Evaluation of seismic hazard for the assessment of historical elements at risk: description of input and selection of intensity measures

Abstract

International audienceThe assessment of historical elements at risk from earthquake loading presents a number of differences from the seismic evaluation of modern structures, for design or retrofitting purposes, which is covered by existing building codes, and for the development of fragility curves, procedures for which have been extensively developed in the past decade. This article briefly discusses: the hazard framework for historical assets, including a consideration of the appropriate return period to be used for such elements at risk; the intensity measures that could be used to describe earthquake shaking for the analysis of historical assets; and available approaches for their assessment. We then discuss various unique aspects of historical assets that mean the characterisation of earthquake loading must be different from that for modern structures. For example, historical buildings are often composed of heterogeneous materials (e.g. old masonry) and they are sometimes located where strong local site effects occur due to: steep topography (e.g. hilltops), basin effects or foundations built on the remains of previous structures. Standard seismic hazard assessment undertaken for modern structures and the majority of sites is generally not appropriate. Within the PERPETUATE project performance-based assessments, using nonlinear static and dynamic analyses for the evaluation of structural response of historical assets, were undertaken. The steps outlined in this article are important for input to these assessments

Recent and future developments in earthquake ground motion estimation

“…As stated by Douglas et al (2015), although the characterization of earthquake shaking by a single number (an IM) is a great simplification, it makes seismic hazard assessment much more straightforward since the link between the seismic-source and ground-motion models can be expressed as a closed-form equation [ground motion prediction equations (GMPEs), also known as attenuation relation(ship)s] to estimate the probability of exceeding a given level of earthquake shaking. These probabilities are calculated through probabilistic seismic hazard assessment (PSHA) (Cornell, 1968;McGuire, 1976), which is the basis of most current seismic design maps, e.g.…”

Seismic Performance of Historical Masonry Structures Through Pushover and Nonlinear Dynamic Analyses

“…Other possible IMs are the spectral acceleration for a significant period of vibration of the Fig. 11.1 Principles of PBA through nonlinear static and dynamic analyses asset, the maximum spectral displacement, Arias intensity and Housner intensity (Douglas et al 2015). Advices on the proper selection of IM as a function of various architectural assets (towers, obelisks, single or multi-drum columns, ..) are proposed in Lagomarsino and Cattari (2015).…”

An earthquake-source-based metric for seismic fragility analysis

“…Also, a critical study (Klügel 2007) on the probabilistic seismic-hazard analysis notices the limitations of PSA by energy-conservation principles, noticing that seismic events with very different energy content may have similar PSA. Concerns regarding the performance of the spectral acceleration in estimating demand parameters of realistic structures have been expressed also in Kohrangi et al (2016a, b) and Schotanus et al (2004), which analyse a set of intensity measures used in practice for realistic 3D structures, or in Kostinakis et al (2017) and Douglas et al (2015), which express the need of intensity measures to be structure-specific. A similar observation is offered in Vargas et al (2013), which uses ordinates of the spectral displacement as intensity measure, but seeks an approach that takes into account the non-linear behaviours of structures.…”