Correlations between Energy and Displacement Demands for Performance-Based Seismic Engineering

Abstract

Artículo de publicación ISIThe development of a scientific framework for performance-based seismic engineering requires, among other steps, the evaluation of ground motion intensity measures at a site and the characterization of their relationship with suitable engineering demand parameters (EDPs) which describe the performance of a structure. In order to be able to predict the damage resulting from earthquake ground motions in a structural system, it is first necessary to properly identify ground motion parameters that are well correlated with structural response and, in turn, with damage. Since structural damage during an earthquake ground motion may be due to excessive deformation or to cumulative cyclic damage, reliable methods for estimating displacement demands on structures are needed. Even though the seismic performance is directly related to the global and local deformations of the structure, energy-based methodologies appear more helpful in concept, as they permit a rational assessment of the energy absorption and dissipation mechanisms that can be effectively accomplished to balance the energy imparted to the structure. Moreover, energy-based parameters are directly related to cycles of response of the structure and, therefore, they can implicitly capture the effect of ground motion duration, which is ignored by conventional spectral parameters. Therefore, the identification of reliable relationships between energy and displacement demands represents a fundamental issue in both the development of more reliable seismic code provisions and the evaluation of seismic vulnerability aimed at the upgrading of existing hazardous facilities. As these two aspects could become consistently integrated within a performance-based seismic design methodology, understanding how input and dissipated energy are correlated with displacement demands emerges as a decisive prerequisite. The aim of the present study is the establishment of functional relationships between input and dissipated energy (that can be considered as parameters representative of the amplitude, frequency content and duration of earthquake ground motions) and displacement-based response measures that are well correlated to structural and non-structural damage. For the purpose of quantifying the EDPs to be related to the energy measures, for comprehensive range of ground motion and structural characteristics, both simplified and more accurate numerical models will be used in this study for the estimation of local and global displacement and energy demands. Parametric linear and nonlinear time-history analyses will be performed on elastic and inelastic SDOF and MDOF systems, in order to assume information on the seismic response of a wide range of current structures. Hysteretic models typical of frame force/displacement behavior will be assumed for the local inelastic cyclic response of the systems. A wide range of vibration periods will be taken into account so as to define displacement, interstory drift and energy spectra for MDOF systems. Various scal...

Preliminary ranking of alternative scalar and vector intensity measures of ground shaking

“…The objective of these proposals is not only to improve the predictive efficiency of the IM for all damage levels of a given structure, but also to account for the IM computability through a ground-motion hazard analysis without the need of any new attenuation relationships. Moreover, numerous spectrum-based scalar IMs including energyderived ones were investigated, and studies showed that velocity-based IMs are in general better correlated to deformation demands especially in the case of medium rise frame structures (Akkar and Ö zen 2005;Riddell 2007;Yakut and Yilmaz 2008;Jayaram et al 2010;Mollaioli et al 2011). In Jayaram et al (2010) and Mollaioli et al (2011), the effect of near-fault ground motions and different soil types was also taken into account in evaluating predictive capabilities of the prescribed IMs.…”

An energy‐frequency parameter for earthquake ground motion intensity measure

“…Energy parameters, as cumulative measures, have been demonstrated to be strongly related to EDPs in seismic hazard analysis because it considers the amplitude, frequency, and duration of ground motion. 26,27 For example, structure-specific energy parameters, such as absolute input energy, 28 the total dissipated energy, 29 and referential energy, 30 are confirmed as useful indices in predicting the structural behavior. 31 The non-structure-specific energy parameters related to ground motion amplitude (such as 𝐼 𝑎 , CAV, and 𝑎 𝑟𝑚𝑠 ) and response spectrum (such as ASI and SI ) are also widely used as IMs in seismic hazard and risk analysis.…”

Post-earthquake fast damage assessment using residual displacement and seismic energy: Application to Mexico City

“…Although traditional methodologies for earthquake-resistant design do not consider cumulative plastic deformation demands, there is strong evidence that, under certain circumstances, the maximum displacement response may not be a good indicator of structural damage. In the presence of large cumulative plastic deformation demands, long-duration ground motions can lead to failure of structural elements at deformation levels that are significantly lower than those established for monotonic loading (Arroyo and Ordaz, 2007; Bojórquez et al, 2009; Cheng et al, 2015; Cosenza and Manfredi, 1996; Fajfar, 1992; Kalkan and Kunnath, 2008; Kunnath and Chai, 2004; Leelataviwat et al, 2009; Mollaioli et al, 2011; Teran-Gilmore and Jirsa, 2005; Trifunac, 2008). This type of failure, usually addressed as low-cycle fatigue, requires a careful assessment of the dissipated plastic energy.…”