预应力CFRP及预紧螺栓联合加固RC梁力学形为研究

发布时间：2019-01-22 13:02

【摘要】：现阶段预应力CFRP加固技术应用于危害桥梁加固工程中对于桥梁加固方法是一种极好的补充,改善了现有桥梁加固方法中的不足,采用预应力CFRP加固技术可以增大桥梁的极限承载能力,改善桥梁的力学性能,抑制裂缝的开展,减小桥梁的挠度变形,提高碳纤维布的有效利用率。但是将此项桥梁加固技术很好的应用于实际桥梁加固工程中存在着一定的问题,主要表现在碳纤维布预应力张拉系统上(现有张拉设备和锚固装置操作繁琐、占用空间大、对桥梁本身的损害大等问题)及施工工艺上。本文在现有张拉系统的基础和原理上,并结合碳纤维布本身的特点,设计研发了一套新型张拉系统;设计制作了 9根6m长的试验梁进行了大比例尺试验研究,更接近于实际桥梁工程;其中采用本套新型张拉系统对8根试验梁进行了预应力碳纤维布加固,分别对8根试验梁进行单层、双层、三层碳纤维布粘贴加固;所施加的初始预应力度分别为25%、50%和75%,并对8根试验梁采用机械锚固钢板进行锚固,对8根试验梁采用自制反力架进行四点弯曲加载。试验结果表明采用新研发的碳纤维布张拉系统可以完成对碳纤维布施加设定大小的初始应力,且设备安装操作方便,施工效率高;预应力CFRP及预紧螺栓联合加固技术加固钢筋混凝土梁可以有效的提高被加固梁极限承载能力,增大被加固梁的抗弯刚度,减小挠度变形,抑制裂缝的开展,使碳纤维布充分发挥了高强性能,改善桥梁的力学性能。通过对预应力碳纤维布加固RC梁力学性能分析研究,本文通过理论计算和试验结果分析对比了极限承载力、挠度变形,理论计算与试验结果吻合较好,总结了预应力碳纤维布及预紧螺栓联合加固桥梁的受力机理。采用此项加固技术设计加固了济菏高速G35线东平段的K137+128通道,效果显著,总结出了依托于此套新型张拉系统的加固施工工艺。
[Abstract]:At present, the application of prestressed CFRP reinforcement technology in the construction of harmful bridge reinforcement is an excellent supplement to the bridge strengthening method, which improves the deficiency of the existing bridge reinforcement methods. The prestressed CFRP technique can increase the ultimate bearing capacity of the bridge, improve the mechanical properties of the bridge, restrain the crack development, reduce the deflection of the bridge, and improve the effective utilization ratio of the carbon fiber cloth. However, there are some problems in the application of the bridge reinforcement technology in the actual bridge strengthening project, which is mainly manifested in the prestressed tensioning system of carbon fiber cloth (the existing tension equipment and anchor device are complicated to operate and occupy a large space. Major damage to the bridge itself and other problems) and construction technology. In this paper, a new tensioning system is designed and developed on the basis and principle of the existing tensioning system and combining with the characteristics of the carbon fiber cloth itself. Design and manufacture of 9 6 m long test beams for large scale experimental research, more close to the actual bridge engineering; The new tension system was used to reinforce 8 test beams with prestressed carbon fiber sheets, and 8 test beams were strengthened with single layer, double layer and three layers of carbon fiber sheets respectively. The initial prestressing force applied is 25% and 75% respectively. 8 test beams are anchored by mechanical anchoring steel plate and 8 test beams are subjected to four point bending loading with self-made reaction frame. The test results show that the new carbon fiber tensioning system can apply the initial stress to the carbon fiber cloth, and the installation and operation of the equipment is convenient and the construction efficiency is high. The reinforced concrete beams strengthened with prestressed CFRP and prestressing bolts can effectively improve the ultimate bearing capacity of the strengthened beams, increase the flexural stiffness of the strengthened beams, reduce the deflection deformation, and restrain the crack development. The carbon fiber sheet can give full play to the high strength performance and improve the mechanical properties of the bridge. Through the analysis and study of mechanical properties of RC beams strengthened with prestressed carbon fiber sheets, the ultimate bearing capacity and deflection of RC beams are analyzed and compared by theoretical calculation and experimental results. The theoretical calculation is in good agreement with the experimental results. The stress mechanism of prestressed carbon fiber cloth and pre-tightening bolt is summarized. This reinforcement technique is used to design and reinforce the K137128 channel in Dongping section of Jihe High Speed G35 Line. The effect is remarkable, and the reinforcement construction technology based on this new tension system is summarized.
【学位授予单位】：山东大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：U445.72

【参考文献】