potentiality of more accurately accounting for the near source problems.

Keywords


[1] Iervolino, Iunio, and C. Allin Cornell, “Probability of occurrence of velocity pulses in near-source ground motions”, Bulletin of the Seismological Society of America 98.5:pp. 2262- 2277, 2008.
[ 2 ]Somerville, Paul G., et al, “Modification of empirical strong ground motion attenuation relations to include the amplitude and duration effects of rupture directivity”, Seismological Research Letters 68.1:pp. 199- 222, 1997.
[ 3 ]Somerville, P., and A. Pitarka, “Differences in earthquake source and ground motion characteristics between surface and buried faulting earthquakes”, Proceedings of the 8th US national conference on earthquake engineering. San Francisco, CA, 2006.
[ 4 ]Bray, Jonathan D., and Adrian Rodriguez-Marek, “Characterization of forward-directivity ground motions in the near-fault region”, Soil Dynamics and Earthquake Engineering 24.11:pp. 815- 828, 2004.
[ 5 ]McKenzie, Dan P, “Speculations on the consequences and causes of plate motions”, Geophysical Journal International 18.1:pp. 1- 32, 1969.
[ 6 ]Kennett, Brian LN, The Seismic Wavefield: Volume 2, Interpretation of Seismograms on Regional and Global Scales. Vol. 2. Cambridge University Press, 2002.
[ 7 ]Nicknam, Ahmad, et al, “Predicting Seismogram at Far Source Site Using Omega- Squared Source Spectrum Model”, Journal of Earthquake Engineering16.1:pp. 105- 124, 2012.
[ 8 ]Beresnev, Igor A., and Gail M. Atkinson, “Modeling finite-fault radiation from the ωn spectrum”, Bulletin of the Seismological Society of America 87.1:pp. 67- 84, 1997.
[ 9 ]Boore, David M, “Simulation of ground motion using the stochastic method”, Pure and applied geophysics 160.3-4:pp. 635- 676, 2003.
[ 10 ]Nicknam, Ahmad, et al, “Extrapolating strong ground motion of the Silakhor earthquake (ML 6.1), Iran, using the empirical Green's function (EGF) approach based on a genetic algorithm”, Canadian Journal of Earth Sciences 46.11:pp. 801- 810, 2009.
[ 11 ]Nicknam, Ahmad, and Yasser Eslamian, “An EGF-based methodology for predicting compatible seismograms in the spectral domain using GA technique”, Geophysical Journal International 185.1:pp. 557- 573, 2011.
[ 12 ]Nicknam, Ahmad, et al, “Synthesizing strong motion using empirical Green's function and genetic algorithm approach”, Journal of Earthquake Engineering14.4:pp. 512- 526, 2010.
[ 13 ]Hutchings, Lawrence, et al, “A physically based strong ground-motion prediction methodology; application to PSHA and the 1999 Mw= 6.0 Athens earthquake”, Geophysical Journal International 168.2:pp. 659- 680, 2007.
[ 14 ]Bouchon, Michel, “A simple method to calculate Green's functions for elastic layered media”, Bulletin of the Seismological Society of America 71.4:pp. 959- 971, 1981.
[ 15 ]Bouchon, Michel, “A review of the discrete wavenumber method”, Pure and applied Geophysics 160.3-4:pp. 445- 465, 2003.
[ 16 ]Hisada, Yoshiaki, and Jacobo Bielak, “A theoretical method for computing near-fault ground motions in layered half-spaces considering static offset due to surface faulting, with a physical interpretation of fling step and rupture directivity”, Bulletin of the Seismological Society of America 93.3:pp. 1154- 1168, 2003.
[ 17 ]Spudich, Paul, and RALPH J. Archuleta, “Techniques for earthquake groundmotion calculation with applications to source parameterization of finite faults”, Seismic strong motion synthetics 37:pp. 205- 265, 1987.
[ 18 ]Prieto, Germán A., et al, “Earthquake source scaling and self‐similarity estimation from stacking P and S spectra”, Journal of Geophysical Research: Solid Earth (1978–2012) 109. B8, 2004.
[ 19 ]Nicknam, Ahmad, and Yasser Eslamian, “A hybrid method for simulating near-source, broadband seismograms: Application to the 2003 Bam earthquake (Mw 6.5)”, Tectonophysics 487.1:pp. 46- 58, 2010.
[20] Nicknam, Ahmad, et al, “Reproducing fling- step and forward directivity at near source site using of multi-objective particle swarm optimization and multi taper”, Earthquake Engineering and Engineering Vibration 12.4:pp. 529- 540, 2013.
[ 21 ]Kalkan, Erol, and Sashi K. Kunnath, “Effects of fling step and forward directivity on seismic response of buildings”, Earthquake Spectra 22.2:pp. 367- 390, 2006.
[ 22 ]Alavi, Babak, and Helmut Krawinkler, “Consideration of near-fault ground motion effects in seismic design”, Proceedings of the 12th World Conference on Earthquake Engineering, 2000.
[ 23 ]NZS1170. 5, “Structural design actions”, part 5: earthquake actions, 2004.
[ 24 ]Spudich, Paul, and Brian SJ Chiou, “Directivity in NGA earthquake ground motions: analysis using isochrone theory”, Earthquake Spectra 24.1:pp. 279- 298, 2008.
[ 25 ]Shahi, Shrey K., and Jack W. Baker, “An empirically calibrated framework for including the effects of near- fault directivity in probabilistic seismic hazard analysis”, Bulletin of the Seismological Society of America 101.2:pp. 742- 755, 2011.
[ 26 ]Boore, David M., and Gail M. Atkinson, “Ground-motion prediction equations for the average horizontal component of PGA, PGV, and 5%- damped PSA at spectral periods between 0.01 s and 10.0 s”, Earthquake Spectra 24.1:pp. 99- 138, 2008.
[ 27 ]Boore, David M., Jennie Watson-Lamprey, and Norman A. Abrahamson, “Orientation-independent measures of ground motion”, Bulletin of the Seismological Society of America 96.4A:pp. 1502- 1511, 2006.
[ 28 ]Boore, David M, “Orientation-independent, nongeometric-mean measures of seismic intensity from two horizontal components of motion”, Bulletin of the Seismological Society of America 100.4:pp. 1830- 1835, 2010.
[ 29 ]Savage, Martha, et al. Seismogenesis and Earthquake Forecasting. Springer, 2010.
[ 30 ]Gupta, I. D, “The state of the art in seismic hazard analysis”, ISET Journal of Earthquake Technology 39.4:pp. 311- 346, 2002.
[ 31 ]Abrahamson, N. A, “Seismic hazard assessment: problems with current practice and future developments”, First european conference on earthquake engineering and seismology, Geneva, Switzerland, 2006.
[ 32 ]Baker, Jack W, “Conditional mean spectrum: Tool for ground-motion selection”, Journal of Structural Engineering 137.3:pp. 322- 331, 2010.
[ 33 ]Luco, N., Ellingwood, B. R., Hamburger, R. O., Hooper, J. D., Kimball, J. K., and Kircher, C. A, “Risk-targeted versus current seismic design maps for the conterminous United States”, Proc. 2007 Structural Engineers Assoc. Calif. (SEAOC) Convention, Lake Tahoe,CA, pp. 163– 175, 2007.
[ 34 ]Stewart, Jonathan P., et al, “Representation of bidirectional ground motions for design spectra in building codes”, Earthquake Spectra 27.3:pp. 927- 937, 2011.
[ 35 ]Somerville, Paul G, “Engineering characterization of near fault ground motions”, Proc., NZSEE, 2005 Conf, 2005.
[ 36 ]Ben-Menahem, Ari, and Sarva Jit Singh. Seismic waves and sources. Courier Dover Publications, 2012.
[ 37 ]Nicknam, Ahmad, et al, “Synthesizing strong motion using empirical Green's function and genetic algorithm approach”, Journal of Earthquake Engineering14.4:pp. 512- 526, 2010.
[ 38 ]Nicknam, Ahmad, et al, “Predicting Seismogram at Far Source Site Using Omega- Squared Source Spectrum Model”, Journal of Earthquake Engineering16.1:pp. 105- 124, 2012.
[ 39 ]Archuleta, Ralph J, “A faulting model for the 1979 Imperial Valley earthquake”, Journal of Geophysical Research: Solid Earth (1978– 2012) 89.B6:pp. 4559- 4585, 1984.
[ 40 ]Kalkan, Erol, and Polat Gulkan, “Site-dependent spectra derived from ground motion records in Turkey” ,Earthquake Spectra 20.4:pp. 1111- 1138, 2004.
[ 41 ]Campbell, Kenneth W., and Yousef Bozorgnia, “NGA ground motion model for the geometric mean horizontal component of PGA, PGV, PGD and 5% damped linear elastic response spectra for periods ranging from 0.01 to 10 s”, Earthquake Spectra 24.1:pp. 139- 171, 2008.
[ 42 ]Abrahamson, Norman, and Walter Silva, “Summary of the Abrahamson & Silva NGA ground-motion relations”, Earthquake Spectra 24.1:pp. 67- 97, 2008.
[ 43 ]Chiou, BrianS-J., and Robert R. Youngs, “An NGA model for the average horizontal component of peak ground motion and response spectra” , Earthquake Spectra 24.1:pp. 173- 215, 2008.
[ 44 ]Regard, V., et al, “Accommodation of Arabia‐Eurasia convergence in the Zagros‐Makran transfer zone, SE Iran: A transition between collision and subduction through a young deforming system”, Tectonics 23.4 , 2004.