Pub Date : 2024-10-12DOI: 10.1016/j.soildyn.2024.109003
Yu-Liang Lin , Li Lu , Xiao-Bin Chen , Yuan Xue , Zhi-meng Wang
Multi-stage anchoring lattice beam is widely used to support high slope in high earthquake intensity area, while the seismic behavior and interaction are not very clear. The previous studies mainly focused on a single-stage slope, while the analysis of multi-stage effect on the seismic response of anchoring lattice beam is lacking. Subsequently, a shaking table experiment was carried out to investigate the dynamic characteristics and seismic responses of a three-stage slope supported by an anchoring lattice beam. The displacement mode and the residual displacement are observed by Digital Image Correlation (DIC) technology. Kobe and Landers ground motions were input in shaking table test with an increasing order of shaking intensity. The original Kobe motion was applied at the last sequence to investigate the effect of frequency characteristic of ground motion. The results show that the acceleration response increases nonlinearly along the height of three-stage slope, and a reduction of acceleration response is observed at platform. The energy within a frequency band close to natural frequency of three-stage slope is especially amplified. The anchor takes more responsibility to resist the seismic loading, and decreases the earth pressure behind lattice beam. By setting multiple stages, the acceleration amplification and seismic earth pressure are reduced effectively. The intensity and the frequency characteristic of seismic motion affect the axial strain of anchor. The potential local failure and the frequency characteristic of seismic motion are suggested to be considered in seismic design.
{"title":"Shaking table experiment on seismic response of a three-stage slope supported by anchoring lattice beam","authors":"Yu-Liang Lin , Li Lu , Xiao-Bin Chen , Yuan Xue , Zhi-meng Wang","doi":"10.1016/j.soildyn.2024.109003","DOIUrl":"10.1016/j.soildyn.2024.109003","url":null,"abstract":"<div><div>Multi-stage anchoring lattice beam is widely used to support high slope in high earthquake intensity area, while the seismic behavior and interaction are not very clear. The previous studies mainly focused on a single-stage slope, while the analysis of multi-stage effect on the seismic response of anchoring lattice beam is lacking. Subsequently, a shaking table experiment was carried out to investigate the dynamic characteristics and seismic responses of a three-stage slope supported by an anchoring lattice beam. The displacement mode and the residual displacement are observed by Digital Image Correlation (DIC) technology. Kobe and Landers ground motions were input in shaking table test with an increasing order of shaking intensity. The original Kobe motion was applied at the last sequence to investigate the effect of frequency characteristic of ground motion. The results show that the acceleration response increases nonlinearly along the height of three-stage slope, and a reduction of acceleration response is observed at platform. The energy within a frequency band close to natural frequency of three-stage slope is especially amplified. The anchor takes more responsibility to resist the seismic loading, and decreases the earth pressure behind lattice beam. By setting multiple stages, the acceleration amplification and seismic earth pressure are reduced effectively. The intensity and the frequency characteristic of seismic motion affect the axial strain of anchor. The potential local failure and the frequency characteristic of seismic motion are suggested to be considered in seismic design.</div></div>","PeriodicalId":49502,"journal":{"name":"Soil Dynamics and Earthquake Engineering","volume":"187 ","pages":"Article 109003"},"PeriodicalIF":4.2,"publicationDate":"2024-10-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142420010","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 : 2024-10-11DOI: 10.1016/j.soildyn.2024.109016
G. Pianese , N. Van Engelen , H. Toopchi-Nezhad , G. Milani
Elastomeric isolators are commonly used for seismic isolation. Typically, they are composed of alternating rubber pads and steel laminas. The composite action provides horizontal flexibility through the rubber and vertical and rotational stiffness through the steel. However, due to costs, they are mainly limited to use in strategic, nonresidential structures, especially in developing countries. A new elastomeric device, the fiber-reinforced elastomeric isolator (FREI), has been developed using fiber layers instead of steel laminas, reducing costs. FREIs offer bonded (traditional), unbonded, and partially bonded applications. In the unbonded setup, FREIs are placed between structures and foundations without any bonding or fastening. The shear load is transferred through the friction generated between the isolator and the structure surfaces, improving the seismic performances and the damping ability compared to the same device in a bonded condition. However, they can't resist vertical tension. The partially bonded approach addresses this by partially attaching the contact surfaces of the device to connection steel plates, retaining the advantages of both bonded and unbonded methods. Central to the efficacy of these isolators is the rubber material itself. Natural rubber (NR) is the most used, but artificial rubber is promising for the fabrication of isolators because NR has a poor damping performance, it is vulnerable to quick aging, and its industrial production is of concern. Factors such as escalating demand, price fluctuations, high labor costs, trade policies, and a ban on deforestation have made NR production unreliable.
This paper presents an in-depth investigation of circular high-damping FREIs in both partially bonded and unbonded applications. The study employs a combined numerical and experimental approach. It provides a detailed explanation of the design process, numerical modeling, and experimental characterization for both the rubber material and the seismic devices, highlighting the advantages of design optimization based on preliminary numerical results. This methodology can serve as a valuable example, offering significant help to manufacturers and engineers. Additionally, a novel simplified analytical model is introduced for the employment of unbonded and partially bonded FREIs in structural applications, based on the fitting of cyclic shear tests used for the characterization of the dynamic properties of the elastomeric devices.
弹性隔震层通常用于隔震。通常，它们由橡胶垫和钢板交替组成。这种复合作用通过橡胶提供水平弹性，通过钢提供垂直和旋转刚度。然而，由于成本原因，它们主要局限于用于战略性非住宅结构，尤其是在发展中国家。纤维增强弹性体隔振器（FREI）是一种新型弹性体装置，它使用纤维层代替钢层板，从而降低了成本。纤维增强弹性体隔振器可提供粘合（传统）、非粘合和部分粘合应用。在无粘结设置中，FREI 被放置在结构和地基之间，无需任何粘结或紧固。剪切荷载通过隔振器和结构表面之间产生的摩擦力传递，与粘结状态下的相同装置相比，抗震性能和阻尼能力都有所提高。但是，它们不能抵抗垂直拉力。部分粘结方法通过将隔震装置的接触面部分固定在连接钢板上来解决这一问题，同时保留了粘结和非粘结方法的优点。橡胶材料本身是这些隔振器功效的关键。天然橡胶（NR）是最常用的材料，但人造橡胶在制作隔振器方面也大有可为，因为天然橡胶的阻尼性能较差，容易快速老化，其工业生产也令人担忧。需求升级、价格波动、劳动力成本高、贸易政策和禁止砍伐森林等因素使得 NR 的生产变得不可靠。本文对部分粘接和非粘接应用中的圆形高阻尼 FREI 进行了深入研究。研究采用了数值和实验相结合的方法。它详细解释了橡胶材料和抗震装置的设计过程、数值建模和实验表征，强调了基于初步数值结果进行优化设计的优势。这种方法可作为宝贵的范例，为制造商和工程师提供重要帮助。此外，根据用于表征弹性装置动态特性的循环剪切试验的拟合结果，介绍了在结构应用中使用无粘结和部分粘结 FREIs 的新型简化分析模型。
{"title":"An experimental and numerical insight into the unbonded and partially bonded high-damping fiber-reinforced elastomeric isolators","authors":"G. Pianese , N. Van Engelen , H. Toopchi-Nezhad , G. Milani","doi":"10.1016/j.soildyn.2024.109016","DOIUrl":"10.1016/j.soildyn.2024.109016","url":null,"abstract":"<div><div>Elastomeric isolators are commonly used for seismic isolation. Typically, they are composed of alternating rubber pads and steel laminas. The composite action provides horizontal flexibility through the rubber and vertical and rotational stiffness through the steel. However, due to costs, they are mainly limited to use in strategic, nonresidential structures, especially in developing countries. A new elastomeric device, the fiber-reinforced elastomeric isolator (FREI), has been developed using fiber layers instead of steel laminas, reducing costs. FREIs offer bonded (traditional), unbonded, and partially bonded applications. In the unbonded setup, FREIs are placed between structures and foundations without any bonding or fastening. The shear load is transferred through the friction generated between the isolator and the structure surfaces, improving the seismic performances and the damping ability compared to the same device in a bonded condition. However, they can't resist vertical tension. The partially bonded approach addresses this by partially attaching the contact surfaces of the device to connection steel plates, retaining the advantages of both bonded and unbonded methods. Central to the efficacy of these isolators is the rubber material itself. Natural rubber (NR) is the most used, but artificial rubber is promising for the fabrication of isolators because NR has a poor damping performance, it is vulnerable to quick aging, and its industrial production is of concern. Factors such as escalating demand, price fluctuations, high labor costs, trade policies, and a ban on deforestation have made NR production unreliable.</div><div>This paper presents an in-depth investigation of circular high-damping FREIs in both partially bonded and unbonded applications. The study employs a combined numerical and experimental approach. It provides a detailed explanation of the design process, numerical modeling, and experimental characterization for both the rubber material and the seismic devices, highlighting the advantages of design optimization based on preliminary numerical results. This methodology can serve as a valuable example, offering significant help to manufacturers and engineers. Additionally, a novel simplified analytical model is introduced for the employment of unbonded and partially bonded FREIs in structural applications, based on the fitting of cyclic shear tests used for the characterization of the dynamic properties of the elastomeric devices.</div></div>","PeriodicalId":49502,"journal":{"name":"Soil Dynamics and Earthquake Engineering","volume":"187 ","pages":"Article 109016"},"PeriodicalIF":4.2,"publicationDate":"2024-10-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142420011","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-11DOI: 10.1016/j.soildyn.2024.109021
Insub Choi , Han Yong Lee , Byung Kwan Oh
This study proposes a method for predicting the seismic response of structures using seismic information and structural properties. In the proposed method, the relationship between seismic and structural characteristics and seismic responses was investigated using a convolutional neural network (CNN) to predict the seismic response. Spectral acceleration (Sa) calculated from the seismic wave was selected as seismic information used in CNN-based seismic response prediction techniques. The study introduced seismic information and structural properties, which correspond to the parameters to express the structure's unique characteristics or nonlinear hysteretic behaviors that determine the response characteristics of the structure subjected to seismic waves. Meanwhile, Sa and structural properties were utilized to constitute the input map of CNN and predict the maximum inter-story drift ratio that corresponds to the output of CNN. As data corresponding to the period range of interest rather than a scalar value for a specific period, Sa is rearranged in matrix form to constitute the input map of CNN. Structural properties are also placed in the input map of CNN as scalar values are converted into conditional vectors. To confirm the validity of the proposed method, multiple CNN-based models with changes in the information of the input map are presented, and their prediction performances are compared. Furthermore, CNN-based models that additionally consider seismic intensity measures are presented, and their influences on seismic response prediction performance are analyzed. In addition, a vast number of linear and nonlinear structures were generated, and seismic responses extracted via seismic analysis of multiple earthquakes were used to create datasets for training the presented models. The prediction performance of the presented models trained using the datasets was compared. The validity of the simultaneous use of structural properties with Sa, the introduction of conditional vectors, the additional use of seismic intensity measures, and their contributions to improving prediction performance were also examined.
{"title":"Convolutional neural network-based seismic response prediction method using spectral acceleration of earthquakes and conditional vector of structural property","authors":"Insub Choi , Han Yong Lee , Byung Kwan Oh","doi":"10.1016/j.soildyn.2024.109021","DOIUrl":"10.1016/j.soildyn.2024.109021","url":null,"abstract":"<div><div>This study proposes a method for predicting the seismic response of structures using seismic information and structural properties. In the proposed method, the relationship between seismic and structural characteristics and seismic responses was investigated using a convolutional neural network (CNN) to predict the seismic response. Spectral acceleration (Sa) calculated from the seismic wave was selected as seismic information used in CNN-based seismic response prediction techniques. The study introduced seismic information and structural properties, which correspond to the parameters to express the structure's unique characteristics or nonlinear hysteretic behaviors that determine the response characteristics of the structure subjected to seismic waves. Meanwhile, Sa and structural properties were utilized to constitute the input map of CNN and predict the maximum inter-story drift ratio that corresponds to the output of CNN. As data corresponding to the period range of interest rather than a scalar value for a specific period, Sa is rearranged in matrix form to constitute the input map of CNN. Structural properties are also placed in the input map of CNN as scalar values are converted into conditional vectors. To confirm the validity of the proposed method, multiple CNN-based models with changes in the information of the input map are presented, and their prediction performances are compared. Furthermore, CNN-based models that additionally consider seismic intensity measures are presented, and their influences on seismic response prediction performance are analyzed. In addition, a vast number of linear and nonlinear structures were generated, and seismic responses extracted via seismic analysis of multiple earthquakes were used to create datasets for training the presented models. The prediction performance of the presented models trained using the datasets was compared. The validity of the simultaneous use of structural properties with Sa, the introduction of conditional vectors, the additional use of seismic intensity measures, and their contributions to improving prediction performance were also examined.</div></div>","PeriodicalId":49502,"journal":{"name":"Soil Dynamics and Earthquake Engineering","volume":"187 ","pages":"Article 109021"},"PeriodicalIF":4.2,"publicationDate":"2024-10-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142419971","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-10DOI: 10.1016/j.soildyn.2024.109009
Michele Placido Antonio Gatto , Francesco Castelli , Valentina Lentini , Lorella Montrasio
This study presents the use of Artificial Intelligence (AI) to predict the dynamic behaviour of fine-grained soils of South Italy based on a detailed laboratory investigation. The investigation consists of Resonant Column (RC), Cyclic Torsional Shear (CTS), and Cyclic Triaxial (CTx) tests performed on 25 specimens of fine-grained soils retrieved from 11 sites in Sicily (South Italy). To develop accurate predictive models of soil dynamic properties, essential for site response analyses and dynamic soil-structure interaction, various regression techniques were applied. These techniques range from Multiple Linear Regression (MLR) to more complex AI methods, specifically Machine Learning (ML) and Deep Learning (DL) based on FeedForward Neural networks (FFN). Three predictive models were developed to derive strain-dependent shear modulus (G), damping ratio (D), and normalized shear modulus (G/G0), using four inputs: shear strain (γ), plasticity index (PI), confining pressure (p’0), and the Over Consolidation Ratio (OCR). To determine the optimal FFN topology, 1350 networks were developed by varying hidden layers (1–3), hidden neurons (1–50 per layer), and activation functions (ReLU, sigmoid and hyperbolic tangent). Hybrid FFN optimised through Genetic Algorithm and Particle Swarm Optimization techniques were also investigated. Single-hidden layer networks with fewer than 15 neurons provided acceptable predictions (R2test of 0.97 for G-γ, 0.93 for G/G0-γ, and 0.85 for D-γ models). Multiple-hidden layer networks yielded higher accuracy for G and D models but are more complex for practical use. The FFN models outperformed MLR and other established empirical formulations, highlighting the site-specificity of the modelling parameters of the latter.
{"title":"AI-driven predictions of the dynamic properties of fine-grained soils in South Italy based on laboratory testing","authors":"Michele Placido Antonio Gatto , Francesco Castelli , Valentina Lentini , Lorella Montrasio","doi":"10.1016/j.soildyn.2024.109009","DOIUrl":"10.1016/j.soildyn.2024.109009","url":null,"abstract":"<div><div>This study presents the use of Artificial Intelligence (AI) to predict the dynamic behaviour of fine-grained soils of South Italy based on a detailed laboratory investigation. The investigation consists of Resonant Column (RC), Cyclic Torsional Shear (CTS), and Cyclic Triaxial (CTx) tests performed on 25 specimens of fine-grained soils retrieved from 11 sites in Sicily (South Italy). To develop accurate predictive models of soil dynamic properties, essential for site response analyses and dynamic soil-structure interaction, various regression techniques were applied. These techniques range from Multiple Linear Regression (MLR) to more complex AI methods, specifically Machine Learning (ML) and Deep Learning (DL) based on FeedForward Neural networks (FFN). Three predictive models were developed to derive strain-dependent shear modulus (<em>G</em>), damping ratio (<em>D</em>), and normalized shear modulus (<em>G</em>/<em>G</em><sub><em>0</em></sub>), using four inputs: shear strain (<em>γ)</em>, plasticity index (<em>PI)</em>, confining pressure (<em>p’</em><sub><em>0</em></sub>), and the Over Consolidation Ratio (OCR). To determine the optimal FFN topology, 1350 networks were developed by varying hidden layers (1–3), hidden neurons (1–50 per layer), and activation functions (ReLU, sigmoid and hyperbolic tangent). Hybrid FFN optimised through Genetic Algorithm and Particle Swarm Optimization techniques were also investigated. Single-hidden layer networks with fewer than 15 neurons provided acceptable predictions (<em>R</em><sup><em>2</em></sup><sub><em>test</em></sub> of 0.97 for <em>G</em>-<em>γ</em>, 0.93 for <em>G</em>/<em>G</em><sub><em>0</em></sub>-<em>γ</em>, and 0.85 for <em>D</em>-<em>γ</em> models). Multiple-hidden layer networks yielded higher accuracy for <em>G</em> and <em>D</em> models but are more complex for practical use. The FFN models outperformed MLR and other established empirical formulations, highlighting the site-specificity of the modelling parameters of the latter.</div></div>","PeriodicalId":49502,"journal":{"name":"Soil Dynamics and Earthquake Engineering","volume":"187 ","pages":"Article 109009"},"PeriodicalIF":4.2,"publicationDate":"2024-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142420090","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-10DOI: 10.1016/j.soildyn.2024.109018
Ye Liu , Yefei Ren , Ruizhi Wen , Hongwei Wang , Kun Ji , Yajun Zhang , Yingxin Hui
There has been extensive discussion as to whether the scope of site classification II is too broad in current Chinese seismic code. To address this issue, this study aims to optimize the site classification scheme for Chinese seismic code using clustering analysis of site amplification. Firstly, we estimate the empirical site amplification factors of KiK-net stations by the residual analysis method, and classify them by the site classification scheme of Chinese seismic code. Next, we perform k-means clustering analysis on the stations of site class II, considering site amplification factors, equivalent shear wave velocities and thicknesses of sedimentary layers as explanatory variables, and obtain two clusters with distinct site amplification effects. Finally, we use correlation analysis and Receiver Operating Characteristic (ROC) curve to guide the optimization of site classification scheme, and suggest dividing site class II into two subclasses, IIa and IIb, by a threshold of 15m for the thickness of sedimentary layer. The proposed optimized classification scheme would be beneficial for improving the seismic design code and could be further applied to the development of ground motion models and seismic hazard analysis.
关于现行中国地震规范中场地分类 II 的范围是否过于宽泛的问题已引起广泛讨论。针对这一问题，本研究旨在通过对台站放大系数的聚类分析，优化中国地震规范的台站分类方案。首先，利用残差分析方法估算 KiK 网台站的经验台址放大系数，并按照中国地震台网规范的台址分类方案进行分类。其次，以场址放大系数、等效剪切波速和沉积层厚度为解释变量，对Ⅱ类场址台站进行 K-均值聚类分析，得到两个场址放大效应不同的聚类。最后，利用相关性分析和接收者工作特征曲线（ROC）来指导站点分类方案的优化，并建议以沉积层厚度 15 米为临界值，将站点Ⅱ类分为Ⅱa 和Ⅱb 两个子类。建议的优化分类方案将有利于改进抗震设计规范，并可进一步应用于地震动模型的开发和地震危险性分析。
{"title":"An optimization suggestion for site classification scheme in Chinese seismic code based on clustering analysis of site amplification","authors":"Ye Liu , Yefei Ren , Ruizhi Wen , Hongwei Wang , Kun Ji , Yajun Zhang , Yingxin Hui","doi":"10.1016/j.soildyn.2024.109018","DOIUrl":"10.1016/j.soildyn.2024.109018","url":null,"abstract":"<div><div>There has been extensive discussion as to whether the scope of site classification II is too broad in current Chinese seismic code. To address this issue, this study aims to optimize the site classification scheme for Chinese seismic code using clustering analysis of site amplification. Firstly, we estimate the empirical site amplification factors of KiK-net stations by the residual analysis method, and classify them by the site classification scheme of Chinese seismic code. Next, we perform <em>k</em>-means clustering analysis on the stations of site class II, considering site amplification factors, equivalent shear wave velocities and thicknesses of sedimentary layers as explanatory variables, and obtain two clusters with distinct site amplification effects. Finally, we use correlation analysis and Receiver Operating Characteristic (ROC) curve to guide the optimization of site classification scheme, and suggest dividing site class II into two subclasses, II<sub>a</sub> and II<sub>b</sub>, by a threshold of 15m for the thickness of sedimentary layer. The proposed optimized classification scheme would be beneficial for improving the seismic design code and could be further applied to the development of ground motion models and seismic hazard analysis.</div></div>","PeriodicalId":49502,"journal":{"name":"Soil Dynamics and Earthquake Engineering","volume":"187 ","pages":"Article 109018"},"PeriodicalIF":4.2,"publicationDate":"2024-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142420081","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 : 2024-10-10DOI: 10.1016/j.soildyn.2024.109023
Jian-Cheng Dai , Dong-Sheng Wang , Wei-Jian Tang , Yu-He Zou , Ying-Xin Hui , Ya-Jun Zhang
The Probabilistic Seismic Demand Model (PSDM) is a crucial component of the performance-based seismic design framework when establishing the relationship between the ground motion intensity measure (IM) and the engineering demand parameter (EDP). The definitions of IMs and EDPs introduce varying degrees of uncertainty into the PSDM and notes different fragility or hazard analysis results. In accordance with the elastic limit state of the structural seismic response, this study normalizes two key parameters, the IM and EDP, within the PSDM. Normalized EDP (EDPN) is the ratio of the structural response to the elastic limit state of the structure, as defined by the onset of the strength yielding of the main structural element. Similarly, the IM (IMN) is normalized based on corresponding ground motions (scaled) that cause the structure to offer an elastic limit state response. This means that structural design strength is considered in IMN following the construction of a parameter-normalized PSDM. The study examined two typical isolated bridges presented their hazard curves with IMN. The results show that IMN can unify the efficiency and sufficiency of different IMs and reduce uncertainty in the PSDM. The assessment error of the structural elastic limit state for its design strength had little effect on the parameter-normalized PSDM, so the model is robust. Additionally, the IMN outperformed traditional IMs for efficiency and sufficiency in most instances.
{"title":"Parameter-normalized probabilistic seismic demand model considering the structural design strength for structural response assessment","authors":"Jian-Cheng Dai , Dong-Sheng Wang , Wei-Jian Tang , Yu-He Zou , Ying-Xin Hui , Ya-Jun Zhang","doi":"10.1016/j.soildyn.2024.109023","DOIUrl":"10.1016/j.soildyn.2024.109023","url":null,"abstract":"<div><div>The Probabilistic Seismic Demand Model (PSDM) is a crucial component of the performance-based seismic design framework when establishing the relationship between the ground motion intensity measure (IM) and the engineering demand parameter (EDP). The definitions of IMs and EDPs introduce varying degrees of uncertainty into the PSDM and notes different fragility or hazard analysis results. In accordance with the elastic limit state of the structural seismic response, this study normalizes two key parameters, the IM and EDP, within the PSDM. Normalized EDP (<em>EDP</em><sup>N</sup>) is the ratio of the structural response to the elastic limit state of the structure, as defined by the onset of the strength yielding of the main structural element. Similarly, the IM (<em>IM</em><sup>N</sup>) is normalized based on corresponding ground motions (scaled) that cause the structure to offer an elastic limit state response. This means that structural design strength is considered in <em>IM</em><sup>N</sup> following the construction of a parameter-normalized PSDM. The study examined two typical isolated bridges presented their hazard curves with <em>IM</em><sup>N</sup>. The results show that <em>IM</em><sup>N</sup> can unify the efficiency and sufficiency of different IMs and reduce uncertainty in the PSDM. The assessment error of the structural elastic limit state for its design strength had little effect on the parameter-normalized PSDM, so the model is robust. Additionally, the <em>IM</em><sup>N</sup> outperformed traditional IMs for efficiency and sufficiency in most instances.</div></div>","PeriodicalId":49502,"journal":{"name":"Soil Dynamics and Earthquake Engineering","volume":"187 ","pages":"Article 109023"},"PeriodicalIF":4.2,"publicationDate":"2024-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142420089","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}
As buried water reservoirs are increasingly being utilized to store and deliver water, they are now regarded as critical infrastructures that must continue to operate in the event of an earthquake. This paper presents the results of a large-scale numerical parametric study that was carried out to advance our understanding of the seismic fluid-structure-soil interaction (FSSI) response of buried water reservoirs. Advanced nonlinear three-dimensional (3D) FSSI numerical models of reservoirs were employed while considering reservoir size, embedment depth, soil profile, and ground motion variability. The study showed that, unlike other conventional underground structures, the peak ground acceleration (PGA) has the strongest correlation to the reservoir seismic response. Increasing the embedment depth or reservoir size was found to generally increase the demands on the structural elements while reducing the base and backfill slippage. Softer sites were found to cause an increase in the roof racking and including the vertical component of the motion increased the water dynamic pressures. Among the columns, the ones closest to the center were found to experience the highest demands and the ones at the corner the lowest. In fact, in some extreme cases, a total collapse of the reservoir was initiated by column failure due to the lack of structural redundancy. The roof in-plane shear stresses were observed to accumulate near the walls, indicating a diaphragm behavior. The reservoir's unique seismic response compared to other underground structures makes generalizing the commonly used simplified design procedures inapplicable. Instead, 3D FSSI numerical models were demonstrated to be a reliable tool for the seismic design of buried reservoirs.
{"title":"Seismic behavior of shallow buried water reservoirs via large scale three-dimensional numerical models","authors":"Karim AlKhatib , Youssef MA. Hashash , Katerina Ziotopoulou","doi":"10.1016/j.soildyn.2024.109005","DOIUrl":"10.1016/j.soildyn.2024.109005","url":null,"abstract":"<div><div>As buried water reservoirs are increasingly being utilized to store and deliver water, they are now regarded as critical infrastructures that must continue to operate in the event of an earthquake. This paper presents the results of a large-scale numerical parametric study that was carried out to advance our understanding of the seismic fluid-structure-soil interaction (FSSI) response of buried water reservoirs. Advanced nonlinear three-dimensional (3D) FSSI numerical models of reservoirs were employed while considering reservoir size, embedment depth, soil profile, and ground motion variability. The study showed that, unlike other conventional underground structures, the peak ground acceleration (PGA) has the strongest correlation to the reservoir seismic response. Increasing the embedment depth or reservoir size was found to generally increase the demands on the structural elements while reducing the base and backfill slippage. Softer sites were found to cause an increase in the roof racking and including the vertical component of the motion increased the water dynamic pressures. Among the columns, the ones closest to the center were found to experience the highest demands and the ones at the corner the lowest. In fact, in some extreme cases, a total collapse of the reservoir was initiated by column failure due to the lack of structural redundancy. The roof in-plane shear stresses were observed to accumulate near the walls, indicating a diaphragm behavior. The reservoir's unique seismic response compared to other underground structures makes generalizing the commonly used simplified design procedures inapplicable. Instead, 3D FSSI numerical models were demonstrated to be a reliable tool for the seismic design of buried reservoirs.</div></div>","PeriodicalId":49502,"journal":{"name":"Soil Dynamics and Earthquake Engineering","volume":"187 ","pages":"Article 109005"},"PeriodicalIF":4.2,"publicationDate":"2024-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142420088","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 : 2024-10-10DOI: 10.1016/j.soildyn.2024.109012
Denghui Dai , Kai Xue , Yufeng Gao , M. Hesham El Naggar , Xinyu Du , Ning Zhang
This paper presents an analytical solution for the axial kinematic response of an end-bearing pile under seismic P-wave excitation in a double-layered soil. The motions of the pile and adjacent soil layers are determined using the derived series solution. The seismic wave scattering effect caused by the combined action of the soil layers and pile foundations is accounted for. To validate the accuracy of the derived solution, the kinematic responses obtained from the proposed analytical solution are compared with the results from an existing solution for a pile in a single soil layer. The validated solution is then utilized to conduct a parametric study to investigate the impacts of the modulus and thickness ratios between the two soil layers on response characteristics. These characteristics include the kinematic response factor, amplification factor, frictional force exerted on the pile body, pile displacement with depth, and motion of soil around the pile.
本文给出了双层土中端承桩在地震 P 波激励下的轴向运动响应的分析解。利用推导出的序列解确定了桩和相邻土层的运动。其中考虑了土层和桩基的共同作用引起的地震波散射效应。为了验证推导解决方案的准确性，我们将根据建议的分析解决方案得到的运动响应与现有的单土层桩基解决方案的结果进行了比较。然后，利用验证后的解决方案进行参数研究，探讨两个土层之间的模量和厚度比对响应特性的影响。这些特征包括运动响应系数、放大系数、施加在桩身上的摩擦力、桩随深度的位移以及桩周围土壤的运动。
{"title":"Axial kinematic response of an end-bearing pile subjected to seismic P-wave excitation in a double-layered soil","authors":"Denghui Dai , Kai Xue , Yufeng Gao , M. Hesham El Naggar , Xinyu Du , Ning Zhang","doi":"10.1016/j.soildyn.2024.109012","DOIUrl":"10.1016/j.soildyn.2024.109012","url":null,"abstract":"<div><div>This paper presents an analytical solution for the axial kinematic response of an end-bearing pile under seismic P-wave excitation in a double-layered soil. The motions of the pile and adjacent soil layers are determined using the derived series solution. The seismic wave scattering effect caused by the combined action of the soil layers and pile foundations is accounted for. To validate the accuracy of the derived solution, the kinematic responses obtained from the proposed analytical solution are compared with the results from an existing solution for a pile in a single soil layer. The validated solution is then utilized to conduct a parametric study to investigate the impacts of the modulus and thickness ratios between the two soil layers on response characteristics. These characteristics include the kinematic response factor, amplification factor, frictional force exerted on the pile body, pile displacement with depth, and motion of soil around the pile.</div></div>","PeriodicalId":49502,"journal":{"name":"Soil Dynamics and Earthquake Engineering","volume":"187 ","pages":"Article 109012"},"PeriodicalIF":4.2,"publicationDate":"2024-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142420077","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}
This study addresses the urgent need for retrofitting masonry schools in Iran, where over 89 % of schools are constructed using masonry (107000 Schools consisted of 563000 classrooms). Focusing on seismic performance evaluation, this research is of paramount importance as the current state of these schools poses a significant risk to the safety of millions of students. Without proper evaluation, the consequences could be catastrophic. To illustrate the significance of this study, a confined masonry school in Tehran was selected as a representative case study. The seismic resilience index was calculated, considering two hazard levels (2 % and 10 %) over a 50-year period, with and without near-fault pulse-type ground motions. Furthermore, a comparative analysis was conducted by modeling the retrofitted structure, which involved the application of shotcrete on walls, to assess the benefits of retrofitting. The seismic resilience index, derived from analytical functions that account for probable hazards and the recovery process, serves as a comprehensive measure of the structure's vulnerability. Through this evaluation, valuable insights into the retrofitting and rehabilitation of confined masonry schools can be gained. The results obtained from this research will aid in informed decision-making regarding the mitigation of seismic risks in similar structures. In conclusion, this paper indicates applying shotcrete to masonry walls can be substantially efficient as the resilience index and functionality of the building increases by a significant margin. Furthermore, the building damage was halved after the retrofitting operation and fragility curves admit it by showing better performance in higher drift ratios.
{"title":"Seismic resilience evaluation of confined masonry school buildings retrofitted by shotcrete method","authors":"Ali Sadeghi Raveshti , Morteza Raissi Dehkordi , Mahdi Eghbali , Delbaz Samadian","doi":"10.1016/j.soildyn.2024.108980","DOIUrl":"10.1016/j.soildyn.2024.108980","url":null,"abstract":"<div><div>This study addresses the urgent need for retrofitting masonry schools in Iran, where over 89 % of schools are constructed using masonry (107000 Schools consisted of 563000 classrooms). Focusing on seismic performance evaluation, this research is of paramount importance as the current state of these schools poses a significant risk to the safety of millions of students. Without proper evaluation, the consequences could be catastrophic. To illustrate the significance of this study, a confined masonry school in Tehran was selected as a representative case study. The seismic resilience index was calculated, considering two hazard levels (2 % and 10 %) over a 50-year period, with and without near-fault pulse-type ground motions. Furthermore, a comparative analysis was conducted by modeling the retrofitted structure, which involved the application of shotcrete on walls, to assess the benefits of retrofitting. The seismic resilience index, derived from analytical functions that account for probable hazards and the recovery process, serves as a comprehensive measure of the structure's vulnerability. Through this evaluation, valuable insights into the retrofitting and rehabilitation of confined masonry schools can be gained. The results obtained from this research will aid in informed decision-making regarding the mitigation of seismic risks in similar structures. In conclusion, this paper indicates applying shotcrete to masonry walls can be substantially efficient as the resilience index and functionality of the building increases by a significant margin. Furthermore, the building damage was halved after the retrofitting operation and fragility curves admit it by showing better performance in higher drift ratios.</div></div>","PeriodicalId":49502,"journal":{"name":"Soil Dynamics and Earthquake Engineering","volume":"187 ","pages":"Article 108980"},"PeriodicalIF":4.2,"publicationDate":"2024-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142420079","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 : 2024-10-09DOI: 10.1016/j.soildyn.2024.109011
Fan Zhang , Yuguang Fu , Jingquan Wang
Earthquakes in recent decades have demonstrated that fault-crossing simply supported bridges were susceptible to damage caused by the fault-induced permanent ground dislocation. Cable restrainer can potentially reduce the relative displacement of bridge spans, but the current seismic design method for restrainer is time-consuming and labor-intensive. This study aims to develop a rapid and automated seismic design method for cable restrainer using explainable machine learning (ML) models. To do this, a large database was first generated based on the current design approach. ML algorithms were utilized to develop classification models to determine the design classes and then regression models to estimate the restrainer stiffness for the fault-crossing bridges. Furthermore, SHapley Additive exPlanations (SHAP) analysis was utilized to provide interpretations for the best regression model. In particular, an empirical formula and two explainable prediction models by combining the empirical formula with simplified ML models were finally proposed to facilitate the design for engineers. Results show that the proposed design method can provide accurate and robust results of bridge restrainers. Within the method, artificial neural network was selected among nine ML models, because of its highest accuracy for both classification and regression. The SHAP analysis reveals that, the allowable displacement has a negative nonlinear effect, while permanent ground dislocation and initial relative displacement present positive nonlinear effects. The proposed empirical formula for restrainer design can provide conservative estimations with an accuracy of 79 %, whereas the proposed explainable prediction models have a high accuracy of 94 % and are significantly efficient and user-friendly.
近几十年来发生的地震表明，跨越断层的简支桥梁很容易受到断层引起的永久地表位移的破坏。拉索约束装置有可能减少桥跨的相对位移，但目前的约束装置抗震设计方法耗时耗力。本研究旨在利用可解释的机器学习（ML）模型，开发一种快速、自动化的缆索约束抗震设计方法。为此，首先根据当前的设计方法生成了一个大型数据库。利用 ML 算法开发分类模型来确定设计类别，然后利用回归模型来估算跨断层桥梁的约束刚度。此外，还利用 SHapley Additive exPlanations（SHAP）分析法为最佳回归模型提供解释。特别是，通过将经验公式与简化的 ML 模型相结合，最终提出了一个经验公式和两个可解释的预测模型，以方便工程师进行设计。结果表明，所提出的设计方法可以为桥梁约束装置提供准确、稳健的结果。在该方法中，人工神经网络在分类和回归方面都具有最高的准确性，因此在九个 ML 模型中被选中。SHAP 分析表明，容许位移具有负非线性效应，而永久地面错位和初始相对位移则具有正非线性效应。所提出的约束装置设计经验公式可以提供保守的估计，准确率为 79%，而所提出的可解释预测模型的准确率高达 94%，并且非常高效和易于使用。
{"title":"Rapid and automated seismic design of cable restrainer for simply supported bridges crossing fault rupture zones using explainable machine learning","authors":"Fan Zhang , Yuguang Fu , Jingquan Wang","doi":"10.1016/j.soildyn.2024.109011","DOIUrl":"10.1016/j.soildyn.2024.109011","url":null,"abstract":"<div><div>Earthquakes in recent decades have demonstrated that fault-crossing simply supported bridges were susceptible to damage caused by the fault-induced permanent ground dislocation. Cable restrainer can potentially reduce the relative displacement of bridge spans, but the current seismic design method for restrainer is time-consuming and labor-intensive. This study aims to develop a rapid and automated seismic design method for cable restrainer using explainable machine learning (ML) models. To do this, a large database was first generated based on the current design approach. ML algorithms were utilized to develop classification models to determine the design classes and then regression models to estimate the restrainer stiffness for the fault-crossing bridges. Furthermore, SHapley Additive exPlanations (SHAP) analysis was utilized to provide interpretations for the best regression model. In particular, an empirical formula and two explainable prediction models by combining the empirical formula with simplified ML models were finally proposed to facilitate the design for engineers. Results show that the proposed design method can provide accurate and robust results of bridge restrainers. Within the method, artificial neural network was selected among nine ML models, because of its highest accuracy for both classification and regression. The SHAP analysis reveals that, the allowable displacement has a negative nonlinear effect, while permanent ground dislocation and initial relative displacement present positive nonlinear effects. The proposed empirical formula for restrainer design can provide conservative estimations with an accuracy of 79 %, whereas the proposed explainable prediction models have a high accuracy of 94 % and are significantly efficient and user-friendly.</div></div>","PeriodicalId":49502,"journal":{"name":"Soil Dynamics and Earthquake Engineering","volume":"187 ","pages":"Article 109011"},"PeriodicalIF":4.2,"publicationDate":"2024-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142420082","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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