CFRP板条嵌入式加固RC梁受剪性能研究

发布时间：2018-07-26 20:56

【摘要】：纤维增强复合材料(Fiber Reinforced Polymer/Plastic,简称FRP)以其轻质、绝缘、机械强度高、回收利用少、耐腐蚀等优点在土木工程加固领域得到了广泛的应用。嵌入式FRP加固技术是近年来由国外学者提出的一种新兴的加固方法,即在混凝土结构构件表层开槽,将FRP板条或是筋材放入其中,用胶结材料将二者粘结以达到共同受力的目的。目前,嵌入式FRP加固技术主要集中在抗弯方面的研究,对于抗剪加固仍有诸多问题有待于解决。本文通过对已有试验数据的四根梁(一根对比梁和三根试验梁)建立有限元模型,将模拟结果与试验数据进行比较分析,以验证有限元模型的准确性。本文基于CFRP板条加固量相同的前提下,建立2根对比梁和12根加固梁,以CFRP板条嵌入角度、剪跨比、槽间距为研究参数,对加固梁的破坏模式、抗剪承载力、刚度、箍筋和CFRP的应变展开分析。根据已有嵌入式加固FRP发生胶层剥离时有效应变的研究成果,基于桁架模型推导出嵌入式CFRP加固RC梁的抗剪承载力公式。通过有限元分析,基于CFRP板条加固量相同时,不同加固方式下加固梁的抗剪承载力和刚度均得到不同程度的提高,但对加固梁的开裂荷载提高幅度不是特别明显。相同的开槽方式下,45°嵌入角的加固方式抗剪承载力提高幅度最大,60°角加固效果次之,90°角加固效果最差;剪跨比越大,加固效果越明显;采用多槽多板的加固方式,CFRP的利用率更高,承载力提高幅度更大。通过箍筋、CFRP的荷载-应变曲线可以很好的反映出斜裂缝的开裂荷载,在荷载加载初期,混凝土、箍筋、FRP板条共同工作,此时CFRP板条的作用不是很明显,趋于弹性阶段。当斜裂缝出现后,混凝土的贡献减弱,此时箍筋、CFRP正式进入工作状态,应变急剧增大。通过对本文所提出的嵌入式CFRP加固梁抗剪承载力计算公式的计算值与模拟值的比较,发现二者数据较为吻合。
[Abstract]:Fiber reinforced composites (Fiber Reinforced Polymer / plastic (FRP) has been widely used in the field of civil engineering reinforcement because of its advantages of light weight, high insulation, high mechanical strength, less recycling, corrosion resistance and so on. Embedded FRP reinforcement technology is a new reinforcement method put forward by foreign scholars in recent years, that is, slotted in the surface of concrete structural members, FRP slab or reinforcement is put into it. The two materials are bonded to achieve the purpose of common force. At present, the embedded FRP reinforcement technology mainly focuses on the research of bending resistance, and there are still many problems to be solved for shear reinforcement. In this paper, the finite element model of four beams (one contrast beam and three test beam) with available test data is established, and the simulation results are compared with the experimental data to verify the accuracy of the finite element model. Based on the same reinforcement quantity of CFRP slab, two contrast beams and 12 strengthened beams are established in this paper. The failure mode, shear bearing capacity and stiffness of strengthened beams are studied by using CFRP slab embedding angle, shear span ratio and slot spacing as parameters. Strain expansion analysis of stirrups and CFRP. Based on the existing research results of effective strain of FRP strengthened with embedded CFRP during the exfoliation of rubber layer, the formula of shear capacity of RC beams strengthened by embedded CFRP is derived based on the truss model. Based on the finite element analysis, the shear bearing capacity and stiffness of the beams strengthened with the same amount of CFRP slab are improved in different degrees, but the increase of the crack load of the strengthened beams is not particularly obvious. Under the same slotted mode, the shear bearing capacity of the reinforcement method with 45 掳embedded angle is the highest, and the effect of 90 掳angle reinforcement is the worst, and the reinforcement effect is more obvious with the increase of shear span ratio. The efficiency of CFRP is higher and the bearing capacity of CFRP is higher. Through the load-strain curve of stirrups, the cracking load of inclined cracks can be well reflected. In the early stage of loading, concrete and stirrups are working together. At this time, the action of CFRP slab is not obvious and tends to elastic stage. When the oblique crack appears, the contribution of concrete weakens, and the stirrups CFRP formally enters the working state, and the strain increases sharply. By comparing the calculated values of shear bearing capacity of embedded CFRP strengthened beams with the simulated values, it is found that the two data are in good agreement with each other.
【学位授予单位】：吉林建筑大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU375.1

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