A non-linear static approach for the prediction of earthquake-induced deformation of geotechnical systems
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A non‑linear static approach for the prediction of earthquake‑induced deformation of geotechnical systems R. Laguardia1 · D. Gallese1 · R. Gigliotti1 · L. Callisto1 Received: 30 March 2020 / Accepted: 30 August 2020 © The Author(s) 2020
Abstract This paper illustrates an original and simple method to predict earthquake-induced deformations of geotechnical systems. The method is an extension of static non-linear analysis, and is conceived to predict the behaviour of geotechnical systems, like supported and unsupported excavations, that during the seismic motion accumulate displacements in a single direction. The seismic capacity of the system is described by its capacity curve, obtained either from a numerical push-over analysis or through a simplified procedure. The corresponding seismic demand is described by a combination of the elastic response spectrum, including basic information on the maximum amplitudes of the seismic motion, and a cyclic demand spectrum, that provides additional information about the equivalent number of cycles that contribute to the accumulation of displacements. In the paper, the method is described in detail and is validated through different procedures, namely: comparisons with experimental results obtained in the geotechnical centrifuge; comparison with results of advanced numerical analyses; extensive comparison, using a large database of seismic records, with the results of non-linear time-domain analyses. In its final part, the paper provides guidance for the practical use of the method for design. Keywords Seismic design · Retaining structures · Earthquake-induced displacements · Cyclic demand · Ground motions
1 Introduction When subjected to seismic actions, many geotechnical systems are characterised by a strongly asymmetric behaviour. Some examples are provided in Fig. 1: slopes, unsupported excavations, and different types of retaining structures are all subjected to gravity forces that tend to displace the soil and the structural members towards the weaker zone of the system (namely, to the left in Fig. 1). Because of this asymmetry, during a severe earthquake these systems tend to accumulate irreversible deformations, mostly deriving from the transient activation of their global resistance. It is for this reason that * R. Laguardia [email protected] 1
Department of Structural and Geotechnical Engineering, Sapienza University of Rome, via Eudossiana 18, 00184 Rome, Italy
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Vol.:(0123456789)
Bulletin of Earthquake Engineering
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Fig. 1 Examples of displacing retaining systems: a unsupported excavation; b embedded retaining structure; c gravity retaining structure
the seismic performance of these geotechnical systems is often assessed on the basis of their final deformation (e.g. Richards and Elms 1979). In the past, it has been proposed to compute the final displacements of these systems through a sliding-block analysis. This was originally suggested by Newmark (1965) for the seismic analysis of earth dams and was subsequently ext
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