Detection thresholds in structural health monitoring

Trifunac, Mihailo D.; Ebrahimian, Mahdi

doi:10.1016/j.soildyn.2014.07.014

Cited by 10 publications

(6 citation statements)

References 81 publications

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“…In fact, system frequency is always smaller than fixed-based building frequency [27,28]. SSI can play a significant role in the response of structures subjected to earthquakes.…”

Section: Modified Three-dimensional Seismic Assessment Methodsmentioning

confidence: 99%

“…Therefore, a reduction in system frequency that includes both soil and structure is not solely attributed to the stiffness change and damage in the structure. In fact, system frequency is always smaller than fixed-based building frequency [27,28]. The proposed natural frequencies suggested in this study for 3D-SAM are chosen to provide conservative response and damage predictions for buildings as a practical tool for engineers.…”

Section: Modified Three-dimensional Seismic Assessment Methodsmentioning

confidence: 99%

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Modified three‐dimensional seismic assessment method for buildings based on ambient vibration tests: extrapolation to higher shaking levels and measuring the dynamic amplification portion of natural torsion

Mirshafiei

McClure

2016

Earthq Engng Struct Dyn

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Summary This paper presents applications of the modified 3D‐SAM approach, a three‐dimensional seismic assessment methodology for buildings directly based on in situ experimental modal tests to calculate global seismic demands and the dynamic amplification portion of natural torsion. Considering that the building modal properties change from weak to strong motion levels, appropriate modification factors are proposed to extend the application of the method to stronger earthquakes. The proposed approach is consistent with the performance‐based seismic assessment approach, which entails the prediction of seismic displacements and drift ratios that are related to the damage condition and therefore the functionality of the building. The modified 3D‐SAM is especially practical for structures that are expected to experience slight to moderate damage levels and in particular for post‐disaster buildings that are expected to remain functional after an earthquake. In the last section of this paper, 16 low to mid‐rise irregular buildings located in Montreal, Canada, and that have been tested under ambient vibrations are analyzed with the method, and the dynamic amplification portion of natural torsion of the dataset is reported and discussed. The proposed methodology is appropriate for large‐scale assessments of existing buildings and is applicable to any seismic region of the world. Copyright © 2016 John Wiley & Sons, Ltd.

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“…In fact, system frequency is always smaller than fixed-based building frequency [27,28]. SSI can play a significant role in the response of structures subjected to earthquakes.…”

Section: Modified Three-dimensional Seismic Assessment Methodsmentioning

confidence: 99%

Section: Modified Three-dimensional Seismic Assessment Methodsmentioning

confidence: 99%

Modified three‐dimensional seismic assessment method for buildings based on ambient vibration tests: extrapolation to higher shaking levels and measuring the dynamic amplification portion of natural torsion

Mirshafiei

McClure

2016

Earthq Engng Struct Dyn

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“…After 300 s, where the seismic amplitudes are small, starts a partial recovery of the vibration frequencies and it continues for a period of approximately 240 s. This recovery process is also evident in the other moderate-intensity events, but in less time, suggesting that there is a phenomenon that can be related to the SSI effects and soil deformations. This behavior is probably related to the recovery process of the dynamic compaction of the soil under the foundation caused by rocking and horizontal movements at the base of the building during the earthquake (Trifunac and Ebrahimian, 2014; Trifunac et al, 2001).…”

Section: Parametric Analysismentioning

confidence: 99%

Monitoring of a rehabilitated building in soft soil in Mexico and structural response to the September 2017 earthquakes: Part 1: structural health monitoring system

et al. 2021

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The seismic response of an instrumented 22-story rehabilitated building is presented. The building analyzed is as part of a complex (called CCUT) with three low-rise structures and a common basement founded on soft soil that was built in 1964. Since it was under construction until date, the building tower has experienced differential settlements and tilting. To mitigate such problems, the building has been subjected to several rehabilitations over the years. During the 1985 and 2017 high-intensity earthquakes in Mexico City, the tower suffered some damage. The aim of this article is to discuss the structural health monitoring system implemented for the tower and to describe the structure’s performance since the last rehabilitation in 2009. A monitoring methodology designed and implemented as a structural warning system based on five structural health indicators, two on seismic severity and three on structural performance, to automatically process seismic records, is presented. The results of the seismic response of the CCUT tower between 2011 and 2018 indicate that the structure had suffered moderate damage. Analysis of data, corroborated by building inspection, confirmed that the structure exhibited good performance during the 19 September 2017 Puebla-Morelos earthquake. The importance of the information obtained from the structural warning system is highlighted as a promissory tool for establishing a robust decision framework for occupants’ safety.

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“…Understanding and predicting the influence of factors other than damage on damage sensitive parameters is relevant for reducing the threshold of detecting reliably small and localized damage. Such effects are, e.g., the soil‐foundation system, nonlinear elastic structural behavior, and weather 22–32 …”

Section: Introductionmentioning

confidence: 99%

Structural health monitoring of a 32‐storey steel‐frame building using 50 years of seismic monitoring data

Rahmani

Todorovska

2021

Earthq Engng Struct Dyn

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The case study, Los Angeles 32‐storey residential building, has an exceptionally long seismic observation history, spanning 50 years (1971‐2020), during which it has experienced many earthquakes, some causing extensive damage in the metropolitan area. Records of 13 earthquakes are analyzed, including San Fernando of 1971, to find out if permanent loss of stiffness occurred in the structure since 1971 and to describe statistically its nonlinear elastic behavior, not related to damage. It is a rare example of an instrumented pre‐San Fernando earthquake steel‐frame building, constructed with some on‐site welded column‐beam connections, type of construction that exhibited weaknesses after the Northridge, 1994 earthquake. The identification method consists of fitting equivalent uniform and four‐layer Timoshenko beams models by waveform inversion of bandpass filtered impulse responses, which results in piecewise constant profiles of shear wave velocity (the damage sensitive parameter) and the elastic moduli ratio, reflecting the distribution of structural stiffness along the height. The nonlinear elastic behavior derived from the smaller amplitude data constitutes strain‐dependent baseline for future structural health monitoring of this building. This behavior reveals more prominent strain dependency in the longitudinal direction and stronger variation with strain toward the base of the structure.

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Detection thresholds in structural health monitoring

Cited by 10 publications

References 81 publications

Modified three‐dimensional seismic assessment method for buildings based on ambient vibration tests: extrapolation to higher shaking levels and measuring the dynamic amplification portion of natural torsion

Modified three‐dimensional seismic assessment method for buildings based on ambient vibration tests: extrapolation to higher shaking levels and measuring the dynamic amplification portion of natural torsion

Monitoring of a rehabilitated building in soft soil in Mexico and structural response to the September 2017 earthquakes: Part 1: structural health monitoring system

Structural health monitoring of a 32‐storey steel‐frame building using 50 years of seismic monitoring data

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