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IABSE Congress, Nanjing 2022: Bridges and Structures: Connection, Integration and Harmonisation最新文献

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FE Modeling of the Interfacial Behaviour of Precast Multi-box Girder 预制多箱梁界面性能有限元模拟
Juhui Zhang, Yuchuan Zhao
To facilitate the reuse of the internal mold of precast multi-box girder and accelerate bridge construction, the torsional crossbeam at the end of precast simply supported multi-box girder needs to be changed to post-cast in-situ. Finite Element Modelling package ABAQUS 2021 was used to model the interfacial shear behaviour of the three-dimensional Z-shaped straight shear specimens. The models took into account the bond-slip relationship between the old and new concrete interfaces and the interaction between the concrete and the shear key. The models were validated and calibrated based on the experimental results. The study shows that the rigid shear key can improve the shear load capacity of the specimen at the new and old concrete interface. The difference between the model and experimental results is relatively small and therefore it shows the capability of the finite element modelling to carry out parametric analysis.
为方便预制多箱梁内部模具的再利用,加快桥梁施工,需要将预制简支多箱梁端部扭梁改为现浇后浇。采用有限元建模软件ABAQUS 2021对三维z形直剪试件的界面剪切行为进行建模。模型考虑了新旧混凝土界面的粘结滑移关系以及混凝土与剪力键的相互作用。根据实验结果对模型进行了验证和标定。研究表明,刚性剪切键可以提高试件在新旧混凝土界面处的抗剪承载力。模型与实验结果的差异较小,显示了有限元建模进行参数化分析的能力。
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引用次数: 0
Beneficial Effect of Combining Similar Low-Cost Accelerometer to improve the overall Accuracy and Noise Density 同类低成本加速度计组合对提高整体精度和噪声密度的有利影响
S. Komarizadehasl, Ahmad Alahmad, J. Lozano-Galant, V. Torralba, G. Ramos, J. Turmo
Structural Health Monitoring applications are receiving more and more attention nowadays. The epidemic problem with these evaluations is their high cost. For applying them to structures/ infrastructures with a low budget of SHM evaluations, low-cost sensors must be taken into account. However, low-cost accelerometers have higher noise density ratios which affect their accuracy and resolution. Using filters or post-processing methods alters the acquired information of the accelerometers. This article aims to enhance the accuracy and resolution of low-cost sensors by improving and controlling the spectral noise level through active noise improvement. This improvement is studied in this paper and supportive laboratory experiments have been illustrated.
结构健康监测的应用越来越受到人们的重视。这些评价的普遍问题是它们的高成本。为了将其应用于SHM评估预算较低的结构/基础设施,必须考虑低成本传感器。然而,低成本加速度计具有较高的噪声密度比,影响其精度和分辨率。使用滤波器或后处理方法改变加速度计的采集信息。本文旨在通过主动噪声改善来改善和控制频谱噪声水平,从而提高低成本传感器的精度和分辨率。本文对这种改进进行了研究,并举例说明了支持性的实验室实验。
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引用次数: 0
Prediction of Aerodynamic Coefficients using Artificial Neural Network in Shape Optimization of Centrally-Slotted Box Deck Bridge 基于人工神经网络的中开槽箱式桥面优化气动系数预测
Mohammed Elhassan, Ledong Zhu, Z. Tan, Wael Alhaddad
Aerodynamic shape optimization of bridge deck is a very important task in the wind-resistant design of long-span bridges and often carried out via wind tunnel tests of sectional model or CFD simulation, both of which commonly need heavy workload, thus are time-consuming and costly. In this paper, an artificial neural network (ANN) model was developed to predict aerodynamic coefficients of a central-slotted box deck of a 1600m main span cable-stayed bridge during the aerodynamic shape optimization to enhance its performance of wind-induced static stability. The ANN model was built and trained with a data set of aerodynamic coefficients obtained from limited cases of wind tunnel tests. The effect of neuron numbers in the hidden layer on prediction accuracy was discussed. The results show that the built ANN model can accurately predict the aerodynamic coefficients and significantly reduce the workload of wind tunnel tests.
桥面气动形状优化是大跨径桥梁抗风设计中的一项重要任务,通常通过截面模型风洞试验或CFD模拟进行,但这两种方法工作量大,耗时长,成本高。为提高某主跨1600m斜拉桥中央开槽箱型桥面的风致静稳定性,建立了人工神经网络模型,对其气动外形优化过程中的气动系数进行预测。利用有限风洞试验的空气动力系数数据集建立了人工神经网络模型并进行了训练。讨论了隐层神经元数对预测精度的影响。结果表明,所建立的人工神经网络模型能够准确预测气动系数,显著减少风洞试验工作量。
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引用次数: 0
Resilience Quantification Based on Monitoring & Prediction Data Using Artificial Intelligence (AI) 基于人工智能监测与预测数据的弹性量化
D. Achillopoulou, N. K. Stamataki, A. Psathas, L. Iliadis, A. Karabinis
Lately, there is an increasing demand for resilient infrastructure assets. To support the documentation of resilience, Structural Health Monitoring (SHM) data is a necessity, as well as traffic loads. Those diagnosis and function data can be the basis for the prognosis of future prediction for the performance of the assets. Towards this direction, this paper develops a new methodology that uses real monitoring data and Artificial Intelligence (AI) algorithms to quantify the resilience based on future traffic load predictions of functionality. It includes the case study of the “Hollandse Brug” bridge in the Netherlands considering strains and traffic load predictions and other external. Resilience is derived as a function of both functional and structural parameters throughout the lifecycle. The quantification is supported by sustainability indices and key performance indicators representing the traffic flow, the structural integrity and the sustainability level of the asset.
最近,对弹性基础设施资产的需求不断增加。为了支持弹性文档,结构健康监测(SHM)数据以及流量负载是必要的。这些诊断和功能数据可以作为预测未来资产性能的基础。朝着这个方向,本文开发了一种新的方法,该方法使用真实的监控数据和人工智能(AI)算法来量化基于未来交通负荷预测的功能的弹性。它包括荷兰“Hollandse Brug”大桥的案例研究,考虑了压力和交通负荷预测以及其他外部因素。弹性是整个生命周期中功能和结构参数的函数。量化由可持续性指数和关键绩效指标支持,这些指标代表了交通流量、结构完整性和资产的可持续性水平。
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引用次数: 1
Structural Performance and Cost Analysis of Multi-span Extradosed Cable-Stayed Bridge 多跨斜拉桥结构性能及造价分析
Z. Xiong, Xu Hou, Houda Zhu, Yuqing Liu, Yang Meng
To investigate the structural performance and economic applicability of multi-span extradosed cable-stayed bridge, a comparative scheme of composite beam with corrugated steel web was designed based on the Wangjia River Bridge, which was an extradosed cable-stayed bridge with prestressed concrete girder built in Shaanxi. Spatial finite element models of the whole bridge were established by CSIBridge for extradosed cable-stayed bridge with two different sections of girder. Considering the influence of p-Δ effect, the vertical and horizontal deformation and the governing sections of the two forms were analyzed and compared. The material consumption of steel, concrete and steel strand of the extradosed cable-stayed bridge with corrugated steel web was calculated. The material consumption of the two schemes was compared. The differences in structural performance and economic cost for the two structures were explored. It’s expected to provide a reference for the tender design of multi-span extradosed cable-stayed bridges with similar span length.
为研究多跨外延斜拉桥的结构性能和经济适用性,以陕西王家河特大桥为例,设计了波纹钢腹板组合梁对比方案。采用CSIBridge软件建立了两段不同主梁的斜拉桥的全桥空间有限元模型。考虑p-Δ效应的影响,对两种形式的竖向、水平变形及控制断面进行了分析比较。计算了波纹钢腹板外延斜拉桥的钢材、混凝土和钢绞线的材料消耗量。比较了两种方案的材料消耗。探讨了两种结构在结构性能和经济成本上的差异。期望为类似跨径的多跨斜拉桥的投标设计提供参考。
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引用次数: 2
Structural Detailing of Bridges, Making Use of the Brim Methodology (Bridge Information Modeling), through the Creation of Parametric Models and As-Build Plans 桥梁的结构细节,利用Brim方法(桥梁信息建模),通过创建参数化模型和建造计划
Álvaro Rojas, M. Valenzuela, Alvaro Peña
Within a project related to the area of bridges, we work with different tools and between this information is usually managed through the use of CAD drawings made basically in 2D.Today, a new concept of BIM applied to bridges called Bridge Information Modeling (BrIM), which well implies being a methodology with different uses and being the solution in helping the different parties to work more collaboratively, effectively and simultaneously.This paper presents the experience of applying one of these uses in the phase of analysis and structural diagnosis of ten bridges in Chile, which demonstrates that this technology becomes a valuable tool for information management through the virtual model worked between the different parties involved in the maintenance and operation of a project.
在一个与桥梁领域相关的项目中,我们使用不同的工具,这些信息通常是通过使用CAD制图来管理的,基本上是2D的。今天,BIM的一个新概念应用于桥梁,称为桥梁信息模型(BrIM),这意味着它是一种具有不同用途的方法,是帮助不同各方更有效、更协同、更同步地工作的解决方案。本文介绍了在智利10座桥梁的分析和结构诊断阶段应用其中一种用途的经验,这表明,通过在项目维护和运营中涉及的不同各方之间工作的虚拟模型,该技术成为信息管理的宝贵工具。
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引用次数: 0
Aerodynamic Parameter Identification and Flutter Performance Prediction of Closed Box Girder Based on Machine Learning 基于机器学习的箱梁气动参数识别及颤振性能预测
Neyu Chen, Y. Ge
A bridge wind resistance database has been built based on the wind tunnel testing results of 20 long-span bridges. The artificial intelligence models for identifying aerostatic coefficients and flutter derivatives of close box girders are trained and developed via machine learning methods, including error back propagation neural network based on Levenberg-Marquardt algorithm and gradient boosting decision tree. The identification of the aerostatic coefficients can be achieved with high accuracy. For flutter derivatives, the model can also explore the underlying distribution of dataset. In this way, the present research work can make the identification of aerodynamic parameters separated from tedious wind tunnel test and complex numerical simulation to some extent. It can also provide a convenient and feasible option for expanding data sets of aerodynamic parameters. In addition, it can help determine the appropriate shape of the box girder cross-section in preliminary design stage of long-span bridge and provide the necessary reference for the aerodynamic shape optimization by modifying local geometric features of the cross-section to evaluate the influence of the aerodynamic shape on flutter performance.
以20座大跨度桥梁的风洞试验结果为基础,建立了桥梁风阻数据库。采用基于Levenberg-Marquardt算法的误差反向传播神经网络和梯度增强决策树等机器学习方法,建立了用于箱梁气动静力系数和颤振导数识别的人工智能模型。气动系数的辨识具有较高的精度。对于颤振导数,该模型还可以探索数据集的底层分布。这样,本研究工作可以在一定程度上使气动参数的识别从繁琐的风洞试验和复杂的数值模拟中分离出来。它还为扩展气动参数数据集提供了一种方便可行的选择。此外,通过对箱梁截面局部几何特征的修改,可以在大跨度桥梁初步设计阶段确定合适的箱梁截面形状,并为气动形状优化提供必要的参考,以评估气动形状对颤振性能的影响。
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引用次数: 0
Investigation on the Unsteady Aerodynamic Force on a 3:2 Rectangular Section under Accelerating Airflow 加速气流作用下3:2矩形截面非定常气动力研究
Xiuyu Chen, Ledong Zhu, Z. Tan

Unsteady characteristics of aerodynamic force and wind-induced pressure on a 3:2 rectangular section under accelerating airflow are investigated through wind tunnel experiments. Three aerodynamic coefficients, drag coefficient Cd(t), RMS of lift coefficient Clrms(t), Strouhal number of the rectangular section in the accelerating airflow with or without initial velocity are compared with those of the steady flow. Results show that in the cases of airflow accelerated from the static state, significant unsteady feature appears in all three aerodynamic coefficients, 𝐶𝐶𝑑𝑑(𝑡𝑡) and

Clrms(t) decreases and St number increases in the early accelerating stage. For accelerating airflow with an initial velocity, the three aerodynamic characteristics fit well with steady flow values, indicating negligible impact on any of these variables.

通过风洞试验研究了加速气流作用下3:2矩形截面上的气动力和风致压力的非定常特性。对有初速度和无初速度加速气流中矩形截面的阻力系数Cd(t)、升力系数Clrms(t)的RMS、斯特劳哈尔数三个气动系数进行了比较。结果表明:当气流从静态加速时,3个气动系数均表现出明显的非定常特征,在加速初期,各系数(𝑑𝑑(𝑡𝑡)和clrms (t)均减小,St数增加;对于初速加速气流,三个气动特性与定常流值吻合良好,表明对这些变量的影响可以忽略不计。
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引用次数: 0
Analytical Methods to Adjust the Distribution of Dead Loads of a Suspension Bridge with Three Cable Planes to Three Cables in The Transverse Direction 三索面悬索桥横向三索面自重分布调整的解析方法
Wenmin Zhang, Ji-jiu Liu, Zihang Liu
Suspension bridges with three cable planes (SB-3CP) provide an excellent solution to the suspension bridges’ downwarp problem with ultrawide decks. However, the middle cable bears most of the deck load, which affects the torsional rigidity, and force status of the upper transverse beam on the pylon. It is necessary to adjust the distribution of dead loads to three cables in the transverse direction. In this paper, two analytical methods respectively based on the hanger cross sectional area (Method 1) and unstrained length (Method 2) are proposed. By altering the cross- sectional area of each hanger (Method 1) and increasing the unstrained length of the middle hanger (Method 2), the load share beard by the middle cable reduces. Finally, an SB-3CP was taken as an example. As the results show, the more load the side cable bears, the more torsional rigidity the bridge has, and the less vertical force is applied by the main cable to the upper transverse beam on the pylon.
三索面悬索桥(SB-3CP)为超宽桥面悬索桥的下曲问题提供了一种极好的解决方案。然而,中缆承担了大部分甲板荷载,影响了塔上横梁的扭转刚度和受力状态。有必要在横向上调整三根电缆的自重分布。本文提出了两种基于吊架截面面积的分析方法(方法1)和基于非应变长度的分析方法(方法2)。通过改变每个吊架的横截面积(方法1)和增加中间吊架的非应变长度(方法2),减少了中间电缆的荷载分担。最后,以SB-3CP为例。结果表明,侧索承受的荷载越大,桥梁的扭转刚度越大,主索对塔架上横梁施加的竖向力越小。
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引用次数: 0
Probabilistic Assessment of Vehicle Driving Safety under Strong Winds – Cause Investigations on Two Sea-Crossing Bridges 大风条件下车辆行驶安全的概率评估——两座跨海大桥原因调查
Hoki Kim, Hyeong-Yun Cheon, Sejin Kim
The strong side winds threaten the stability of running vehicles over the sea-crossing bridges due to the high altitude of the deck and free exposure to the upcoming winds. Therefore, bridge operators control the speed limit or close the bridges when the wind speed reaches predetermined criteria. Since the sea-crossing bridges play an essential role in transportation networks, the traffic control strategy, including complete closure, requires a careful assessment of the critical wind speed at which vehicle instability can occur. As the aerodynamic forces on vehicles depend on several influence factors, including the geometrical shape of the superstructure, the critical wind speeds variate bridge by bridge. This study demonstrates a framework to determine the critical wind speed. This study reports two overturning accidents experienced in a double-deck suspension bridge and a cable-stayed bridge. By applying the proposed framework to the cases, the authors successfully explained the cause of accidents. For this investigation, the authors used a wind tunnel measurement of aerodynamic loads on vehicles and the vehicle dynamics to determine critical wind speed curves. The authors also extended the procedure to the probabilistic risk assessment by adding the long-term wind data analysis of the bridge site. In this way, this study provides a guideline for bridge operators on balancing the driving safety and the continuous mobility of the sea-crossing bridges under hazardous high wind conditions.
由于甲板的高度和即将到来的风的自由暴露,强大的侧风威胁着在跨海桥梁上运行的车辆的稳定性。因此,当风速达到预定标准时,桥梁运营商控制速度限制或关闭桥梁。由于跨海大桥在交通网络中起着至关重要的作用,交通控制策略,包括完全关闭,需要仔细评估可能发生车辆不稳定的临界风速。由于车辆所受的气动力取决于包括上部结构几何形状在内的多种影响因素,因此不同桥梁的临界风速不尽相同。本研究展示了一个确定临界风速的框架。本文报道了两座双层悬索桥和一座斜拉桥的倾覆事故。通过将提出的框架应用到案例中,作者成功地解释了事故的原因。在这项研究中,作者使用风洞测量车辆的空气动力载荷和车辆动力学来确定临界风速曲线。作者还通过增加桥址长期风数据分析,将程序扩展到概率风险评估。从而为跨海桥梁在危险大风条件下平衡行车安全和持续机动提供指导。
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引用次数: 0
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IABSE Congress, Nanjing 2022: Bridges and Structures: Connection, Integration and Harmonisation
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