| 装配式预应力可变桁架体系加固RC短梁抗弯性能试验 |
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| 引用本文： | 王磊,吴兵辉,张旭辉,戴理朝.装配式预应力可变桁架体系加固RC短梁抗弯性能试验[J].中国公路学报,2021,34(2):246-255. |
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| 作者姓名： | 王磊 吴兵辉 张旭辉 戴理朝 |
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| 作者单位： | 1. 长沙理工大学土木工程学院, 湖南长沙 410114;
2. 湘潭大学土木工程与力学学院, 湖南湘潭 411105 |
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| 基金项目： | 国家自然科学基金项目(52008035);湖南省创新研究群体项目(2020JJ1006);湖南省科技创新计划项目(2020RC4024);湖南省重点领域研发计划项目(2019SK2171)。 |
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| 摘 要： | 针对混凝土箱梁腹板开裂、跨中下挠等问题，提出一种装配式预应力可变桁架加固体系。该体系由可变桁架、预应力筋和固定斜杆组成，可变桁架通过锚杆固定于加固梁两侧，张拉预应力使桁架上顶加固梁产生反拱，以此来消除或减小梁体开裂和下挠等病害，随后用斜杆固定桁架形成劲性骨架，进一步提高加固结构刚度和承载力。首先对该体系进行介绍，然后设计4片钢筋混凝土梁进行抗弯加固试验，对加固效果及影响因素进行分析验证。研究结果表明：提出的体系具有良好的加固效果，能有效抑制和延缓裂缝发展，改善加固梁的刚度和承载能力；此次试验中，加固梁的开裂、屈服以及极限荷载分别提高了107.28%、70.92%、74.55%以上；锚杆直径对承载力影响较小，但粗锚杆能有效约束端锚板滑移，改善结构整体刚度；端锚板对加固效果影响较大，加强型端锚板能充分发挥钢桁架、钢绞线强度特征，提高构件的极限承载能力，尤其能有效改善其延性破坏特征，极限挠度提高60%以上。
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| 关 键 词： | 桥梁工程 装配式预应力可变桁架 抗弯性能试验 钢筋混凝土短梁 加固 |
| 收稿时间： | 2020-05-14 |
Flexural Behavior Test of Reinforced Concrete Short Beams Strengthened with Prefabricated Prestressed Variable Truss System |
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| WANG Lei,WU Bing-hui,ZHANG Xu-hui,DAI Li-zhao.Flexural Behavior Test of Reinforced Concrete Short Beams Strengthened with Prefabricated Prestressed Variable Truss System[J].China Journal of Highway and Transport,2021,34(2):246-255. |
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| Authors: | WANG Lei WU Bing-hui ZHANG Xu-hui DAI Li-zhao |
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| Affiliation: | 1. School of Civil Engineering, Changsha University of Science & Technology, Changsha 410114, Hunan, China;
2. School of Civil Engineering and Mechanics, Xiangtan University, Xiangtan 411105, Hunan, China |
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| Abstract: | A strengthening system of the prefabricated prestressed variable truss is proposed to resolve the problems of web cracking and midspan deflection in concrete box beams.The strengthening system is mainly composed of variable trusses,prestressing tendons,and fixed diagonals.The variable trusses are fixed on both sides of the strengthened beam by anchor rods.The lifting of the truss after the prestress tensioning causes a reverse arch of the strengthened beam to eliminate the cracking and deflection of the beams.Then,the truss fixed by the diagonals becomes a rigid frame to improve the stiffness and bearing capacity of the structure further.In this report,the strengthening system is introduced first.Four reinforced concrete beams were designed for flexural performance tests to analyze and verify the reinforcement effect and influencing factors of the system.The results show that the strengthening system has a significant reinforcement effect,improving the bending stiffness and bearing capacity of the concrete beams.This can effectively inhibit and delay the development of cracks.In the test,the cracking,yield,and ultimate loads increased by more than 107.28%,70.92%,and 74.55%,respectively.The diameter of the anchor rod had little effect on the bearing capacity,while the coarse anchor rod effectively restrained the sliding of the anchor plate,improving the stiffness of the structure.The end anchor plate had a significant influence on the reinforcement effect.A reinforced end anchor plate made full use of the strength characteristics of steel trusses and strands,thereby improving the ultimate capacity of the members,especially the ductility failure characteristics.The ultimate deflection of the beams after strengthening increased by more than 60%. |
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| Keywords: | bridge engineering prefabricated prestressed variable truss flexural behavior test reinforced concrete short beams strengthening |
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