Earthquake Engineering & Structural Dynamics最新文献

{"title":"Efficient seismic fragility analysis considering uncertainties in structural systems and ground motions","authors":"Jungho Kim,&nbsp;Taeyong Kim","doi":"10.1002/eqe.4254","DOIUrl":"https://doi.org/10.1002/eqe.4254","url":null,"abstract":"<p>Fragility plays a pivotal role in performance-based earthquake engineering, which represents the seismic performance of structural systems. To comprehensively understand the structural performance under seismic events, it is necessary to consider uncertainties in the structural model, i.e., epistemic uncertainties. However, considering such uncertainties is challenging due to computational complexity, leading most fragility analyses only to consider the chaotic behavior of ground motions on structural responses, i.e., aleatoric uncertainties. To address this challenge, this study proposes an adaptive algorithm that intertwines with the conventional fragility analysis procedures to consider both aleatoric and epistemic uncertainties. The algorithm introduces Gaussian process-based metamodels to efficiently consider epistemic uncertainties with a small number of time history analyses. Steel moment-resisting frame structures and a reinforced concrete building are used to demonstrate the improved efficiency and wide applicability of the proposed method. In each case, the proposed method yields fragility curves consistent with reference solutions but with substantially lower computational effort. Comprehensive discussions are provided regarding ground motion sets, structural types, and definitions of limit-states to demonstrate the robustness of the proposed approach.</p>","PeriodicalId":11390,"journal":{"name":"Earthquake Engineering & Structural Dynamics","volume":"54 1","pages":"206-226"},"PeriodicalIF":4.3,"publicationDate":"2024-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/eqe.4254","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142861380","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}

{"title":"The analytical curvature distribution model of columns and mathematical solution for pushover analysis","authors":"Jian Zhong,&nbsp;Yanyan Zhu,&nbsp;Hao Wang","doi":"10.1002/eqe.4245","DOIUrl":"https://doi.org/10.1002/eqe.4245","url":null,"abstract":"<p>The acquisition of a flexural backbone curve for columns primarily relies on finite element analysis and experiments, of which the complexity and high cost are significant challenges. Hence, this study proposes an analytical curvature distribution model (CDM) along the full height of the column, which is the key point of formula derivation and theoretical solution of the column backbone curve. The proposed CDM is a piecewise function model composed of linear and quadratic functions, with the characteristics of continuity and differentiability at the intersection point. The deformation compatibility equations, equilibrium equations, and material constitutive equations based on the variables of CDM are constructed to form an equation system, the solution of which can be theoretically determined by an iterative algorithm. Furthermore, 155 test specimen columns of different materials, for example, reinforced concrete, high-strength reinforced concrete, and shape memory alloy are used to validate the proposed CDM and mathematical solutions of pushover analysis through three crucial indicators, that is, goodness of fit of backbone curve, ultimate displacement, and peak force, indicating strong practicability, high accuracy, and wider applicability. This theoretical method can be applied to deal with the key issues of interest during pushover analysis, that is, predicting the flexural backbone curves with different materials, determining the curvature distribution throughout the entire process of pushover analysis, and characterizing the evolution process of the plastic region.</p>","PeriodicalId":11390,"journal":{"name":"Earthquake Engineering & Structural Dynamics","volume":"54 1","pages":"182-205"},"PeriodicalIF":4.3,"publicationDate":"2024-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142861382","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}

{"title":"In situ tests of building structures isolated by innovative three-dimensional vibration isolation bearings","authors":"Yingri Cao,&nbsp;Peng Pan,&nbsp;Zhizhou He,&nbsp;Jiangbo Sun,&nbsp;Jiangtao Wen,&nbsp;Gang Mao","doi":"10.1002/eqe.4250","DOIUrl":"https://doi.org/10.1002/eqe.4250","url":null,"abstract":"<p>An innovative three-dimensional vibration isolation bearing (3D-VIB) was proposed in past studies to mitigate rail-induced vibration and improve the seismic performance of buildings. The 3D-VIB was composed of a thick laminated rubber bearing as the vertical vibration isolation element and a friction pendulum system as the horizontal seismic isolation element. In this study, in situ tests were carried out on a subway over-track structure with 3D-VIBs. The in situ tests included the subway-induced vibration excitation test and the horizontal loading test on the same structure. In the subway-induced vibration excitation test, the vertical isolation performance of the test structure was changed by transforming the isolation layer from a normal vibration-isolation-state to a non-isolation-state. The comparison between the two states proved that the installation of 3D-VIBs significantly changed the vertical vibration mode and reduced the subway-induced vibration of the superstructure. The shear performances of the isolated structure were examined by the horizontal loading test, which subjected the superstructure to a large horizontal movement under external load. The shear performances of the structure with 3D-VIBs were consistent with that of the 3D-VIB specimens measured in the laboratory. The in situ tests confirmed the effectiveness and stability of the 3D-VIBs when applied to practical engineering.</p>","PeriodicalId":11390,"journal":{"name":"Earthquake Engineering & Structural Dynamics","volume":"54 1","pages":"146-163"},"PeriodicalIF":4.3,"publicationDate":"2024-10-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142860938","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}

{"title":"Seismic design and analysis of truss-confined buckling-restrained braces","authors":"An-Chien Wu,&nbsp;Keh-Chyuan Tsai,&nbsp;Chun Chen,&nbsp;Lu-An Chen,&nbsp;Ching-Yi Tsai","doi":"10.1002/eqe.4252","DOIUrl":"https://doi.org/10.1002/eqe.4252","url":null,"abstract":"<p>The truss-confined buckling-restrained brace (TC-BRB) with a varying or constant section truss confining system was proposed for applications of long span and large force capacities. Their feasibility and hysteresis behavior were examined through experimental investigations. This paper presents an original formulation of the elastic buckling resistance of the novel restraining system, considering the shear reduction effect. The findings indicate that the chord predominantly contributes to the flexural rigidity in the restraining system, while the post primarily contributes to the overall shear rigidity. Subsequently, the ultimate compressive strength of a TC-BRB is evaluated, incorporating the effects of chord residual stress, length differences between the restrainer and entire brace, and initial in-plane flexural deformation, based on available experimental data. A numerical procedure employing finite element model (FEM) analysis is introduced to simulate the mechanical characteristics of TC-BRBs. The critical loads are verified through FEM analyses and test results. The failure mode observed in the numerical models is the instability of the chords near the midspan, as expected. A simplified approach for determining the ultimate compressive strength and design recommendations for TC-BRBs are provided for engineering practice.</p>","PeriodicalId":11390,"journal":{"name":"Earthquake Engineering & Structural Dynamics","volume":"54 1","pages":"164-181"},"PeriodicalIF":4.3,"publicationDate":"2024-10-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142860939","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}

{"title":"Model- versus data-uncertainty for concrete members and connections in cyclic loading","authors":"Michael N. Fardis","doi":"10.1002/eqe.4251","DOIUrl":"https://doi.org/10.1002/eqe.4251","url":null,"abstract":"<p>Large databases of cyclic tests on flexure- or shear-critical concrete members and shear-critical connections of columns to beams or slabs are used to estimate the uncertainty inherent in experimental data in literature—as read by users. To this end, the predictions of two different, presumably independent, design-oriented models for the properties of interest are used to establish the “central tendency” of data, against which individual tests or small groups thereof are assessed. Properties considered are: (a) the cyclic ultimate chord-rotation of flexure-controlled members with continuous or lap-spliced deformed bars, (b) the cyclic shear strength of shear-critical members, (c) the chord-rotation at yielding of rectangular columns with plain bars, and (d) the cyclic shear strength of shear-controlled beam-column and slab-column joints. Results suggest that the data from each test campaign have a certain degree of bias, specific to it. Test campaigns with ratio of estimated average deviation from the “central tendency” to the standard deviation of campaign deviations (called “data uncertainty”) which is far into the tail of the Normal distribution may be excluded as questionable. This systematic bias, along with other types of “data uncertainty” addressed in this work, seem to contribute to the apparent scatter of model predictions with respect to cyclic test results the equivalent of a coefficient of variation of model-to-test-ratio of at least 10% and possibly as high as 25%–30%. Model uncertainty seems to contribute to this scatter the equivalent of a coefficient of variation of at least 15% in shear-controlled connections, or as much as 25% in the case of flexural deformation capacity of members with deformed bars; the cyclic shear resistance of members and—with the reservation of the small number of tests—the chord-rotation at yielding of members with plain bars, are in-between.</p>","PeriodicalId":11390,"journal":{"name":"Earthquake Engineering & Structural Dynamics","volume":"54 1","pages":"119-145"},"PeriodicalIF":4.3,"publicationDate":"2024-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/eqe.4251","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142860744","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}

{"title":"Test and sensitivity analysis of base-isolated steel frame with low-friction spherical sliding bearings","authors":"Motoki Akazawa,&nbsp;Masahiro Kurata,&nbsp;Shinsuke Yamazaki,&nbsp;Yohsuke Kawamata,&nbsp;Shintaro Matsuo","doi":"10.1002/eqe.4249","DOIUrl":"https://doi.org/10.1002/eqe.4249","url":null,"abstract":"<p>In Japan, spherical sliding bearings with low friction coefficients are gaining popularity for base-isolating low-rise frames that are relatively lightweight. However, the complete dataset of isolators and a base-isolated frame for evaluating the model sensitivity and response uncertainty are limited. This study first presents the design process, isolation unit- and frame-level testing, and a blind prediction contest conducted on the occasion of full-scale shaking table testing of a three-story base-isolated hospital specimen. The design process utilizes a numerical model that accounts for the velocity and contact pressure dependencies and requires soft- and hard-case simulations with nominal friction coefficients plus and minus standard deviation to consider the uncertainties associated with the bearing behavior. The pre-shipment isolation unit and frame shake table testing yielded an invaluable dataset for bearings under normal and low contact pressures, low and high velocities, and constant and varying axial loads. The accompanying blind prediction contest provided a valuable dataset for rethinking the impact of modeling uncertainty. In-depth data analysis and sensitivity analysis were conducted. The sliding coefficient increased under low-contact pressure and low-velocity conditions. The static friction coefficient was 1.9 to 4.5 times higher than the dynamic coefficient, but this had little impact on the residual displacement, cumulative travel, and maximum story shear force. The axial force fluctuation, vertical motion, and two-directional input did not significantly affect the bearing behavior in the test. The test and the following simulations confirmed that the low friction coefficient helped the building contents, that is, medical equipment in this study, remain in order under near-fault and long-period ground motions.</p>","PeriodicalId":11390,"journal":{"name":"Earthquake Engineering & Structural Dynamics","volume":"54 1","pages":"100-118"},"PeriodicalIF":4.3,"publicationDate":"2024-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/eqe.4249","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142860743","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}

{"title":"SSI-induced seismic earth pressures on an integral abutment bridge model: Experimental measurements versus numerical simulations and code provisions","authors":"Gabriele Fiorentino,&nbsp;Raffaele De Risi,&nbsp;Flavia De Luca,&nbsp;George Mylonakis,&nbsp;Bruno Briseghella,&nbsp;Camillo Nuti,&nbsp;Anastasios Sextos","doi":"10.1002/eqe.4237","DOIUrl":"https://doi.org/10.1002/eqe.4237","url":null,"abstract":"<p>Integral abutment bridges (IABs) generate strong soil–structure interaction (SSI) effects due to their high structural stiffness and transmission of inertial and thermal loads generated at the deck directly to the abutments. Despite an increasing number of experimental and numerical studies available in the literature, there is a lack of consolidated methodologies to model dynamic SSI phenomena for IABs, particularly in seismic regions where uncertainties associated with the induced ground motions render the problem harder to tackle. This study proposes an advanced strategy to model the seismic response of IABs, accounting for dynamic interaction between the structure, the abutment and the foundation, including piles and earth retaining walls. To this end, detailed finite-element studies were carried out employing OpenSees to simulate a recent experimental campaign on a scaled IAB model in a soil container (SERENA) carried out at EQUALS Lab, University of Bristol, in the framework of SERA/H2020 project. An extensive dataset in terms of recorded accelerations, displacements, strains and settlements are available from these tests, including earth pressures which are back-calculated from bending strain measurements. The objectives of this paper are threefold: firstly, the model parameters are explored and assessed critically by comparing the results from the numerical simulations against the experimental data; secondly, once the model is deemed sufficiently representative of the experiments, earth pressures are obtained numerically, as these are not directly measured in the tests; thirdly, the estimated static and dynamic earth pressures on the abutment wall are compared with the predictions of two simplified analytical procedures currently under consideration for inclusion in the new Eurocode 8. The results indicate that records and predictions match well for frequencies of up to 40 Hz at model scale (about 8 Hz in prototype scale) and confirm that the proposed modelling strategy can be used in practical applications. The quasi-elastic model proposed in this study is shown to provide dependable predictions for cases involving moderate strains in real-life applications.</p>","PeriodicalId":11390,"journal":{"name":"Earthquake Engineering & Structural Dynamics","volume":"53 15","pages":"4830-4852"},"PeriodicalIF":4.3,"publicationDate":"2024-10-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/eqe.4237","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142579761","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}

{"title":"Experimentally-based in-plane drift limits for the upper threshold of masonry light damage","authors":"Paul A. Korswagen,&nbsp;Jan G. Rots,&nbsp;Karel C. Terwel","doi":"10.1002/eqe.4246","DOIUrl":"https://doi.org/10.1002/eqe.4246","url":null,"abstract":"<p>Drift limits are useful thresholds; during design or retrofitting analyses, engineers can compare the expected behaviour of a structure to drift limits that predict when the structure will reach a certain condition. This helps ensure that structures satisfy specified performance goals when exposed to certain hazards. Masonry walls are susceptible to damage from lateral in-plane actions such as wind or earthquake loading; ensuring that in-plane drift remains sufficiently small will help limit this damage. Drift limits based on crack-based damage are scarce, however, with DS1 limits being extrapolated from higher damage grades based on structural strength capacity or ductility. In this work, crack-based damage is evaluated on a multitude of full-scale experimental walls surveyed with digital image correlation. This method observes the initiation and propagation of cracking. Cyclically incremental in-plane tests provide a range of drift-damage relationships. These are explored with machine learning to determine influential predictors and ultimately establish drift limits for light damage. Two types of brick masonry are explored: fired-clay and calcium-silicate. For the latter, light damage begins at an in-plane drift of 0.5 mm/m and can extend to 4.8 mm/m (or 0.48%) for the former before the masonry surpasses light damage and reaches structural damage grades. In comparison to drift limits set by other authors and (international) guidelines to characterise light damage, significant damage, or the ultimate capacity of masonry walls, the resulting drift limits for light damage from this work are set directly on the basis of experiments and are in good agreement with other authors. Most importantly, all the consulted values for ultimate capacity are much larger than the upper threshold for light damage determined herein, with limits for significant damage in the same order of magnitude. This result verifies the accuracy of the experimental crack-based characterisation used to establish the drift thresholds.</p>","PeriodicalId":11390,"journal":{"name":"Earthquake Engineering & Structural Dynamics","volume":"54 1","pages":"86-99"},"PeriodicalIF":4.3,"publicationDate":"2024-10-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/eqe.4246","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142860281","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}

{"title":"Local and global integrative retrofitting of reinforced concrete frames using in-plane buckling steel braces","authors":"Devyani Tewatia,&nbsp;P. C. Ashwin Kumar","doi":"10.1002/eqe.4247","DOIUrl":"https://doi.org/10.1002/eqe.4247","url":null,"abstract":"<p>Two large-scale, single-storey, single-bay reinforced concrete (RC) moment frames, designed as per an outdated seismic code to represent a typical framing detail of a four-storey building, have been tested under displacement-controlled quasi-static loading protocol as per ACI 374.1-05. The RC frames include a plinth beam with brick infill underneath, a slab monolithically cast with the top beam and provision for applying axial load to the column to simulate real construction scenario. One of the frames has been tested as a bare frame, and the second one has been retrofitted with conventional steel braces designed to undergo in-plane buckling. The size of the brace has been selected based on the result of a nonlinear time history analysis of representative low- to mid-rise open-ground storey RC buildings. Post-installed chemical anchors have been utilized to connect the steel braces to the narrow RC frame members following the outcomes of an experimental investigation by the same authors. Local-level retrofitting by steel jacketing using adhesives has been designed and utilized on columns and beams to achieve the desired seismic response. The seismic performance of the retrofitted frame has been compared with the bare frame in terms of strength, stiffness, ductility, energy dissipation and hysteretic damping. The tests provide insight into the role of the plinth beam, effect of RC slab on the strong-column weak-beam aspect and the achievement of the desirable hinge mechanism through a precise design and detailing of global and local level retrofitting technique.</p>","PeriodicalId":11390,"journal":{"name":"Earthquake Engineering & Structural Dynamics","volume":"54 1","pages":"5-31"},"PeriodicalIF":4.3,"publicationDate":"2024-10-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142860277","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}

{"title":"Random-positioned-sampling effect on probabilistic seismic demand modeling of modularized suspended buildings with free-standing objects and architectural function regioning","authors":"Zhihang Ye,&nbsp;Xuanting Liu","doi":"10.1002/eqe.4241","DOIUrl":"https://doi.org/10.1002/eqe.4241","url":null,"abstract":"<p>The definition of the targeted engineering demand parameters (EDPs) is important to probabilistic seismic demand modeling (PSDM), which produces probability density functions of EDPs conditioned on seismic intensity measure (IM). The targeted EDPs are usually defined at the group level to account for multiple components/units. Thus, they are affected by the considered range of units, i.e., the sample positions. For instance, the maximum peak floor acceleration (PFA) within the whole building differs from the maximum among only the important positions related to seismic loss. Additional uncertainties are induced in the PSDM of PFA if the sample positions vary when architectural function and non-structural elements change. In this study, the aforementioned influence is termed random-positioned-sampling (RPS) effect, and it is investigated by targeting a modularized suspended building, which features the tuning mechanism, multiple major modes, uneven response envelopes, and notable non-structural-object-structure interactions (NSOSI). Results show that the RPS effect lowers the maximum-based group-level EDP and increases the dispersion within the EDP sample sets, indicating that conventional PSDMs without considering the RPS effect are biased. The significance of the influence is positively correlated to the position-wise coefficient of variation of EDP but negatively correlated to the density of sample positions. The combined influence of the NSOSI and the RPS effect is two-sided for PSDM. The NSOSI amplifies the RPS effect via enlarging position-wise dispersion of EDP, whereas, the RPS effect waives part of the detrimental scattered contributions from NSOSI. Overall, the IM performance is handicapped, even with IM optimization. However, it can be compensated if architectural function region information is acquired beforehand since the sample positions are restrained.</p>","PeriodicalId":11390,"journal":{"name":"Earthquake Engineering & Structural Dynamics","volume":"54 1","pages":"32-61"},"PeriodicalIF":4.3,"publicationDate":"2024-10-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142860278","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}