Engineering Structures最新文献

Effect of ICCP on conductivity properties of carbon fiber bundles and CFRCM ICCP 对碳纤维束和 CFRCM 传导性能的影响

IF 5.6 1区工程技术 Q1 ENGINEERING, CIVIL

Engineering Structures

Pub Date : 2024-11-16 DOI: 10.1016/j.engstruct.2024.119311

Jiaxin Hong, Dawei Zhang, Yewangzhi Tao, Jiarong Liu

The effectiveness of carbon fabric reinforced cementitious matrix (CFRCM) in impressed current cathodic protection (ICCP) and structural strengthening (SS) of reinforced concrete (RC) structures has been verified. Meanwhile, due to the piezoresistive effect of carbon fibers, CFRCM has been developed as a self-monitoring sensor for structural health monitoring (SHM). However, the conductivity properties of CFRCM and carbon fiber under ICCP will be subject to performance degradation due to anodic reaction, which may have adverse effects on their role in SHM, and the degradation in seawater sea-sand (chlorine-containing environments) is still unknown. In this study, simulated ICCP tests were carried out on carbon fiber bundles in different solution environments and mortar environments to investigate the influences and mechanisms of different ICCP current densities, electrification durations, electrification environments, fiber lengths, and mortar types on conductivity properties of carbon fiber bundles and CFRCM. The prediction models for resistance were established based on a large number of experimental measurements. The results show that changes in resistance of carbon fiber bundles and CFRCM under ICCP exhibit two-stage characteristics of linear growth and rapid growth. The presence of chloride ions in seawater sea-sand environments can share polarization currents, reduce electrode potential, and slow down carbon fiber degradation. The degradation rates of carbon fiber bundles under four electrification environments, from fast to slow, are as follows: normal mortar, seawater sea-sand mortar, saturated Ca(OH)₂ solution, and saturated Ca(OH)₂ solution prepared with seawater. This study aims to promote the development of CFRCM materials with the multifunctional properties of ICCP-SS and SHM, and to achieve rational utilization of seawater and sea-sand.

碳纤维增强水泥基质（CFRCM）在钢筋混凝土（RC）结构的阴极保护（ICCP）和结构加固（SS）中的有效性已得到验证。同时，由于碳纤维的压阻效应，CFRCM 已被开发为结构健康监测（SHM）的自监测传感器。然而，在 ICCP 条件下，CFRCM 和碳纤维的导电性能会因阳极反应而发生性能退化，这可能会对其在 SHM 中的作用产生不利影响，而且在海水海砂（含氯环境）中的退化情况尚不清楚。本研究对不同溶液环境和砂浆环境下的碳纤维束进行了模拟 ICCP 试验，以研究不同 ICCP 电流密度、通电持续时间、通电环境、纤维长度和砂浆类型对碳纤维束和 CFRCM 传导性能的影响和机制。根据大量实验测量结果建立了电阻预测模型。结果表明，碳纤维束和 CFRCM 在 ICCP 条件下的电阻变化呈现线性增长和快速增长两个阶段的特征。海水海沙环境中氯离子的存在可以分担极化电流，降低电极电位，减缓碳纤维降解速度。碳纤维束在普通砂浆、海水海砂砂浆、饱和 Ca(OH)2 溶液、海水制备的饱和 Ca(OH)2 溶液四种电化环境下的降解速率由快到慢依次为：普通砂浆、海水海砂砂浆、饱和 Ca(OH)2 溶液、海水制备的饱和 Ca(OH)2 溶液。本研究旨在促进具有 ICCP-SS 和 SHM 多功能特性的 CFRCM 材料的发展，并实现海水和海砂的合理利用。

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引用次数: 0

Comparison study of seismic-tsunami performance for coastal bridges with different RC sacrificial shear keys 采用不同钢筋混凝土牺牲剪力键的沿海桥梁抗震-海啸性能对比研究

IF 5.6 1区工程技术 Q1 ENGINEERING, CIVIL

Engineering Structures

Pub Date : 2024-11-16 DOI: 10.1016/j.engstruct.2024.119295

Heng Mei , Anxin Guo

Simple-support bridges are employed in offshore regions as integral component of coastal transportation networks. However, these bridges are vulnerable to the combined effects of earthquakes and ensuing tsunami waves due to weak lateral resistance. Reinforced concrete (RC) shear keys have been widely utilized to strengthen bridges by providing extra constraints to the superstructure. While the seismic performance of RC shear keys has been extensively studied, their effectiveness under the sequential action of both hazards remains seldom addressed yet. Therefore, this study aims to compare the seismic-tsunami response of bridges with different RC shear keys. To this regard, a novel envelope curve model was developed for the diagonal failure shear key, with emphasis on their distinct behaviors under seismic and tsunami impacts. OpenSees platform was employed, with natural ground motions and second-order solitary wave theory adopted for seismic and tsunami modeling, respectively. The shear key under each hazard was simulated using an Update Material approach to account for the distinct mechanical property. Subsequently, a parametric study was carried out to compare various factors, including shear key failure modes and strength, as well as wave conditions. The analysis result showed that the maximum strength of RC shear keys can significantly affect bridge performance, while the failure mode also contributes. In addition, the wave condition can largely affect the time-history and maximum deformation depending on water depths. Furthermore, the recommendations for shear key design against sequential seismic-tsunami hazards were provided.

近海地区采用简支桥梁作为沿海交通网络的组成部分。然而，由于侧向阻力较弱，这些桥梁很容易受到地震和随之而来的海啸波的共同影响。钢筋混凝土（RC）剪力键已被广泛用于加固桥梁，为上部结构提供额外的约束。虽然对钢筋混凝土剪力键的抗震性能进行了广泛研究，但其在两种灾害的连续作用下的有效性仍鲜有涉及。因此，本研究旨在比较采用不同 RC 剪力键的桥梁的地震-海啸响应。为此，针对对角线破坏剪力键开发了一种新的包络曲线模型，重点研究它们在地震和海啸冲击下的不同行为。研究采用了 OpenSees 平台，地震和海啸模型分别采用了自然地面运动和二阶孤波理论。采用更新材料方法模拟了每种灾害下的剪切键，以考虑不同的力学性能。随后，进行了参数研究，以比较各种因素，包括剪力键失效模式和强度以及波浪条件。分析结果表明，RC 剪力键的最大强度会对桥梁性能产生重大影响，同时失效模式也会对桥梁性能产生影响。此外，波浪条件会在很大程度上影响时间历程和最大变形，具体取决于水深。此外，还提供了针对地震-海啸连续灾害的剪力键设计建议。

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引用次数: 0

Flexural behavior of reinforced concrete beams at low temperatures 低温条件下钢筋混凝土梁的抗弯行为

IF 5.6 1区工程技术 Q1 ENGINEERING, CIVIL

Engineering Structures

Pub Date : 2024-11-16 DOI: 10.1016/j.engstruct.2024.119263

Gu Xiang-Lin , Wu Jie-Ying , Yu Qian-Qian , Liu Shuang , Huang Qing-Hua

This paper performs a comprehensive study on the flexural behavior of reinforced concrete (RC) beams at temperatures ranging from −180 ℃ to 20 ℃. Mechanical properties of steel reinforcements and concrete at low temperatures were first analyzed by tensile tests and uniaxial compressive tests, respectively. Empirical formulae for the mechanical properties of reinforcements and concrete at low temperatures were developed. Subsequently, four-point bending tests were conducted to investigate the bending capacities of RC beams (40 × 40 × 300 mm) at temperatures of 20 ℃, −40 ℃, −80 ℃, −120 ℃, −160 ℃, and −180 ℃. A finite element (FE) model of the RC beams at low temperatures was also established and verified by comparing with the test results. Based on the validated model, a parametric analysis was performed on full-scale RC beams, in consideration with the parameters of reinforcement ratio, compressive strengths of concrete, and the height of a beam. Finally, an analytical model was proposed for the bending capacity of an RC beam at temperatures from −180 ℃ to 20 ℃. Results showed that due to the increased yield strength of reinforcement and compressive strength of concrete, the yield strength and ultimate strength of an RC beam were also obviously increased at low temperatures. As the temperature decreased from 20 ℃ to −40 ℃, −80 ℃, −120 ℃, −160 ℃ and −180 ℃, the ultimate strength of an RC beam was increased by 26.5%, 39.4%, 91.5%, 112.3% and 160.6%, respectively.

本文对钢筋混凝土（RC）梁在 -180 ℃ 至 20 ℃ 温度范围内的抗弯行为进行了全面研究。首先分别通过拉伸试验和单轴抗压试验分析了钢筋和混凝土在低温下的力学性能。建立了低温下钢筋和混凝土力学性能的经验公式。随后，进行了四点弯曲试验，以研究 RC 梁（40 × 40 × 300 毫米）在 20 ℃、-40 ℃、-80 ℃、-120 ℃、-160 ℃ 和-180 ℃ 温度下的抗弯强度。此外，还建立了低温下 RC 梁的有限元（FE）模型，并通过与测试结果进行比较进行了验证。在验证模型的基础上，考虑到配筋率、混凝土抗压强度和梁高等参数，对全尺寸 RC 梁进行了参数分析。最后，提出了在 -180 ℃ 至 20 ℃ 温度条件下 RC 梁抗弯能力的分析模型。结果表明，由于钢筋屈服强度和混凝土抗压强度的提高，低温下 RC 梁的屈服强度和极限强度也明显提高。当温度从 20 ℃ 降到 -40℃、-80℃、-120℃、-160℃ 和 -180 ℃ 时，RC 梁的极限强度分别提高了 26.5%、39.4%、91.5%、112.3% 和 160.6%。

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引用次数: 0

Impact resistance characteristics of pipeline system covered with W-shape elastic-porous metallic damper 覆有 W 型弹性多孔金属阻尼器的管道系统的抗冲击特性

IF 5.6 1区工程技术 Q1 ENGINEERING, CIVIL

Engineering Structures

Pub Date : 2024-11-15 DOI: 10.1016/j.engstruct.2024.119302

Xin Xue, Shaoxiang Ge, Yilin Chen, Yuhan Wei, Juan Liao

As a novel elastic-porous damping material fabricated through entangled wire mesh, W-shape elastic-porous metallic damper (W-EPMD) is considered an ideal damping element for coated pipeline system due to the micro dry friction between metal wires, which induces energy dissipation. The complex interwoven cellular formations of metallic wire mesh pose challenges in characterizing its dynamic characteristics. In this work, the dynamic properties of the pipeline system covered with W-EPMD under various impact conditions, including the acceleration response and impact isolation coefficient, were investigated by numerical simulations and experimental analysis. Constitutive models used to characterize the hysteresis behavior of W-EPMD were introduced, comprising Yeoh and Bergström-Boyce models, and parameter identification were conducted through quasi-static experiments. The reliability of the established numerical model was confirmed through drop impact experiments. The results demonstrate that there is a maximum discrepancy of 9.1 % between the simulation predictions and experimental results of the stress-strain curve. The impact isolation coefficient of the pipeline system covered with W-EPMD exhibits a fluctuating trend with the rise of the pulse peak, while the maximum compression of W-EPMD steadily increases. During the pipeline impact process, the increased density of W-EPMD reduces the impact resistance of the pipeline system, while excessively low density leads to over-compression and structural damage to W-EPMD. Furthermore, the discrepancy of the acceleration response between experimental and numerical results under various excitation signals remain within 6 %, demonstrating that the hysteresis model effectively characterizes the impact resistance characteristics of the pipeline system covered the W-EPMD.

作为一种通过缠结金属丝网制成的新型弹性多孔阻尼材料，W 型弹性多孔金属阻尼器（W-EPMD）被认为是涂层管道系统的理想阻尼元件，因为金属丝网之间的微干摩擦会导致能量耗散。金属丝网复杂的交织蜂窝状结构为表征其动态特性带来了挑战。在这项工作中，通过数值模拟和实验分析，研究了在各种冲击条件下包覆 W-EPMD 的管道系统的动态特性，包括加速度响应和冲击隔离系数。介绍了用于描述 W-EPMD 滞后行为的构成模型，包括 Yeoh 模型和 Bergström-Boyce 模型，并通过准静态实验进行了参数识别。通过落锤冲击实验证实了所建立的数值模型的可靠性。结果表明，应力-应变曲线的模拟预测值与实验结果之间的最大差异为 9.1%。覆盖有 W-EPMD 的管道系统的冲击隔离系数随着脉冲峰值的升高呈波动趋势，而 W-EPMD 的最大压缩量则稳步增加。在管道冲击过程中，W-EPMD 密度的增加会降低管道系统的抗冲击能力，而密度过低则会导致 W-EPMD 压缩过度和结构损坏。此外，在各种激励信号下，实验结果与数值结果之间的加速度响应差异保持在 6% 以内，表明滞后模型有效地描述了覆盖 W-EPMD 的管道系统的抗冲击特性。

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引用次数: 0

Dynamic sensitive failure mode in the progressive collapse of RC structures subjected to column removal scenarios 受支柱拆除影响的钢筋混凝土结构逐步倒塌过程中的动态敏感破坏模式

IF 5.6 1区工程技术 Q1 ENGINEERING, CIVIL

Engineering Structures

Pub Date : 2024-11-15 DOI: 10.1016/j.engstruct.2024.119301

Luchuan Ding , Jianbing Chen , Robby Caspeele

A series of structural collapse failures over the last decades have triggered an increasing research interest to identify ways to prevent progressive collapse when structures are subjected to local damage due to foreseen or unforeseen actions. Strong nonlinearities, dynamic effects, and system behavior should be taken into account in progressive collapse analyses. In order to avoid time-consuming nonlinear dynamic analyses, approaches using a dynamic increase factor or the energy-based method to the static pushdown curve are widely adopted. However, in this article it is shown that reinforce concrete (RC) structures may be evaluated as safe according to a static analysis but essentially unsafe when considering a dynamic analysis due to the dynamic snap-through behavior. This phenomenon results in a dynamic sensitive failure mode (DSFM) that should be identified in relation to progressive collapse analyses. Comparing with the static situation, the dynamic instability may result in a much more brittle failure mode in the dynamic situation due to the dynamic effects. Hence, the structure becomes sensitive to the dynamic effects and this may further lead to danger of brittle failure, which should be prevented in practice. An efficient method is proposed to approximately determine the load-displacement region where the DSFM occurs. This region is designated as the DSFM window. A two-linear-spring system, a RC beam-column substructure, and a RC frame structure are employed to illustrate the DSFM and verify the proposed method. The results demonstrate that the proposed approach can effectively determine the DSFM window for RC structures subjected to column removal scenarios.

过去几十年间发生的一系列结构坍塌事故，引发了人们对如何防止结构在可预见或不可预见的作用下受到局部破坏时发生渐进式坍塌的日益浓厚的研究兴趣。在渐进式坍塌分析中，应考虑到强烈的非线性、动态效应和系统行为。为了避免耗时的非线性动态分析，使用动态增加系数或基于能量的静态下压曲线的方法被广泛采用。然而，本文指出，钢筋混凝土（RC）结构在静态分析中可能被评估为安全的，但在考虑动态分析时，由于其动态快速通过行为，本质上是不安全的。这种现象导致了动态敏感失效模式 (DSFM)，应在渐进式坍塌分析中加以识别。与静态情况相比，在动态情况下，由于动态效应，动态不稳定性可能会导致更脆的破坏模式。因此，结构对动态效应变得敏感，这可能会进一步导致脆性破坏的危险，在实践中应加以防止。本文提出了一种有效的方法来近似确定发生 DSFM 的载荷-位移区域。该区域被称为 DSFM 窗口。采用双线性弹簧系统、RC 梁柱下部结构和 RC 框架结构来说明 DSFM 并验证所提出的方法。结果表明，所提出的方法可以有效地确定柱拆除情况下 RC 结构的 DSFM 窗口。

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引用次数: 0

Strengthening, lifetime extension, and monitoring of a deficient steel–concrete composite roadway bridge using iron-based shape memory alloys 使用铁基形状记忆合金加固、延长使用寿命并监测有缺陷的钢-混凝土复合材料公路桥梁

IF 5.6 1区工程技术 Q1 ENGINEERING, CIVIL

Engineering Structures

Pub Date : 2024-11-15 DOI: 10.1016/j.engstruct.2024.119286

Jakub Vůjtěch , Pavel Ryjáček , Hessamoddin Moshayedi , Jose Campos Matos , Elyas Ghafoori

This study presents an innovative application of smart metals for the prestressed strengthening of roadway bridges. The target structure is a steel–concrete composite bridge, in which poor construction practices cause nonlinear creep, excessive deflection, and crack growth. However, the high flood water level of the creek below the bridge limits the application of conventional strengthening solutions. Therefore, an innovative strengthening method using iron-based shape memory alloy (Fe-SMA) bars for the post-tensioning of bridge members was designed and employed. The study framework encompassed the design, laboratory examination, installation, and monitoring of Fe-SMA reinforcements. A finite-element simulation was used to estimate the effect of applied prestressing on the stress distribution of the structure. High-cycle fatigue tests of Fe-SMA bars with different types of connections at room temperature and –20 °C, were conducted to select the most reliable connections. A total of approximately 825 m of Fe-SMA bars with a diameter of 18 mm, comprising 68 Fe-SMA bars, were installed and activated. A wireless sensor monitoring system consisting of strain gauges, potentiometers, linear-variable differential transformer sensors, and thermocouples was utilized to measure the changes in strain and stress of the designed system under field conditions. The results revealed a prestress loss of 8.5 % owing to relaxation after six months, which match well to the values obtained by the laboratory tests. A second static loading test was conducted approximately six months after strengthening, and the results indicated a 9 % reduction in mid-span deflection and a remarkable 106 % reduction in average stresses in the lower flange at the mid-span of the beams. The results of monitoring the bridge for a duration longer than 6 months highlighted a significant decrease in the mid-span deflection and indicated the potential of Fe-SMAs for the lifetime extension of bridges.

本研究介绍了智能金属在公路桥梁预应力加固中的创新应用。目标结构是一座钢-混凝土复合结构桥梁，其中不良的施工方法会导致非线性蠕变、过大的挠度和裂缝增长。然而，桥下小溪的洪水位较高，限制了传统加固方案的应用。因此，我们设计并采用了一种创新的加固方法，使用铁基形状记忆合金（Fe-SMA）杆件对桥梁构件进行后张拉加固。研究框架包括 Fe-SMA 加固材料的设计、实验室检查、安装和监控。采用有限元模拟估算了施加预应力对结构应力分布的影响。在室温和零下 20 °C的条件下，对采用不同连接方式的 Fe-SMA 钢筋进行了高循环疲劳试验，以选出最可靠的连接方式。共安装并激活了约 825 米直径为 18 毫米的 Fe-SMA 杆件，其中包括 68 根 Fe-SMA 杆件。由应变计、电位计、线性可变差动变压器传感器和热电偶组成的无线传感器监测系统用于测量设计系统在现场条件下的应变和应力变化。结果显示，6 个月后由于松弛造成的预应力损失为 8.5%，与实验室测试得出的数值完全吻合。在加固约六个月后进行了第二次静态加载试验，结果表明跨中挠度减少了 9%，梁跨中下翼缘的平均应力显著减少了 106%。对桥梁进行超过 6 个月的监测结果表明，中跨挠度显著减小，这表明铁-SMA 具有延长桥梁使用寿命的潜力。

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引用次数: 0

A cable-based tuned inerter damper for edgewise vibration control of the wind turbine blade 用于风力涡轮机叶片边缘振动控制的缆式调谐插入式阻尼器

IF 5.6 1区工程技术 Q1 ENGINEERING, CIVIL

Engineering Structures

Pub Date : 2024-11-14 DOI: 10.1016/j.engstruct.2024.119248

Jiawei Tang , Qinlin Cai , Kaoshan Dai , Yangzhao Liu , Junling Heng , Yuxiao Luo

As wind turbines grow larger, with longer blades aimed at enhancing wind energy conversion efficiency, the accompanying increase also results in heightened vibration, thereby posing safety challenges to the structure. The cable-based method, requiring limited stroke and installation space while ensuring satisfactory control performance, is an emerging vibration control strategy in these structures. This study evaluates the efficacy of a wind blade-suited cable-based tuned inerter damper (CTID) in mitigating edgewise vibrations. The CTID comprises inerter, damping, and spring elements, anchored at the hub and connected to the blade tip through a cable. First, the multi-degree-of-freedom blade-CTID coupled model is established. Subsequently, the wind load spectrum of the rotating blade is derived by considering the rotational Fourier spectrum of wind speeds acting on the blade. The pseudo excitation method facilitates stochastic response analysis under wind loads, while particle swarm optimization identifies optimal CTID parameters. The effectiveness of the CTID is numerically validated through a comparison with the conventional tuned mass damper, demonstrating its superior vibration mitigation performance and less on-demand stroke. The associated practical issues of the CTID are discussed, such as the axial cable force-induced instability and buckling issues. The numerical results of this study proved the effectiveness and practicability of rotating blade-suited CTID, providing a novel and promising vibration control strategy in limited-space structures.

随着风力涡轮机越来越大，叶片越来越长，旨在提高风能转换效率，随之而来的是振动加剧，从而给结构带来安全挑战。基于电缆的方法需要有限的行程和安装空间，同时又能确保令人满意的控制性能，是这些结构中一种新兴的振动控制策略。本研究评估了适合风叶的缆索式可调阻尼器（CTID）在减轻边缘振动方面的功效。CTID 由阻尼器、阻尼和弹簧元件组成，固定在轮毂上，并通过电缆连接到叶片尖端。首先，建立多自由度叶片-CTID 耦合模型。随后，通过考虑作用在叶片上的风速的旋转傅里叶频谱，得出旋转叶片的风载荷谱。伪激励法有助于风载荷下的随机响应分析，而粒子群优化法可确定 CTID 的最佳参数。通过与传统的调谐质量阻尼器进行比较，对 CTID 的有效性进行了数值验证，证明其具有卓越的减振性能，并减少了按需行程。研究还讨论了 CTID 的相关实际问题，如轴向拉索力引起的不稳定性和屈曲问题。这项研究的数值结果证明了适合旋转叶片的 CTID 的有效性和实用性，为有限空间结构提供了一种新颖且有前途的振动控制策略。

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引用次数: 0

Reference-free distributed monitoring of deflections in multi-span bridges 多跨桥梁挠度的无参照分布式监测

IF 5.6 1区工程技术 Q1 ENGINEERING, CIVIL

Engineering Structures

Pub Date : 2024-11-14 DOI: 10.1016/j.engstruct.2024.119277

Dario Poloni , Maurizio Morgese , Chengwei Wang , Todd Taylor , Marco Giglio , Farhad Ansari , Claudio Sbarufatti

The research presented herein pertains to developing a reference-free technique for monitoring bridge deflections under operational conditions. The method is based on monitoring the distributed strains along the length of bridges and employing the Inverse Finite Element Method (iFEM) to compute the deflection for the entire length of bridges. Distributed sensing of strains was achieved by a Brillouin Optical Time Domain Analysis system (BOTDA). The dynamic strains were then used in the iFEM algorithm to calculate the deflections of the structure. This approach computes structural displacements by a variational principle with minimal computational cost. Because of its independence from loads and material properties, the proposed methodology monitors the dynamic deflections during bridge routine traffic operations, and it is potentially viable for real-time monitoring. The approach is validated through two comprehensive case studies, including a laboratory experiment and a field application on a multi-span concrete bridge.

本文介绍的研究涉及开发一种无参照物技术，用于监测运营条件下的桥梁挠度。该方法基于监测桥梁沿长度方向的分布应变，并采用反有限元法 (iFEM) 计算桥梁全长的挠度。布里渊光学时域分析系统 (BOTDA) 实现了对应变的分布式传感。动态应变随后被用于 iFEM 算法，以计算结构的挠度。这种方法通过变分原理计算结构位移，计算成本最低。由于该方法不受荷载和材料特性的影响，因此可在桥梁日常交通运营期间监测动态挠度，并可用于实时监测。通过两项综合案例研究，包括实验室实验和多跨混凝土桥梁的现场应用，对该方法进行了验证。

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引用次数: 0

Experimental investigation on failure mechanism of stepped footings rocking on bedrock 基岩上阶梯式基脚摇晃破坏机理的实验研究

IF 5.6 1区工程技术 Q1 ENGINEERING, CIVIL

Engineering Structures

Pub Date : 2024-11-14 DOI: 10.1016/j.engstruct.2024.119300

Xingji Lu , Jinhua Lu , Fangjun Wang , Haoyuan Gao

The gravity pier with a multiple-step footing is a common substructure system in railway bridges in China, particularly on bedrock. Rocking of this system benefits its seismic performance during the earthquake, but the cantilever part of the stepped footing is vulnerable since it is loaded with a large eccentricity, which has not been well studied. The present paper investigates the failure mechanisms and load capacity of two-layer stepped footing, based on two quasi-static tests and twenty finite element analyses, where four parameters in the stepped footing are studied: the longitudinal reinforcement ratio, the shear span to depth ratio, the critical contact area ratio, and the aspect ratio. In all investigations, the bottom step of the footings fails in flexure. The two quasi-static tests reveal that with the increase of the longitudinal reinforcement ratio in the footing, the load capacity at peak increases, and the damages at the footing are slighter, whereas the damages at the pier body become severe. The finite element models of the two test specimens are first built, and the validations show the finite element results agree well with the test results. The remaining finite element analyses further find that increasing the critical contact area ratio, increasing the aspect ratio, or decreasing the shear span to depth ratio significantly reduces the extent of damage to the footing and increases the load capacities at different damage states. Moreover, the investigations also find damages at the pier body are influenced by the four parameters studied. As the longitudinal reinforcement ratio or critical contact area ratio increases, the damages at the pier body become severe. Whereas, increasing the shear span to depth ratio or the aspect ratio results in slighter damages at the pier body.

重力式多台阶墩台是中国铁路桥梁中常见的下部结构体系，尤其是在基岩上。在地震中，这种体系的摇动有利于其抗震性能，但由于阶梯式基脚的悬臂部分受力偏心较大，因此容易受到影响，这一点尚未得到很好的研究。本文基于两次准静力试验和二十次有限元分析，研究了两层阶梯式基脚的破坏机理和承载能力，其中研究了阶梯式基脚的四个参数：纵向配筋比、剪切跨度与深度比、临界接触面积比和长宽比。在所有研究中，基脚底部阶梯都发生了弯曲破坏。两次准静力试验表明，随着基脚纵向配筋率的增加，峰值承载力也随之增加，基脚处的破坏较轻，而墩身处的破坏则变得严重。首先建立了两个试件的有限元模型，验证表明有限元结果与试验结果吻合良好。其余的有限元分析进一步发现，增大临界接触面积比、增大长宽比或减小剪切跨度与深度比，都能显著减小基脚的损坏程度，并提高不同损坏状态下的承载能力。此外，研究还发现墩身的损坏也受到所研究的四个参数的影响。随着纵向配筋率或临界接触面积比的增大，墩身的损坏会变得严重。而增加剪切跨度与深度比或纵横比则会使墩身的损坏程度减轻。

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引用次数: 0

Stress field models for discontinuity regions in steel-reinforced laminated glass 钢增强夹层玻璃不连续区域的应力场模型

IF 5.6 1区工程技术 Q1 ENGINEERING, CIVIL

Engineering Structures

Pub Date : 2024-11-13 DOI: 10.1016/j.engstruct.2024.119287

Mirko Pejatović, Robby Caspeele, Jan Belis

This article presents the application of stress field models for strength prediction of discontinuity regions in steel-reinforced glass structures failing due to crushing of the glass and failure of stainless steel reinforcement. One of the main assumptions in the proposed modelling approach is that the structural laminated glass has similar compressive features as high-strength concrete within a framework of the stress field method. The paper initially introduces theoretical and experimental aspects and similarities between compressive behaviour of glass and high-strength concrete. Considerations on the compressive strength of laminated glass as well as the softening effect of cracks through the transverse strain factor are presented. The softening effect of cracks is investigated using the results of bending tests on beams and detailed digital image correlation (DIC) measurements. Finally, the proposed models are compared with results of tests on steel-reinforced glass members encompassing local compressive tests, bending tests and tests on beam-column connections. Additionally, the three groups of tests are numerically simulated using elastic-plastic stress fields (EPSF), through the finite element (FE) software EvalS for the automatic development of 2D stress fields. This numerical tool was originally developed for design and assessment of RC discontinuity regions. It is found that the numerical predictions are in a good agreement with test results. It is concluded that the stress fields may serve as a tool for the verification of a post-fracture limit state.

本文介绍了应力场模型在钢筋玻璃结构不连续区域强度预测中的应用，不连续区域是由于玻璃破碎和不锈钢钢筋失效而造成的。所提议的建模方法的主要假设之一是，在应力场方法框架内，结构夹层玻璃具有与高强度混凝土类似的抗压特征。本文首先介绍了理论和实验方面的内容，以及玻璃和高强度混凝土抗压行为的相似性。论文介绍了夹层玻璃的抗压强度以及通过横向应变因子产生的裂缝软化效应。利用梁的弯曲试验结果和详细的数字图像相关（DIC）测量结果研究了裂缝的软化效应。最后，将提出的模型与钢筋玻璃构件的试验结果进行了比较，包括局部抗压试验、弯曲试验和梁柱连接试验。此外，还通过有限元（FE）软件 EvalS 自动生成二维应力场，使用弹塑性应力场（EPSF）对三组试验进行了数值模拟。该数值工具最初是为设计和评估 RC 不连续区域而开发的。结果发现，数值预测与测试结果非常吻合。结论是应力场可作为验证断裂后极限状态的工具。

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