Pub Date : 2023-09-23DOI: 10.1177/87552930231199059
Karim Tarbali, Brendon A Bradley, Jack W Baker
This article investigates the correlation coefficients of ground-motion intensity measures for ground motions containing near-fault directivity velocity pulses. These correlation coefficients are necessary to quantify conditional multivariate intensity measure distributions and generate realizations from them for ground-motion selection. The empirical correlations between intensity measures representing ground-motion amplitude, frequency content, duration, and cumulative effects are calculated using the RotD50 definition and compared with published models. The impact of intensity measure definition as in RotD50, RotD100, and the geometric mean is also scrutinized. The sensitivity of the results to the considered ground motion set and the reference ground motion model are addressed in the computations. The results are compared with those from only non-directivity and mixed data sets based on the NGA-West2 database. The results indicate that the adopted data set has the largest influence on the variability of the empirically computed correlation coefficients. Given the multiple sources that contribute to uncertainty in these calculations, the authors conclude that existing models for predicting median correlation coefficients based on mixed data sets are sufficient for use with directivity, non-directivity, and mixed ground motions.
{"title":"Effect of near-fault directivity pulses on ground-motion intensity measure correlations from the NGA-West2 data set","authors":"Karim Tarbali, Brendon A Bradley, Jack W Baker","doi":"10.1177/87552930231199059","DOIUrl":"https://doi.org/10.1177/87552930231199059","url":null,"abstract":"This article investigates the correlation coefficients of ground-motion intensity measures for ground motions containing near-fault directivity velocity pulses. These correlation coefficients are necessary to quantify conditional multivariate intensity measure distributions and generate realizations from them for ground-motion selection. The empirical correlations between intensity measures representing ground-motion amplitude, frequency content, duration, and cumulative effects are calculated using the RotD50 definition and compared with published models. The impact of intensity measure definition as in RotD50, RotD100, and the geometric mean is also scrutinized. The sensitivity of the results to the considered ground motion set and the reference ground motion model are addressed in the computations. The results are compared with those from only non-directivity and mixed data sets based on the NGA-West2 database. The results indicate that the adopted data set has the largest influence on the variability of the empirically computed correlation coefficients. Given the multiple sources that contribute to uncertainty in these calculations, the authors conclude that existing models for predicting median correlation coefficients based on mixed data sets are sufficient for use with directivity, non-directivity, and mixed ground motions.","PeriodicalId":11392,"journal":{"name":"Earthquake Spectra","volume":"28 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135959894","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-09-23DOI: 10.1177/87552930231195370
Mohammadtaghi Rahmani, Armin Barjani, Maria I Todorovska
The between-event variability in identified shear wave velocities of fitted four-layer beam models in the response of a 54-story steel-frame building during nine earthquakes over a period of 27 years (1992–2019) is investigated. Recorded response and simulated response by its digital twin (linear finite element model with fixed base) were used as input, that is, the real structure and its digital twin were identified. Two surrogate models were fitted, a Timoshenko beam and a shear beam. The waveform inversion of impulse response functions method, developed earlier by the authors, was used to fit the beam models. The coefficients of variation (C.V.) of the between-events variability in the wave velocity estimates of the four layers were analyzed and compared for the different cases of data (real structure versus digital twin), different surrogate models, and different locations on the floor where the motions were observed. The results showed that the variability of the digital twin was affected by the contamination of the response by torsion, which is not accounted for in the beam models, by the degree of geometric regularity of the structure and by how closely the beam model represented the nature of the building deformation (balance of shear and bending deformation). These effects were minor in comparison to the nonlinear effects (recoverable nonlinearity and permanent stiffness degradation), which were not present in the digital twin response. The C.V. for the real structure (about 3%–5%) was comparable for both beam models fitted.
{"title":"Variability in parameter estimation for a tall steel-frame building","authors":"Mohammadtaghi Rahmani, Armin Barjani, Maria I Todorovska","doi":"10.1177/87552930231195370","DOIUrl":"https://doi.org/10.1177/87552930231195370","url":null,"abstract":"The between-event variability in identified shear wave velocities of fitted four-layer beam models in the response of a 54-story steel-frame building during nine earthquakes over a period of 27 years (1992–2019) is investigated. Recorded response and simulated response by its digital twin (linear finite element model with fixed base) were used as input, that is, the real structure and its digital twin were identified. Two surrogate models were fitted, a Timoshenko beam and a shear beam. The waveform inversion of impulse response functions method, developed earlier by the authors, was used to fit the beam models. The coefficients of variation (C.V.) of the between-events variability in the wave velocity estimates of the four layers were analyzed and compared for the different cases of data (real structure versus digital twin), different surrogate models, and different locations on the floor where the motions were observed. The results showed that the variability of the digital twin was affected by the contamination of the response by torsion, which is not accounted for in the beam models, by the degree of geometric regularity of the structure and by how closely the beam model represented the nature of the building deformation (balance of shear and bending deformation). These effects were minor in comparison to the nonlinear effects (recoverable nonlinearity and permanent stiffness degradation), which were not present in the digital twin response. The C.V. for the real structure (about 3%–5%) was comparable for both beam models fitted.","PeriodicalId":11392,"journal":{"name":"Earthquake Spectra","volume":"56 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135965493","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-09-20DOI: 10.1177/87552930231190655
Nancy Ingabire Abayo, Ashly Cabas, Ellen Chamberlin, Brina Montoya
Liquefaction-induced lateral displacements represent a major geohazard in earthquake-prone regions, yet the uncertainty associated with their prediction remains notoriously high. Documented observations after recent earthquakes provide evidence that depositional environment-specific geologic conditions play a crucial role in liquefaction susceptibility, and in the severity and spatial extent of liquefaction-induced ground deformations. However, this evidence is largely qualitative in nature, which limits the potential to incorporate the effects of depositional processes and environments in the next generation of lateral spreading predictive models. This study provides a framework to quantitatively assess the relationship between depositional environment-specific geologic factors and lateral spreading by means of simple fluvial geomorphic facies models, geotechnical engineering data (e.g. Cone Penetration Test data), and geospatial analytics. Three hypotheses are introduced and tested using lateral spreading ground deformations observed following the 2011 Christchurch earthquake along the Avon and Heathcote rivers in New Zealand. The results from this study indicate that the presence of an active (i.e. with active sediment deposition) compared to inactive (e.g. abandoned) channels is the most important fluvial geomorphologic variable out of the three tested. The other two are associated with the location relative to the meander bend position, including location within the point bar (inside) or the cut bank (outside), and upstream versus downstream within a given point bar. Findings from this study show that more lateral spreading occurs within point bars, and upstream (within a given point bar) in simple meander bends. However, the presence of geomorphic complexities (e.g. cut banks connected to an incised channel or tributary and/or channel confinement) can challenge the unbiased quantification of the contribution of a single geomorphic variable to the observed lateral displacements. These findings can be applied to other fluvial environments outside of New Zealand, and the proposed framework can be implemented for other non-fluvial depositional settings.
{"title":"Fluvial geomorphic factors affecting liquefaction-induced lateral spreading","authors":"Nancy Ingabire Abayo, Ashly Cabas, Ellen Chamberlin, Brina Montoya","doi":"10.1177/87552930231190655","DOIUrl":"https://doi.org/10.1177/87552930231190655","url":null,"abstract":"Liquefaction-induced lateral displacements represent a major geohazard in earthquake-prone regions, yet the uncertainty associated with their prediction remains notoriously high. Documented observations after recent earthquakes provide evidence that depositional environment-specific geologic conditions play a crucial role in liquefaction susceptibility, and in the severity and spatial extent of liquefaction-induced ground deformations. However, this evidence is largely qualitative in nature, which limits the potential to incorporate the effects of depositional processes and environments in the next generation of lateral spreading predictive models. This study provides a framework to quantitatively assess the relationship between depositional environment-specific geologic factors and lateral spreading by means of simple fluvial geomorphic facies models, geotechnical engineering data (e.g. Cone Penetration Test data), and geospatial analytics. Three hypotheses are introduced and tested using lateral spreading ground deformations observed following the 2011 Christchurch earthquake along the Avon and Heathcote rivers in New Zealand. The results from this study indicate that the presence of an active (i.e. with active sediment deposition) compared to inactive (e.g. abandoned) channels is the most important fluvial geomorphologic variable out of the three tested. The other two are associated with the location relative to the meander bend position, including location within the point bar (inside) or the cut bank (outside), and upstream versus downstream within a given point bar. Findings from this study show that more lateral spreading occurs within point bars, and upstream (within a given point bar) in simple meander bends. However, the presence of geomorphic complexities (e.g. cut banks connected to an incised channel or tributary and/or channel confinement) can challenge the unbiased quantification of the contribution of a single geomorphic variable to the observed lateral displacements. These findings can be applied to other fluvial environments outside of New Zealand, and the proposed framework can be implemented for other non-fluvial depositional settings.","PeriodicalId":11392,"journal":{"name":"Earthquake Spectra","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136309254","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-09-16DOI: 10.1177/87552930231192463
Victor Moises Hernández-Aguirre, Roberto Paolucci, Francisco José Sánchez-Sesma, Ilario Mazzieri
In this study, a 3D physics-based numerical approach, based on the spectral element numerical code SPEED, is used to simulate seismic wave propagation due to a local earthquake in the Mexico City area. The availability of detailed geological, geophysical, geotechnical, and seismological data allowed for the creation of a large-scale (60 km × 60 km in plan, 10 km in depth) heterogeneous 3D numerical model of the Mexico City area, dimensioned to accurately propagate frequencies up to about 1.3 Hz. The results of numerical simulations are validated against the ground motion recordings of the July 17, 2019, Mw3.2 earthquake, with peak ground acceleration exceeding 0.3 g about 1 km away from the epicenter. A good agreement with records is found, quantitatively evaluated through goodness-of-fit checks. Furthermore, for the lake zone, the simulated decay trend of the peak ground velocity with epicentral distance is reasonably close to the observations, for both horizontal and vertical components. In spite of some limitations, the simulations are successful to provide a realistic picture of seismic wave propagation both in the hill and in the lake zones of Mexico City, including the onset of long-duration quasi-monochromatic ground motion in the basin, with strong amplification at low frequencies (between 0.4 and 0.7 Hz). The numerical results also suggest that surface waves, with predominant prograde particle motion at the ground surface and large ellipticities, dominate the wavefield in the lake zone. Based on these positive outcomes, we conclude that this numerical model may be useful for both a better insight into the seismic response of the Valley of Mexico and the simulation of ground motions during larger-magnitude earthquakes, to generate improved seismic damage scenarios in Mexico City.
{"title":"Three-dimensional numerical modeling of ground motion in the Valley of Mexico: A case study from the Mw3.2 earthquake of July 17, 2019","authors":"Victor Moises Hernández-Aguirre, Roberto Paolucci, Francisco José Sánchez-Sesma, Ilario Mazzieri","doi":"10.1177/87552930231192463","DOIUrl":"https://doi.org/10.1177/87552930231192463","url":null,"abstract":"In this study, a 3D physics-based numerical approach, based on the spectral element numerical code SPEED, is used to simulate seismic wave propagation due to a local earthquake in the Mexico City area. The availability of detailed geological, geophysical, geotechnical, and seismological data allowed for the creation of a large-scale (60 km × 60 km in plan, 10 km in depth) heterogeneous 3D numerical model of the Mexico City area, dimensioned to accurately propagate frequencies up to about 1.3 Hz. The results of numerical simulations are validated against the ground motion recordings of the July 17, 2019, Mw3.2 earthquake, with peak ground acceleration exceeding 0.3 g about 1 km away from the epicenter. A good agreement with records is found, quantitatively evaluated through goodness-of-fit checks. Furthermore, for the lake zone, the simulated decay trend of the peak ground velocity with epicentral distance is reasonably close to the observations, for both horizontal and vertical components. In spite of some limitations, the simulations are successful to provide a realistic picture of seismic wave propagation both in the hill and in the lake zones of Mexico City, including the onset of long-duration quasi-monochromatic ground motion in the basin, with strong amplification at low frequencies (between 0.4 and 0.7 Hz). The numerical results also suggest that surface waves, with predominant prograde particle motion at the ground surface and large ellipticities, dominate the wavefield in the lake zone. Based on these positive outcomes, we conclude that this numerical model may be useful for both a better insight into the seismic response of the Valley of Mexico and the simulation of ground motions during larger-magnitude earthquakes, to generate improved seismic damage scenarios in Mexico City.","PeriodicalId":11392,"journal":{"name":"Earthquake Spectra","volume":"16 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135306578","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-09-15DOI: 10.1177/87552930231190687
Biniam Tekle Teweldebrhan, Katsuichiro Goda, Raffaele De Risi, Solomon Tesfamariam
The cross-laminated timber coupled wall (CLT-CW) system, a recently proposed timber-based structural system, has limited understanding of its seismic performance. The existing research in probabilistic seismic fragility assessment (PSFA) of CLT buildings reveals gap, particularly regarding comprehensive evaluation of CLT-CW systems and the impact of its various design parameters. To fully describe the state of the post-earthquake performance of structures, state-of-the-art studies recommend using multi-variate fragility analysis. Accordingly, this article presents a bi-variate PSFA of CLT-CW systems using two engineering demand parameters: the maximum and residual inter-story drift ratios. For the seismicity of Vancouver, British Columbia, Canada, 11 prototype buildings are evaluated considering different design parameters: coupling ratio, coupling beam shear force profile, CLT wall configuration, building story height, and ductility-related seismic force modification factor. Bi-dimensional numerical models of the systems are developed in OpenSees, and incremental dynamic analyses are performed using 30 ground motion records. Three limit state capacities and three limit state function combinations are utilized to develop probabilistic seismic fragility curves. The fragility curves under the different limit state function combinations are compared, and the effect of the different design parameters is investigated. This study contributes to a deeper understanding of the seismic performance of CLT-CW systems, assisting engineers and researchers in assessing seismic risk and developing seismic-resilient structures.
{"title":"Multi-variate seismic fragility assessment of CLT coupled wall systems","authors":"Biniam Tekle Teweldebrhan, Katsuichiro Goda, Raffaele De Risi, Solomon Tesfamariam","doi":"10.1177/87552930231190687","DOIUrl":"https://doi.org/10.1177/87552930231190687","url":null,"abstract":"The cross-laminated timber coupled wall (CLT-CW) system, a recently proposed timber-based structural system, has limited understanding of its seismic performance. The existing research in probabilistic seismic fragility assessment (PSFA) of CLT buildings reveals gap, particularly regarding comprehensive evaluation of CLT-CW systems and the impact of its various design parameters. To fully describe the state of the post-earthquake performance of structures, state-of-the-art studies recommend using multi-variate fragility analysis. Accordingly, this article presents a bi-variate PSFA of CLT-CW systems using two engineering demand parameters: the maximum and residual inter-story drift ratios. For the seismicity of Vancouver, British Columbia, Canada, 11 prototype buildings are evaluated considering different design parameters: coupling ratio, coupling beam shear force profile, CLT wall configuration, building story height, and ductility-related seismic force modification factor. Bi-dimensional numerical models of the systems are developed in OpenSees, and incremental dynamic analyses are performed using 30 ground motion records. Three limit state capacities and three limit state function combinations are utilized to develop probabilistic seismic fragility curves. The fragility curves under the different limit state function combinations are compared, and the effect of the different design parameters is investigated. This study contributes to a deeper understanding of the seismic performance of CLT-CW systems, assisting engineers and researchers in assessing seismic risk and developing seismic-resilient structures.","PeriodicalId":11392,"journal":{"name":"Earthquake Spectra","volume":"2012 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135396579","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-09-13DOI: 10.1177/87552930231179493
Tansu Gokce, Rory E White, Adam J Crewe, Matt Dietz, Tony Horseman, Luiza Dihoru
Seismic response analyses of structures have conventionally used the peak ground acceleration or spectral acceleration as an intensity measure to estimate the engineering demand parameters. An extensive shaking table test program was carried out on a quarter-sized advanced gas-cooled reactor (AGR) core model to investigate the global dynamic behavior of the system with degraded graphite components while subjected to seismic excitation. Evaluation of the most widely considered intensity measures, with respect to their capability for predicting the seismic response of an AGR core–like structure, is performed. Twenty intensity measures of 16 distinct seismic input motions are formulated and correlated, with experimental measurements describing the dynamic response of the reactor core model. Linear correlations are constructed for each intensity measure to statistically determine the best metric for predicting the seismic response of the AGR core model, and statistical analysis indicates that the acceleration spectrum intensity (ASI) is best suited to characterize and describe the structural demand of an AGR core-like structure when subjected to seismic loading. A response prediction tool is developed, based on empirically derived linear correlations, to estimate column distortions and determine the critical input motion for further experimental and numerical studies. Statistical analysis indicates that predicted column distortions, compared against direct experimental displacements, are significant, repeatable, and accurate.
{"title":"Seismic response prediction using intensity measures: Graphite nuclear reactor core model case study","authors":"Tansu Gokce, Rory E White, Adam J Crewe, Matt Dietz, Tony Horseman, Luiza Dihoru","doi":"10.1177/87552930231179493","DOIUrl":"https://doi.org/10.1177/87552930231179493","url":null,"abstract":"Seismic response analyses of structures have conventionally used the peak ground acceleration or spectral acceleration as an intensity measure to estimate the engineering demand parameters. An extensive shaking table test program was carried out on a quarter-sized advanced gas-cooled reactor (AGR) core model to investigate the global dynamic behavior of the system with degraded graphite components while subjected to seismic excitation. Evaluation of the most widely considered intensity measures, with respect to their capability for predicting the seismic response of an AGR core–like structure, is performed. Twenty intensity measures of 16 distinct seismic input motions are formulated and correlated, with experimental measurements describing the dynamic response of the reactor core model. Linear correlations are constructed for each intensity measure to statistically determine the best metric for predicting the seismic response of the AGR core model, and statistical analysis indicates that the acceleration spectrum intensity (ASI) is best suited to characterize and describe the structural demand of an AGR core-like structure when subjected to seismic loading. A response prediction tool is developed, based on empirically derived linear correlations, to estimate column distortions and determine the critical input motion for further experimental and numerical studies. Statistical analysis indicates that predicted column distortions, compared against direct experimental displacements, are significant, repeatable, and accurate.","PeriodicalId":11392,"journal":{"name":"Earthquake Spectra","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135784305","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-09-13DOI: 10.1177/87552930231194048
Catalina Yepes-Estrada, Alejandro Calderon, Catarina Costa, Helen Crowley, Jamal Dabbeek, Maria Camila Hoyos, Luis Martins, Nicole Paul, Anirudh Rao, Vitor Silva
The global building exposure model is a mosaic of local and regional models with information regarding the residential, commercial, and industrial building stock at the smallest available administrative division of each country and includes details about the number of buildings, number of occupants, vulnerability characteristics, average built-up area, and average replacement cost. We aimed for a bottom-up approach at the global scale, using national statistics, socio-economic data, and local datasets. This model allows the identification of the most common types of construction worldwide, regions with large fractions of informal construction, and areas prone to earthquakes with a high concentration of population and building stock. The mosaic of exposure models presented herein can be used for the assessment of probabilistic seismic risk and earthquake scenarios. Information at the global, regional, and national levels is available through a public repository ( https://github.com/gem/global_exposure_model ), which will be used to maintain, update and improve the models.
{"title":"Global building exposure model for earthquake risk assessment","authors":"Catalina Yepes-Estrada, Alejandro Calderon, Catarina Costa, Helen Crowley, Jamal Dabbeek, Maria Camila Hoyos, Luis Martins, Nicole Paul, Anirudh Rao, Vitor Silva","doi":"10.1177/87552930231194048","DOIUrl":"https://doi.org/10.1177/87552930231194048","url":null,"abstract":"The global building exposure model is a mosaic of local and regional models with information regarding the residential, commercial, and industrial building stock at the smallest available administrative division of each country and includes details about the number of buildings, number of occupants, vulnerability characteristics, average built-up area, and average replacement cost. We aimed for a bottom-up approach at the global scale, using national statistics, socio-economic data, and local datasets. This model allows the identification of the most common types of construction worldwide, regions with large fractions of informal construction, and areas prone to earthquakes with a high concentration of population and building stock. The mosaic of exposure models presented herein can be used for the assessment of probabilistic seismic risk and earthquake scenarios. Information at the global, regional, and national levels is available through a public repository ( https://github.com/gem/global_exposure_model ), which will be used to maintain, update and improve the models.","PeriodicalId":11392,"journal":{"name":"Earthquake Spectra","volume":"21 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135736415","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-09-09DOI: 10.1177/87552930231198243
Pavan Chigullapally, Liam Wotherspoon, Max T Stephens, Lucas S Hogan
This article presents the recorded and modeled strong-motion response of a long (1.35 km) bridge located in Wellington, New Zealand during multiple sequential earthquakes. These were some of the first recordings of this kind for a New Zealand highway bridge and add to the limited database of bridge superstructure strong-motion responses recorded worldwide. The bridge experienced little damage during the earthquakes; however, analysis of the recorded responses showed the fundamental period of the bridge varied by up to 15% across these events, highlighting the system softening that can develop without any significant structural damage. Numerical models of a single bridge pier using a p-y spring foundation modeling approach were able to represent the changes in the recorded bridge pier response across the events based on multiple response metrics, suggesting that system softening was primarily due to nonlinear soil response and concrete cracking. A sensitivity analysis showed that concrete strength and the characteristics of the upper soil layers had the largest influence on the model response. Given the presence of several strong-motion stations in close vicinity to the bridge, the sensitivity to ground-motion input was also investigated. This was shown to have a more significant influence on the modeled response than the other modeling uncertainties evaluated here, with the variability in estimated deformations highlighting the difficulties involved in the back analysis of the response of structures.
{"title":"Recorded and modeled response of the Thorndon Overbridge during multiple earthquakes","authors":"Pavan Chigullapally, Liam Wotherspoon, Max T Stephens, Lucas S Hogan","doi":"10.1177/87552930231198243","DOIUrl":"https://doi.org/10.1177/87552930231198243","url":null,"abstract":"This article presents the recorded and modeled strong-motion response of a long (1.35 km) bridge located in Wellington, New Zealand during multiple sequential earthquakes. These were some of the first recordings of this kind for a New Zealand highway bridge and add to the limited database of bridge superstructure strong-motion responses recorded worldwide. The bridge experienced little damage during the earthquakes; however, analysis of the recorded responses showed the fundamental period of the bridge varied by up to 15% across these events, highlighting the system softening that can develop without any significant structural damage. Numerical models of a single bridge pier using a p-y spring foundation modeling approach were able to represent the changes in the recorded bridge pier response across the events based on multiple response metrics, suggesting that system softening was primarily due to nonlinear soil response and concrete cracking. A sensitivity analysis showed that concrete strength and the characteristics of the upper soil layers had the largest influence on the model response. Given the presence of several strong-motion stations in close vicinity to the bridge, the sensitivity to ground-motion input was also investigated. This was shown to have a more significant influence on the modeled response than the other modeling uncertainties evaluated here, with the variability in estimated deformations highlighting the difficulties involved in the back analysis of the response of structures.","PeriodicalId":11392,"journal":{"name":"Earthquake Spectra","volume":"78 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136192698","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-09-09DOI: 10.1177/87552930231195640
S Vishal Gupta, Imtiyaz A Parvez, Prosanta K Khan
Deep sedimentary valleys entrap and amplify seismic waves, which is further responsible for site-specific amplification over the allied region. Kashmir valley is a deep and active sedimentary basin in the northwest portion of the Himalayan lap. To characterize the site response for the intermountain Kashmir valley for the first time, we acquire single station microtremor measurements using Lennartz (three components/5s seismometer) at 141 sites with a grid of (5 km × 5 km) and two-dimensional (2D) array measurements using seven units of recording station of different geometry pattern at 38 sites across different lithological setup within the basin. We present here (1) a first-order predominant fundamental frequency (0.21–10.19 Hz) and subsequent sedimentary thickness maps for the entire valley, reflecting deep deposition with spatial heterogeneity in the area using the horizontal-to-vertical spectral ratio (HVSR) technique; (2) spatial classification of generated HVSR curves linking subsurface geomorphology and post strong ground-motion scenario in the valley; (3) extraction of the best dispersion characteristics of Rayleigh waves (fundamental mode) from all recorded vertical signals at each array site using frequency–wavenumber (F-K) method with an emphasis on signal synchronicity; and (4) retrieval of one-dimensional (1D) shear wave velocity ( V S ) profiles across the valley from the inversion of dispersion curves using the neighborhood algorithm. Distinct model parameterizations were tested for the inversion to achieve the optimal inversion misfit. The collocated 1D V S profiles are consistent with newly drilled borehole logs information. Besides, the presented first-ever ambient noise survey–based site response study meets the objectives of site-specific seismic hazard and risk analysis of the Kashmir valley at the regional scale.
深沉积谷圈闭和放大地震波，这进一步负责在相关地区特定地点的放大。克什米尔河谷是喜马拉雅环带西北部的一个深而活跃的沉积盆地。为了首次表征克什米尔山间山谷的现场响应，我们利用Lennartz(三分量/5s地震仪)在141个站点(5 km × 5 km)进行了单站微震测量，并在盆地内不同岩性设置的38个站点使用7个不同几何形状的记录站进行了二维(2D)阵列测量。本文(1)利用水平-垂直谱比(HVSR)技术绘制了整个河谷的一阶优势基频(0.21-10.19 Hz)和随后的沉积厚度图，反映了该地区具有空间异质性的深层沉积;(2)连接河谷地下地貌与强震后情景的生成的高通量曲线空间分类;(3)利用频率-波数(F-K)方法从各阵点记录的所有垂直信号中提取瑞利波(基模)的最佳色散特征，重点考虑信号同步性;(4)利用邻域算法从频散曲线反演中反演河谷剖面的一维横波速度(V S)。为了获得最优的反演失配，对不同的模型参数化进行了测试。配置的一维V - S剖面与新钻探的井眼测井信息一致。此外，本文首次提出了基于环境噪声调查的场地响应研究，满足了克什米尔河谷区域尺度上场地特定地震灾害和风险分析的目标。
{"title":"Site response analysis beneath the Kashmir basin (NW Himalaya) using ambient noise","authors":"S Vishal Gupta, Imtiyaz A Parvez, Prosanta K Khan","doi":"10.1177/87552930231195640","DOIUrl":"https://doi.org/10.1177/87552930231195640","url":null,"abstract":"Deep sedimentary valleys entrap and amplify seismic waves, which is further responsible for site-specific amplification over the allied region. Kashmir valley is a deep and active sedimentary basin in the northwest portion of the Himalayan lap. To characterize the site response for the intermountain Kashmir valley for the first time, we acquire single station microtremor measurements using Lennartz (three components/5s seismometer) at 141 sites with a grid of (5 km × 5 km) and two-dimensional (2D) array measurements using seven units of recording station of different geometry pattern at 38 sites across different lithological setup within the basin. We present here (1) a first-order predominant fundamental frequency (0.21–10.19 Hz) and subsequent sedimentary thickness maps for the entire valley, reflecting deep deposition with spatial heterogeneity in the area using the horizontal-to-vertical spectral ratio (HVSR) technique; (2) spatial classification of generated HVSR curves linking subsurface geomorphology and post strong ground-motion scenario in the valley; (3) extraction of the best dispersion characteristics of Rayleigh waves (fundamental mode) from all recorded vertical signals at each array site using frequency–wavenumber (F-K) method with an emphasis on signal synchronicity; and (4) retrieval of one-dimensional (1D) shear wave velocity ( V S ) profiles across the valley from the inversion of dispersion curves using the neighborhood algorithm. Distinct model parameterizations were tested for the inversion to achieve the optimal inversion misfit. The collocated 1D V S profiles are consistent with newly drilled borehole logs information. Besides, the presented first-ever ambient noise survey–based site response study meets the objectives of site-specific seismic hazard and risk analysis of the Kashmir valley at the regional scale.","PeriodicalId":11392,"journal":{"name":"Earthquake Spectra","volume":"28 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136191874","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-09-08DOI: 10.1177/87552930231194563
Yi-Chang Chu, Cheng-Tao Yang, Chin-Hsun Yeh, Szu-Yun Lin
The accessibility of road systems is key to facilitating emergency responses in the aftermath of a severe disaster. However, collapsed buildings and debris may cause road blockages, impeding disaster relief efforts after a major earthquake. This study aims to present an efficient and generic assessment method for evaluating the risk of road blockage due to seismic event-induced debris. First, the probability of building collapse in city blocks and the effects of building debris after an earthquake scenario are estimated based on building types, seismic design levels, soil conditions, and local ground motion intensities of the adopted earthquake scenario. Subsequently, the seismic risk of road sections is assessed by considering the collective effects of nearby street profiles, including building materials, heights, and the shape factor of city blocks. This study considers various interpretive building environment parameters and employs three post-earthquake risk indexes to represent different aspects of seismic risk of a road system, including passability loss, affected road length ratio, and road interruption severity. To demonstrate the applicability of the proposed method, the rescue routes in Taipei City, Taiwan, are adopted as a case study. The proposed method can effectively distinguish high-risk roads as valuable information, and the results have been provided to local government disaster relief units for reference.
{"title":"Multi-index assessment of road blockage risk due to seismic event-induced building debris","authors":"Yi-Chang Chu, Cheng-Tao Yang, Chin-Hsun Yeh, Szu-Yun Lin","doi":"10.1177/87552930231194563","DOIUrl":"https://doi.org/10.1177/87552930231194563","url":null,"abstract":"The accessibility of road systems is key to facilitating emergency responses in the aftermath of a severe disaster. However, collapsed buildings and debris may cause road blockages, impeding disaster relief efforts after a major earthquake. This study aims to present an efficient and generic assessment method for evaluating the risk of road blockage due to seismic event-induced debris. First, the probability of building collapse in city blocks and the effects of building debris after an earthquake scenario are estimated based on building types, seismic design levels, soil conditions, and local ground motion intensities of the adopted earthquake scenario. Subsequently, the seismic risk of road sections is assessed by considering the collective effects of nearby street profiles, including building materials, heights, and the shape factor of city blocks. This study considers various interpretive building environment parameters and employs three post-earthquake risk indexes to represent different aspects of seismic risk of a road system, including passability loss, affected road length ratio, and road interruption severity. To demonstrate the applicability of the proposed method, the rescue routes in Taipei City, Taiwan, are adopted as a case study. The proposed method can effectively distinguish high-risk roads as valuable information, and the results have been provided to local government disaster relief units for reference.","PeriodicalId":11392,"journal":{"name":"Earthquake Spectra","volume":"24 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136361779","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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