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学者姓名:贾俊峰
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Abstract :
Ultra-high performance concrete (UHPC) has been widely used in wet joints of precast bridge deck panels (PBDPs) due to its remarkable compressive strength, excellent tensile strength, and exceptional durability properties. However, there is a lack of consistent understanding regarding the mechanical properties of PBDPs with UHPC wet joints, especially shear behavior. To investigate the shear performance of PBDPs with UHPC wet joints, a total of seven bridge deck panels (BDPs) were designed and conducted by four-point bending tests. The test parameters included reinforcement types (straight bar and U-bar), lap details (contact lap and non-contact lap), joint widths (150 mm, 200 mm, 250 mm, and 500 mm), and filling materials (NC and UHPC). According to the test results, the shear behavior of seven BDPs was analyzed. The experiment results showed that all specimens exhibited shear failure, with critical shear cracks occurring in the shear span. For PBDPs with U-bars, the shear capacity of 200-mm-wide UHPC wet joints was 1.5 % higher than that of 500-mm-wide NC wet joints. In addition, the failure pattern had a tendency to gradually shift from shear failure to flexural failure when the width of UHPC wet joints was reduced from 250 mm to 150 mm. To establish 3D finite element (FE) models, a cohesion-friction hybrid model was proposed. The FE models had good simulation accuracy, with a maximum deviation of 7.0 %. Furthermore, a parametric analysis was performed to assess the influence of critical parameters on shear performance. The results showed that longitudinal reinforcement has a greater influence on the shear performance of PBDPs. Finally, shear capacity formulas in the design codes were verified in comparison with test results. The deviation of theoretically calculated values from test results was within 10 %.
Keyword :
UHPC wet joint UHPC wet joint Shear behavior Shear behavior Precast bridge deck panel Precast bridge deck panel Cohesion-friction hybrid model Cohesion-friction hybrid model Four -point bending test Four -point bending test Shear capacity Shear capacity
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GB/T 7714 | Ren, Zhangdi , Jia, Junfeng , Li, Jian et al. Shear behavior of precast bridge deck panels with UHPC wet joints [J]. | ENGINEERING STRUCTURES , 2024 , 316 . |
MLA | Ren, Zhangdi et al. "Shear behavior of precast bridge deck panels with UHPC wet joints" . | ENGINEERING STRUCTURES 316 (2024) . |
APA | Ren, Zhangdi , Jia, Junfeng , Li, Jian , Hu, Menghan , Li, Bin , Han, Qiang et al. Shear behavior of precast bridge deck panels with UHPC wet joints . | ENGINEERING STRUCTURES , 2024 , 316 . |
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Abstract :
A new type of fiber-reinforced polymer (FRP) with a tensile rupture strain of more than 5% was used for the seismic retrofitting of reinforced concrete (RC) square columns in this paper. A control column and 9 FRPwrapped RC square columns were prepared with different number of FRP layers and FRP types. The seismic performance was comprehensively discussed and analyzed in terms of the failure modes, hysteretic behaviors, cumulative energy dissipation and FRP strain evolution. Experimental results showed that the ductility of specimens had a remarkable improvement as the confinement stiffness increased. Moreover, the buckling of longitudinal bars was restricted and postponed. Numerical analysis was conducted in OpenSees to further research the seismic performance of specimens based on an LRS FRP-confined concrete model and a reinforcing bar buckling model considering FRP confining effect. The simulated results were in close agreement with the experimental results. Parametric analysis was also conducted to investigate the influence of the FRP wrapping thickness, axial compression ratio and longitudinal reinforcement ratio on the seismic performance.
Keyword :
Buckling of longitudinal reinforcements Buckling of longitudinal reinforcements Large-rupture-strain fiber-reinforced polymer Large-rupture-strain fiber-reinforced polymer Seismic performance Seismic performance (LRS FRP) (LRS FRP) FRP-strengthened RC square column FRP-strengthened RC square column
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GB/T 7714 | Bai, Yu-Lei , Bai, Shang-Cong , Mei, Shi-Jie et al. Seismic behavior of RC square columns strengthened with LRS FRP under high axial load ratio [J]. | STRUCTURES , 2023 , 56 . |
MLA | Bai, Yu-Lei et al. "Seismic behavior of RC square columns strengthened with LRS FRP under high axial load ratio" . | STRUCTURES 56 (2023) . |
APA | Bai, Yu-Lei , Bai, Shang-Cong , Mei, Shi-Jie , Jia, Jun-Feng , Yang, Kai . Seismic behavior of RC square columns strengthened with LRS FRP under high axial load ratio . | STRUCTURES , 2023 , 56 . |
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Abstract :
This paper investigates the cyclic behavior of a steel self-centering (SC) rocking column. The steel SC rocking column consists of an H-section steel column and a pair of shape memory alloy (SMA) slip-friction dampers (SMASFDs). As the kernel part, the SMASFDs enhance SC capability of the rocking column and dissipate the input energy. The working principle of the rocking column is first described, along with the analytical equations that govern the behavior under loading cycles, which are validated by experimental data. The component tests were conducted on the NiTi SMA bar and the slip-friction mechanism, separately. And then, the cyclic loading tests were conducted on a 1:2-scaled rocking column specimen. The considered axial force ratio included 0, 0.1 and 0.2. During the entire experimental procedure, the SMA bars were neither repaired nor replaced. It is found that up to a drift ratio of 7 %, the rocking column maintained stable flag-shaped hysteresis, which is characterized by excellent SC capability and satisfactory damping capacity. The testing results also indicated that increasing axial force ratio effectively increased the strength and stiffness of the rocking column, whereas it reduced the post -decompression stiffness due to the P-Delta effect. Finally, the numerical models were established in ABAQUS and OpenSees, both of which were verified by the experimental data, and a parametric study was carried out.
Keyword :
Shape memory alloy (SMA) Shape memory alloy (SMA) Experimental test Experimental test Rocking column Rocking column
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GB/T 7714 | Qiu, Canxing , Liu, Jiawang , Jiang, Tianyuan et al. Experimental study on a steel self-centering rocking column with SMA slip friction dampers [J]. | ENGINEERING STRUCTURES , 2023 , 274 . |
MLA | Qiu, Canxing et al. "Experimental study on a steel self-centering rocking column with SMA slip friction dampers" . | ENGINEERING STRUCTURES 274 (2023) . |
APA | Qiu, Canxing , Liu, Jiawang , Jiang, Tianyuan , Jia, Junfeng , Du, Xiuli . Experimental study on a steel self-centering rocking column with SMA slip friction dampers . | ENGINEERING STRUCTURES , 2023 , 274 . |
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Abstract :
精确的有限元分析(FEA)依赖于材料的准确定义。通过编写用户子程序UMAT实现了大断裂应变纤维增强聚合物(LRS FRP)在纤维方向上拉伸特性的定义。基于Abaqus中混凝土塑性损伤模型的理论框架,提出了一种改进的混凝土塑性损伤模型用于定义LRS FRP约束混凝土的材料特性。这些改进包括:通过LRS FRP约束混凝土的实验数据校准了与屈服准则相关的参数K;硬化/软化准则与约束刚度相关;流动法则与轴向塑性应变相关。采用修改后的材料模型进行FEA,结果表明:FEA预测的应力-应变曲线与实验结果吻合。基于FEA的结果,讨论了矩形柱截面上应力分布的不均匀性,根据约束效果可分为有效约束区域和弱约束区域,且在约束有效区域上应力分布不均匀性随着截面比(长边/短边)的增加而增加。
Keyword :
大应变FRP 大应变FRP 约束混凝土 约束混凝土 混凝土塑性损伤模型 混凝土塑性损伤模型 纤维增强聚合物(FRP) 纤维增强聚合物(FRP) 有限元分析 有限元分析
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GB/T 7714 | 白玉磊 , 杨洪龙 , 贾俊峰 et al. 基于修正混凝土塑性损伤模型的大应变FRP约束混凝土有限元分析 [J]. | 工程力学 , 2023 , 40 (4) : 129-143 . |
MLA | 白玉磊 et al. "基于修正混凝土塑性损伤模型的大应变FRP约束混凝土有限元分析" . | 工程力学 40 . 4 (2023) : 129-143 . |
APA | 白玉磊 , 杨洪龙 , 贾俊峰 , 梅世杰 . 基于修正混凝土塑性损伤模型的大应变FRP约束混凝土有限元分析 . | 工程力学 , 2023 , 40 (4) , 129-143 . |
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Abstract :
Buckling of the longitudinal rebar is one of the main forms of plastic hinge failure in reinforced concrete (RC) columns after an earthquake. This rebar buckling significantly impacts the seismic bearing capacity and energy dissipation capacity. To restrain the development of longitudinal rebar buckling behavior and delay the degradation of lateral strength in RC columns, this paper developed a new type of buckling restraint rebar (BRR) consisting of three components: longitudinal rebar, a restraint sleeve, and foam material. First, the BRR mechanical properties under compression and tension-compression cyclic loading were obtained through quasi-static loading tests. Then, the BRR compression and tension-compression cyclic loading processes were numerically simulated based on ABAQUS finite element software. The simulated results were compared with the test results. Finally, a stress-strain constitutive model for this new BRR was proposed based on this study. Results showed that the restraint sleeve could significantly enhance the lateral stiffness and the bearing capacity of longitudinal reinforcement after yielding. The compressive performance of BRR was mainly affected by the length and wall thickness of the sleeve. The cyclic performance was mainly affected by the length of the sleeve and the clearance between the sleeve and the reinforcement. The BRR constitutive model proposed in this paper can accurately reflect the influence of restraint sleeves on the stiffness of longitudinal reinforcement after yielding.
Keyword :
constitutive model constitutive model buckling behavior buckling behavior buckling restraint rebar (BRR) buckling restraint rebar (BRR) axial compression axial compression
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GB/T 7714 | Jia, Junfeng , Zhao, Nannan , Bai, Yulei et al. Mechanical properties and constitutive model of the buckling restraint rebar under compression loads [J]. | STRUCTURAL CONCRETE , 2023 , 24 (5) : 6070-6086 . |
MLA | Jia, Junfeng et al. "Mechanical properties and constitutive model of the buckling restraint rebar under compression loads" . | STRUCTURAL CONCRETE 24 . 5 (2023) : 6070-6086 . |
APA | Jia, Junfeng , Zhao, Nannan , Bai, Yulei , Cao, Yanhui , Cheng, Shoushan , Fan, Ping . Mechanical properties and constitutive model of the buckling restraint rebar under compression loads . | STRUCTURAL CONCRETE , 2023 , 24 (5) , 6070-6086 . |
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Abstract :
The vibration signal analysis-based structural health monitoring (SHM) system has been widely used for bridge condition identification. With the development of artificial intelligence (AI), machine learning (ML) has made numerous breakthroughs in the detection of civil engineering structures. However, conventional data-driven ML methods heavily rely on prior knowledge for their performance. This paper proposes a deep learning (DL) model 1DCNN-BiLSTM for detecting small local structural changes of reinforced concrete (RC) beams, which applies the structure of the Inception module in GoogLeNet to one-dimensional convolution neural networks (1DCNNs) for feature extraction at different scales, and combines the advantages of bidirectional long shortterm memory (BiLSTM) modules for processing long time-series data. Firstly, a three-dimensional numerical model of the RC beam was established using finite element software, and the accuracy of the numerical model was verified by comparing it with the test results. Based on the numerical model, tests on RC beams impacted by falling hammers were carried out, and the acceleration signals of the beam in different states were collected as a dataset. The proposed DL model can automatically extract the spatial and temporal domain features in the signals, accurately identify the location of small bridge local variations, the accuracy in the test set is 98.8% compared to 92.6% for a traditional ML model, and has better noise immunity performance and robustness to the missing data than the traditional ML model. Finally, the internal inference process of the model was explored and visualized, illustrating that the model has adaptive learning capabilities.
Keyword :
Deep learning Deep learning Reinforced concrete beam Reinforced concrete beam Convolutional neural networks Convolutional neural networks Vibration signals Vibration signals Structural health monitoring Structural health monitoring Recurrent neural networks Recurrent neural networks
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GB/T 7714 | Chen, Xize , Jia, Junfeng , Yang, Jie et al. A vibration-based 1DCNN-BiLSTM model for structural state recognition of RC beams [J]. | MECHANICAL SYSTEMS AND SIGNAL PROCESSING , 2023 , 203 . |
MLA | Chen, Xize et al. "A vibration-based 1DCNN-BiLSTM model for structural state recognition of RC beams" . | MECHANICAL SYSTEMS AND SIGNAL PROCESSING 203 (2023) . |
APA | Chen, Xize , Jia, Junfeng , Yang, Jie , Bai, Yulei , Du, Xiuli . A vibration-based 1DCNN-BiLSTM model for structural state recognition of RC beams . | MECHANICAL SYSTEMS AND SIGNAL PROCESSING , 2023 , 203 . |
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Abstract :
超长、超重预制盖梁对运输和吊装设备提出了更高的要求,阻碍了全装配式桥梁技术的发展和工程推广,成为当前亟待解决的关键难题。发展结构合理的轻型化、高性能装配式盖梁是解决上述问题的可选方案,值得关注。首先,系统梳理了轻型化盖梁的关键技术及典型工程应用;其次,详细论述了轻型化盖梁的力学性能研究进展,阐明了轻型化盖梁的未来研究方向;最后,归纳了轻型化盖梁的抗剪、抗弯承载力计算方法和流程。研究结果表明:当预制模壳与核心混凝土粘结强度较高时,预制模壳盖梁的力学性能和破坏模式与现浇盖梁相近;UHPC空心薄壁盖梁具有较强的抗剪、抗裂性能。然而,推广轻型化盖梁仍面临着轻型盖梁内模固定及拆模、设计施工技术标准制定、轻型化盖梁-桥墩节点可靠连接及其抗震性能等问题,这些问题亟需完善和突破。
Keyword :
空心盖梁 空心盖梁 轻型化盖梁 轻型化盖梁 抗弯承载力 抗弯承载力 抗剪承载力 抗剪承载力 组合盖梁 组合盖梁
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GB/T 7714 | 刘慈军 , 霍龙飞 , 贾俊峰 et al. 轻型化装配式盖梁构造设计与计算方法研究进展 [J]. | 市政技术 , 2023 , 41 (12) : 1-11 . |
MLA | 刘慈军 et al. "轻型化装配式盖梁构造设计与计算方法研究进展" . | 市政技术 41 . 12 (2023) : 1-11 . |
APA | 刘慈军 , 霍龙飞 , 贾俊峰 , 刘浩 , 方春平 , 吕文舒 . 轻型化装配式盖梁构造设计与计算方法研究进展 . | 市政技术 , 2023 , 41 (12) , 1-11 . |
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Abstract :
为评估地震作用下大应变纤维增强聚合物(large rupture strain fiber reinforced polymer, LRS FRP)加固桥梁的抗震性能,以一典型三跨连续梁桥为例进行了研究。目前关于LRS FRP约束混凝土往复轴压模型的研究较少,限制了LRS FRP加固桥梁的抗震分析。因此介绍了作者课题组提出的简化LRS FRP约束混凝土往复轴压模型,根据此模型并结合地震易损性分析理论,基于OpenSees平台,采用增量动力分析(incremental dynamic analysis, IDA)方法,对三跨连续梁桥在LRS FRP加固前后的地震易损性进行了分析。结果表明:轻微损伤和中等损伤状态下桥梁墩柱基本处于未受损坏的线弹性阶段,LRS FRP加固对其地震易损性影响不大;严重破坏和完全倒塌状态下,未加固桥梁的损坏超越概率明显大于LRS FRP加固的桥梁。提出的简化LRS FRP约束混凝土往复轴压模型可为LRS FRP加固桥梁的抗震分析提供参考。
Keyword :
增量动力分析 增量动力分析 OpenSees OpenSees 桥梁工程 桥梁工程 地震易损性 地震易损性 桥梁墩柱 桥梁墩柱 LRS FRP LRS FRP
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GB/T 7714 | 白玉磊 , 张玉峰 , 梅世杰 et al. 大应变FRP加固连续梁桥地震易损性分析 [J]. | 哈尔滨工业大学学报 , 2023 , 55 (09) : 84-91 . |
MLA | 白玉磊 et al. "大应变FRP加固连续梁桥地震易损性分析" . | 哈尔滨工业大学学报 55 . 09 (2023) : 84-91 . |
APA | 白玉磊 , 张玉峰 , 梅世杰 , 贾俊峰 , 杜修力 . 大应变FRP加固连续梁桥地震易损性分析 . | 哈尔滨工业大学学报 , 2023 , 55 (09) , 84-91 . |
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Abstract :
为了可靠、准确地预测钢管混凝土(CFST)柱的轴向承载力,建立和解释集成机器学习的CFST柱轴向承载力预测模型.使用马氏距离评估CFST柱数据库质量,通过极限梯度提升(XGBoost)算法建立CFST柱轴向承载力预测模型,使用K折交叉验证(K-Fold CV)和树结构概率密度估计(TPE)算法寻找模型的最优超参数组合.采用不同评价指标将优化后XGBoost模型的预测值与已有方法和未优化XGBoost模型的计算值比较.使用SHAP方法给出XGBoost模型预测结果的整体和局部的解释.结果表明,经过超参数调整优化的XGBoost模型的性能超越了相关规范和经验公式的性能,且SHAP方法能够有效地解释XGBoost模型的输出.
Keyword :
SHAP SHAP 轴向承载力 轴向承载力 可解释性 可解释性 钢管混凝土(CFST)柱 钢管混凝土(CFST)柱 超参数优化 超参数优化 极限梯度提升(XGBoost) 极限梯度提升(XGBoost)
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GB/T 7714 | 陈曦泽 , 贾俊峰 , 白玉磊 et al. 基于XGBoost-SHAP的钢管混凝土柱轴向承载力预测模型 [J]. | 浙江大学学报(工学版) , 2023 , 57 (6) : 1061-1070 . |
MLA | 陈曦泽 et al. "基于XGBoost-SHAP的钢管混凝土柱轴向承载力预测模型" . | 浙江大学学报(工学版) 57 . 6 (2023) : 1061-1070 . |
APA | 陈曦泽 , 贾俊峰 , 白玉磊 , 郭彤 , 杜修力 . 基于XGBoost-SHAP的钢管混凝土柱轴向承载力预测模型 . | 浙江大学学报(工学版) , 2023 , 57 (6) , 1061-1070 . |
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Abstract :
Prestressed structures are widely employed in bridges and large-span spatial structures, and the accurate evaluation of prestress state is of great importance for structural maintenance. This paper reviews the nondestructive testing (NDT) and health monitoring techniques for structural effective prestress. Specifically, the fiber Bragg grating (FBG) sensor-based, magnetic-elastic (ME) sensor-based, dynamic response-based, ultrasonic guided wave (UGW)-based, electromechanical impedance (EMI)-based, and electrical resistance-based methods are reviewed in this paper. Firstly, the principle, application range, and measuring accuracy of each technique are introduced and analyzed, and the benefits and limitations of each technique are summarized: The FBG sensor and ME sensor take on high measuring accuracy and have been applied in practical engineering, but they are required to be preinstalled during structural construction; the dynamic response-based method is greatly effective in cable force assessment but not suitable for prestress evaluation of prestressed concrete (PSC) structures; the UGW-based, EMI-based, and electrical resistance-based methods have shown favorable potential for prestress assessment in laboratory experiments, but their feasibility and accuracy in practical engineering need to be verified. Secondly, the challenges and discussion of each method are discussed in the following four aspects: measuring range, reliability of measuring results, stability and durability considering long-term monitoring, and cost-efficiency. Finally, a decision tree is proposed to choose the most appropriate prestress evaluation method in a specific application scenario.
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GB/T 7714 | Jia, Junfeng , Zhang, Longguan , Ou, Jinping et al. Nondestructive Testing and Health Monitoring Techniques for Structural Effective Prestress [J]. | STRUCTURAL CONTROL & HEALTH MONITORING , 2023 , 2023 . |
MLA | Jia, Junfeng et al. "Nondestructive Testing and Health Monitoring Techniques for Structural Effective Prestress" . | STRUCTURAL CONTROL & HEALTH MONITORING 2023 (2023) . |
APA | Jia, Junfeng , Zhang, Longguan , Ou, Jinping , Chen, Xize . Nondestructive Testing and Health Monitoring Techniques for Structural Effective Prestress . | STRUCTURAL CONTROL & HEALTH MONITORING , 2023 , 2023 . |
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