预应力CFRP板加固梁桥的效果监测与研究

发布时间：2018-04-21 04:23

本文选题：预应力CFRP板 + 长标距FBG　；参考：《东南大学》2016年硕士论文

【摘要】：预应力CFRP(Carbon Fiber Reinforced Polymer Plate)板快速加固桥梁技术是近年来发展的桥梁结构新型加固技术,然而目前尚缺乏预应力CFRP预应力损失的有效监测和评价方法。针对该现状,本文首次采用长标距光纤光栅(FBG)传感技术监测预应力损失,通过系列试验和有限元分析综合研究了预应力CFRP板加固混凝土结构的力学性能及其预应力损失特征,提出了相应的预应力损失监测和评价方法。最后,以汾灌高速新沭河大桥预应力CFRP板加固工程为背景,通过长期预应力损失监测和有限元软件建模验证了基于长标距FBG传感的预应力损失监测和评价方法的有效性。主要研究内容及结论如下：(1)通过对体外预应力CFRP板加固混凝土梁的CFRP预应力损失以及施工过程与使用过程中混凝土受拉与受压区应力进行理论分析,分析了预应力损失的几方面主要原因,并推导了相应的预应力损失公式。同时,推导了在加固施工过程中和加固后正常使用中的混凝土最大拉压应力计算公式。(2)本文开展试验梁实验研究预应力CFRP加固技术。采用用分布式长标距FBG传感技术实时监测了预应力CFRP板加固实验梁张拉过程及完成后的CFRP板、混凝土以及钢筋的应变变化状况,50天预应力损失趋于稳定并小于5%,表明CFRP板可与混凝土梁共同工作,满足预期要求；同时,开展了四点弯静载和疲劳试验,结果表明：预应力CFRP板具有良好的加固效果,混凝土的初始开裂荷载和承载力分别提高60%和30%以上,锚固系统具有良好的抗疲劳性能。建立ANSYS模型对试验梁进行分析,张拉过程中各部分应变变化与试验梁实测数据基本一致,表明试验梁张拉过程满足加固要求。试验梁分别使用力卡锚固系统和刚性自锁式锚固系统两种系统,对CFRP板施加预应力进行平行对比研究,得出力卡锚固系统张拉完成后达到了更好的加固效果。(3)采用长标距FBG传感器对新沭河桥预应力CFRP板加固工程进行监测,研究了加固中CFRP板及混凝土的应变变化,以及预应力CFRP板长期应变损失。结果表明,加固后箱梁跨中混凝土压应力增量为0.42MPa左右,在有限元计算值0.25～0.60MPa范围内；张拉后CFRP板应变约为7500με,预应力短期损失约为张拉控制应力的3%,满足加固设计要求；通过对预应力CFRP板长期预应力监测,预应力CFRP板的长期预应力损失率约为5%；且随时间推移,预应力损失率逐渐减少,3个月后基本不再变化。综上表明,预应力CFRP板加固技术运用于实桥工程具有较好的加固效果。
[Abstract]:Prestressed CFRP (Carbon Fiber Reinforced Polymer Plate) plate rapid reinforcement of bridge technology is a new bridge reinforcement technology developed in recent years. However, there is still a lack of effective monitoring and evaluation method for the loss of prestressed CFRP prestress at present. For the first time, this paper uses long standard distance fiber grating (FBG) sensing technology to monitor prestress for the first time. Loss, through a series of experiments and finite element analysis, the mechanical properties of prestressed CFRP reinforced concrete structure and the characteristics of prestress loss are synthetically studied, and the corresponding monitoring and evaluation methods of prestress loss are put forward. Finally, the long-term prestress loss supervision is carried out in the background of the prestressed CFRP plate consolidation project of the Fenshui high speed Shishu River Bridge. The measurement and finite element software modeling verifies the effectiveness of the prestress loss monitoring and evaluation method based on long standard distance FBG sensing. The main contents and conclusions are as follows: (1) the stress loss of concrete beams strengthened by external prestressing CFRP plate and the stress in the tension and compression zone of concrete during the construction process and the application process are carried out. In theory analysis, the main reasons of prestress loss are analyzed, and the corresponding formula of prestress loss is derived. At the same time, the formula for calculating the maximum tensile stress of concrete in normal use of reinforcement construction and after reinforcement is derived. (2) in this paper, experimental beam experiment is carried out to study prestressed CFRP reinforcement technology. The standard distance FBG sensing technology is used to monitor the tension process of the prestressed CFRP plate reinforced experimental beam and the strain changes of the CFRP board, concrete and the steel bar after completion. The 50 day prestress loss tends to be stable and less than 5%. It shows that the CFRP board can work with the concrete beam to meet the expected requirements. At the same time, the static load and fatigue test of four points have been carried out. The results show that the prestressed CFRP plate has good reinforcement effect, the initial cracking load and the bearing capacity of the concrete are increased by 60% and 30% respectively. The anchorage system has good fatigue resistance. The ANSYS model is established to analyze the test beam. The changes of each part in the tensioning process are basically consistent with the experimental data of the test beams. The tensile process of the test beam meets the requirements of reinforcement. The test beams are used two systems of the force card anchorage system and the rigid self locking anchorage system respectively, and the CFRP board is prestressing in parallel. After the tension card anchorage system has been completed, the strengthening effect has been achieved. (3) the long standard distance FBG sensor is used for the prestressed CFR of the new Shuhe River Bridge. The P plate reinforcement project is monitored, and the strain changes of the CFRP plate and concrete in the reinforcement and the long-term strain loss of the prestressed CFRP board are studied. The results show that the increment of the compressive stress of the concrete in the span of the box girder is about 0.42MPa, and the calculation value is 0.25 to 0.60MPa in the finite element. The strain of the CFRP plate after tension is about 7500 um, and the prestress is short term. The loss is about 3% of the tension control stress, which meets the requirements of the reinforcement design. By monitoring the long-term prestress of the prestressed CFRP plate, the long-term prestress loss rate of the prestressing CFRP plate is about 5%, and the loss rate of the prestress decreases gradually with time, and is basically no longer changed after 3 months. It is shown that the prestressed CFRP plate reinforcement technology is applied to the real bridge. The project has good reinforcement effect.

【学位授予单位】：东南大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：U445.72

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