Quantification of ground-motion parameters and response spectra in the near-fault region

Abstract

This study focuses on the characteristics of near-fault ground motions in the forward-direction and structural response associated with them. These ground motions are narrow-banded in nature and are characterized by a predominant period at which structures excited by them are severely affected. In this work, predominant period is defined as the undamped natural period of a single-degree-of-freedom (SDOF) oscillator at which its 5% damped linear elastic pseudo-spectral velocity (PSV) contains a clear and dominant peak. It is found that a linear relationship exists between predominant period and seismic moment. An empirical equation describing this relationship is presented by using a large set of accelerograms. Attenuation equations are developed to estimate peak ground velocity (PGV) as a function of earthquake magnitude and source-to-site distance. In addition, a predictive equation for spectral shapes of PSV (i.e., PSV normalized by PGV) is presented as a continuous function of the undamped natural period of SDOF oscillators. The model is independent of PGV, and can be used in conjunction with any available PGV attenuation relation applicable to near-fault ground motion exhibiting forward-directivity effects. Furthermore, viscous damping of the SDOF is included in the model as a continuous parameter, eliminating the use of so-called damping correction factors. Finally, simple equations relating force reduction factors and displacement ductility of elasto-plastic SDOF systems are presented.

Seismic Reliability Assessment of Rocking Behaviour Under Near-Fault Excitations

“…Alternatively, the velocity pulse expression of Equation (2) can be utilized with the scaling laws of T p and V p proposed by Mavroeidis and Papageorgiou [19] and Halldorsson et al [22], respectively. Note that the predominant periods estimated by [19] and [20] are not necessarily the same. In addition, the peak ground velocity (PGV) obtained from [20] has not the same value with the V p estimated by [22].…”

“…Note that the predominant periods estimated by [19] and [20] are not necessarily the same. In addition, the peak ground velocity (PGV) obtained from [20] has not the same value with the V p estimated by [22].…”

“…For every earthquake moment magnitude M w and epicentral distance from the fault R e , the mean value of the velocity amplitude V p in centimeters/second and the corresponding mean value of the period T p in s are obtained from [20]: 2 2 log( ) 5.17 1.98 0.14 0.10 log( 0.562)…”

Sensitivity Analysis of the Seismic Response of Brittle Structural Elements Under Near-Field Seismic Input Effects

“…In general, any distance less than 50 or 65 kilometres should be considered near for exposure to a major earthquake [6]. Near-fault ground motions are narrow-banded in nature and are characterized by a predominant period, and structures excited by them are severely affected [7]. Under those conditions, the motion may strongly depend on the complex coupling of the seismic source, rupture process, source-site travel path and local site conditions [8,9].…”

Recent advances in engineering characteristics of near-fault ground motions and seismic effects of building structures

“…Generally speaking, near-fault ground motions are referred to the earthquake ground motions which are close to the rupture surface with the fault distance smaller than 20 km, and strongly depend on the rupture mechanism and obviously involve rupture forward directivity and fling-step effect. At present, there are numerous of theoretical and experimental studies on the analysis of seismic responses and dynamic performance in building and bridge engineering, including the base-isolated structures and energy dissipation structures subjected to near-fault ground motions (Alavi and Krawinkler 2004;Kalkan and Kunnath 2006;Yi and Zhang 2007;Tang et al 2007;Zhao et al 2008;Rupakhety and Sigurdsson 2011;Zamora and Riddell 2011;Ma et al 2012;Li et al 2012;Psycharis et al 2013).…”