| 新型大直径GFRP筋锚具设计及试验研究 |
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| 引用本文： | 侯苏伟,周泰翔,龙佩恒.新型大直径GFRP筋锚具设计及试验研究[J].中国公路学报,2021,34(7):258-269. |
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| 作者姓名： | 侯苏伟 周泰翔 龙佩恒 |
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| 作者单位： | 北京建筑大学 工程结构与新材料北京高校工程研究中心, 北京 102616 |
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| 基金项目： | 北京市教育委员会科技计划一般项目专项资金项目（KM202010016015）；国家自然科学基金项目（51508019）；北京建筑大学双塔计划-建大英才项目（JDYC20160206）；北京建筑大学市属高校基本科研业务费专项资金项目（X18115，X18091） |
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| 摘 要： | 针对单根大直径GFRP筋因体表比过大难以锚固的问题，对已有黏结楔式锚固体系作出改进，将直接浇筑于锚筒和筋材之间的黏结介质替代为环氧树脂并在装配前进行预制；在环氧树脂楔块与锚环之间设计锥角差以消除加载端的剪切效应。通过理论分析新型锚具的受力机理，推导出锚具内力的分布规律以及锚具承载能力估算公式，从而为设计尺寸提供依据；利用有限元软件ABAQUS对9组不同内坡角和锥角差的新型锚具进行受力模拟，得到一组最优设计参数使锚固系统承载力达到最大，据此制作实体锚具对Φ32 mm的GFRP筋材进行静力拉伸试验。结果表明：新型锚具的设计参数相互影响，锥角差显著影响内部结构受力，锥角差越大锚具承载力越大，但过大锥角差可能会产生过大径向压力从而对楔形体造成破坏。内坡角越大锚具承载力越大，但过大的内坡角会导致筋材所受夹持力过小从而发生整体滑脱破坏；以锚筒长度235 mm为例，其最优的内坡角可取10%，锥角差取0.5°；预制楔形块的轴向刚度和强度对新型锚固体系的影响巨大，楔形块加入轴向FRP筋可防止黏结介质拉裂，从而有效提高内部结构的整体工作性能；新型锚具能够将复杂应力状态后移至有效锚固区后部分，避免了加载端的剪切效应，在有效锚固段受力始终均匀变化，可充分发挥GFRP大直径筋材抗拉能力；以Φ32 mm的GFRP筋材为例，极限承载力可达629.4 kN，远超GFRP筋材标准承载力，最高锚固效率达到139.9%，破坏方式主要以炸丝为主，静力锚固性能可靠。
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| 关 键 词： | 桥梁工程 新型GFRP筋锚具 静力试验 锚固系统 有限元分析 |
| 收稿时间： | 2019-11-13 |
Design and Experimental Research on Novel Large Diameter GFRP Tendon Anchorage |
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| HOU Su-wei,ZHOU Tai-xiang,LONG Pei-heng.Design and Experimental Research on Novel Large Diameter GFRP Tendon Anchorage[J].China Journal of Highway and Transport,2021,34(7):258-269. |
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| Authors: | HOU Su-wei ZHOU Tai-xiang LONG Pei-heng |
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| Affiliation: | Beijing Higher Institution Engineering Research Center of Civil Engineering Structure and Renewable Material, Beijing University of Civil Engineering and Architecture, Beijing 102616, China |
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| Abstract: | In this study, the existing bonding wedge anchorage system was improved in view of the difficulty of anchoring a single large-diameter glass fiber reinforced polymer (GFRP) bar owing to its large surface ratio. The bonding medium cast directly between the anchor barrel and reinforcement was replaced by epoxy resin and prefabricated before assembly. A taper angle difference between the epoxy resin wedge and anchor ring was designed to eliminate the shear effect at the loading end. The distribution law of the internal force of the anchorage, and the formula for estimating the bearing capacity of the anchorage are deduced by the theoretical analysis of the stress mechanism of the new type anchorage, thus providing a basis for the design size. The finite element software ABAQUS was used to simulate the stress of nine groups of new anchors with different inner slope angles and cone angle differences, and a set of optimum design parameters were obtained to maximize the bearing capacity of the anchorage system. Based on this, a solid anchor is established to perform a static tension test on Φ32 mm GFRP bars. The results show that the design parameters of the new type of anchors are related: the cone angle difference significantly affects the internal structure of the force; the larger the cone angle difference, the greater the bearing capacity of the anchor. However, an excessive cone angle difference may produce excessive radial pressure, affecting the wedge, which causes damage. The larger the inner slope angle, the greater the bearing capacity of the anchor; however, an excessively large inner slope angle will cause the clamping force of the reinforcement to be too small, causing an overall slippage failure. Taking an anchor barrel length of 235 mm as an example, the optimal inner slope angle is 10%, and the taper angle difference is 0.5°. The axial rigidity and strength of the prefabricated wedge block have a significant influence on the novel anchor system. The addition of axial FRP ribs to the wedge block can prevent the bonding medium from cracking, and effectively improve the overall working performance of the internal structure. The new anchor can move the complex stress state to the back part of the effective anchoring area, avoiding the shear effect of the loading end, and the force at the effective anchoring section is always uniformly changed, fully utilizing the tensile capacity of the GFRP large-diameter reinforcement. Taking Φ32 mm GFRP bars as an example, the ultimate bearing capacity reaches 629.4 kN, considerably exceeding the standard bearing capacity of GFRP bars, and the highest anchoring efficiency reaches 139.9%. The main failure mode is wire-fried, and the static anchoring performance is reliable. |
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| Keywords: | bridge engineering new GFRP anchorage static test anchorage system finite element analysis |
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