Residual displacement estimation for soft soils: Application to Mexico city lake-bed

Self Cite

The simplicity, timeliness, and reliability of a post-earthquake assessment are fundamental for decision-makers in emergency management. An adequate risk assessment will help during the recovery and, therefore, increases the resilience of the community. Although within this context, the walk-down damage survey with the correct filling of evaluation forms and use of processing-data tools make possible a pertinent post-earthquake assessment, it is desirable to have measurable parameters that can complement the visual field evaluation with quantitative information. In some cases, basic quantitative measures, such as crack width, are not enough to make pertinent structural damage assessments. This article presents a fast and simple methodology to estimate the median maximum displacement and plastic energy demands on simple single-degree-of-freedom systems from the residual displacement they exhibit after being subjected to ground motions generated in the lakebed zone of Mexico City. Based on this, a discussion is offered on how a post-earthquake assessment can be improved by complementing the visual and measured information gathered on an existing structural system after an intense ground motion, with estimates of its maximum and cumulative plastic deformation demands derived from its residual deformation.

Section: Analytical Validation Of the Proposed Methodologymentioning

confidence: 92%

Section: Relationship Between Maximum and Residual Displacementsmentioning

confidence: 99%

Section: Relationship Between Maximum and Residual Displacementsmentioning

confidence: 99%

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

Quinde¹,

Terán‐Gilmore²,

Reinoso³

2021

Self Cite

“…Accelerometric stations of Mexico City (triangles) and the map of soil predominant periods (T) of the basin (adapted from Quinde et al, 2020). …”

Section: Accelerometric Stations and Soil Periodsmentioning

confidence: 99%

Long duration and frequent, intense earthquakes: Lessons learned from the 19 September 2017 earthquake for Mexico City’s resilience

Quinde¹,

Reinoso²

2020

Self Cite

The accumulation of plastic deformations during an intense earthquake may cause structural failures at deformations significantly smaller than those that can be developed under monotonic load. However, there is evidence that, under certain circumstances, the response of a single parameter may not be a good indicator of structural damage. Likewise, most of the seismic regulations, including the Mexican standards, establish their criteria considering the occurrence of strong earthquakes with a very little probability of occurrence, but do not consider if intense earthquake affects the building frequently and, therefore, cumulative damage due to the occurrence of several earthquakes during the life span of the structure is not taken into account explicitly. This cumulative damage is especially important in places like Mexico City, where intense and long-duration earthquakes occur every 10–20 years. To study the issues that Mexico City must face to increase its seismic resilience, in this article, we present an analysis of the dissipated plastic energy demands in Mexico City during the earthquake of 19 September 2017, and the cumulative damage due to recent intense earthquakes that affect the city.

“…Particularly, residual displacement ratios significantly decrease when the natural period is close, or equal, to the predominant period of the ground motion recorded in soft-soil site. Very recently, Quinde et al (2020) developed a simplified relation between the residual and peak inelastic displacement demands for soft soils. For estimation of the residual displacements of structures under the mainshock-aftershock sequences, an average residual displacement spectrum was proposed by Amiri and Bojo´rquez (2019), where the residual displacements were normalized with respect to the elastic spectral ones.…”

Section: Introductionmentioning

confidence: 99%

Study on normalization of residual displacements for single-degree-of-freedom systems

Feng

Gong

2021

Residual displacement spectrum is one of the most important means to predict the permanent deformation of structures after the earthquake, and various normalizations of residual displacements have generally been used for construction of the spectrum. However, the issue regarding the merits and drawbacks of each normalization has not yet been investigated thoroughly. A comparison between two normalizations that relate the residual displacements to the elastic and inelastic displacements is made in terms of the effect of ground motion and structural characteristics by means of the results of nonlinear time history analysis. The statistical results reveal that the residual-to-peak-inelastic displacement ratios have the advantages of small dispersion, samples without any outliers, and relatively symmetric distribution, which benefits from the strong correlation between residual and peak inelastic displacements. Moreover, the residual-to-peak-inelastic displacement ratios are almost independent of site conditions, significant duration, and natural periods. Consequently, the peak inelastic displacements are superior to the elastic ones as an intermediate step for residual displacements estimation, provided that the peak inelastic displacements are estimated with a low uncertainty. For providing alternatives to estimate residual displacement demands, the constant-strength residual displacement spectra are developed for both normalizations.