FRP筋与EGC粘结性能试验和理论研究

发布时间：2018-03-07 07:14

  本文选题：FRP筋　切入点：ECC　出处：《东南大学》2015年硕士论文　论文类型：学位论文

【摘要】：纤维增强水泥基复合材料(Engineered Cementitious Composites简称ECC)是一种新型高性能土木工程建筑材料,具有假应变硬化和超高的韧性等特性,在体积掺量为2%的情况下,其极限拉应变约为混凝土的300倍,而极限状态下最大裂缝宽度仅为100μm左右,将其用于工程结构可大幅提升结构的承载力、延性和耗能性能。然而,FRP筋与ECC的粘结性能是保证两者协同工作的关键,是研究FRP筋增强ECC结构的重要课题之一。因此,本文对FRP筋与ECC的粘结性能进行了试验、理论以及数值模拟三个方面的研究：(1)根据FRP筋与ECC拉拔试验结果,分析了FRP筋与ECC的粘结滑移机理,和锚固长度、FRP筋的类型、FRP筋直径以及FRP筋表面形状等因素对FRP筋与ECC粘结性能的影响。结果表明：光圆和螺纹FRP筋与ECC的粘结滑移曲线分为上升段、下降段以及残余段,在残余段,粘结强度会有波动,且螺纹FRP筋与ECC的粘结滑移曲线波动幅度比光圆FRP筋的明显。CFRP筋与ECC的粘结滑移曲线上升段的斜率大于GFRP筋的,且峰值粘结应力对应的位移小于GFRP筋对应的位移,这主要是因为CFRP筋的弹性模量大于GFRP筋的弹性模量所引起的：在锚固长度一定的情况下,随着直径的增加,极限平均粘结应力减小,在直径一定的情况下,随着锚固长度的增加,极限荷载增加,而极限平均粘结应力减小；螺纹GFRP筋与ECC的粘结强度明显高于光圆GFRP筋与ECC的粘结强度,说明对FRP筋表面进行处理可以很大程度上提高FRP筋与ECC之间的粘结性能。(2)根据FRP筋表面贴应变片的拉拔试验,测得FRP筋在拉拔过程中应变的变化,计算得到试件在锚固长度范围内各测点的粘结应力以及FRP筋与ECC相对滑移的分布规律,从而得到不同位置处FRP筋与ECC粘结应力与相对滑移的关系,进而通过位置函数ψ(x)对不同位置处的粘结滑移关系进行修正,建立了考虑锚固位置影响的FRP筋与ECC的粘结滑移本构关系,为FRP筋增强ECC结构和构件的有限元分析提供基本条件。(3)结合试验得到的粘结滑移本构关系中的参数,提出三线型粘结滑移本构模型,并通过理论推导得出FRP筋应力、FRP筋与ECC的相对滑移、FRP筋表面的粘结应力、加载端的拉拔力等物理量的数学表达式,理论计算得到的加载端和自由端的荷载位移曲线与试验结果吻合较好,验证了FRP筋与ECC粘结滑移本构模型的正确性；并对粘结滑移本构关系中的各参数、FRP筋直径、锚固长度、FRP筋的弹性模量以及ECC的弹性模量等参数对最大拉拔力的影响进行了分析,最后给出了FRP筋基本锚固长度的理论计算公式。(4)采用ATENA软件对拉拔试验进行数值模拟,结果表明：数值模拟得到的加载端荷载位移曲线、FRP筋应力沿锚固方向的分布曲线以及FRP筋与ECC的粘结应力沿锚固方向的分布曲线与理论计算结果基本吻合,表明FRP筋与ECC粘结滑移本构模型的合理可行性,为后续ECC结构的研究提供新的分析手段。通过对锚固长度、FRP筋直径和最大粘结应力三个参数的分析发现：其它参数相同的情况下,随着锚固长度的增加,FRP筋与ECC的拉拔力会有很大的提高,残余荷载也对应增加；随着直径的增加,最大拉拔力和残余荷载也增加；随着最大粘结应力的增加,拉拔力增加,残余荷载保持不变。
[Abstract]:Fiber reinforced cement composite (Engineered Cementitious Composites referred to as ECC) is a new type of high performance of civil engineering materials, with pseudo strain hardening and toughness of high properties, in volume 2%, the ultimate tensile strain of concrete is about 300 times, while the maximum crack width limit state only about 100 m, which will be used in engineering structure can greatly improve the structure bearing capacity, ductility and energy dissipation performance. However, bond properties of FRP bars and ECC is the key to ensure that both the collaborative work, is one of the important topics of FRP reinforced ECC structure is enhanced. Therefore, the bond performance of FRP bar and ECC the tests were conducted on three aspects: Theory and numerical simulation (1) according to the test results of ECC FRP analysis and drawing bar, bond slip mechanism of FRP reinforced with ECC, and the anchorage length, type FRP bars, FRP bars with the diameter of And the effect of surface shape of FRP tendon and other factors on the FRP reinforcement and the bond performance of the ECC. The results show that the bond slip curve of light and thread FRP bars and ECC divided into ascending, descending and residual period, in the period of residual, the bond strength will fluctuate, and the bond slip curve slope fluctuation thread FRP bars and ECC the ratio of bond slip curve was.CFRP bars and FRP bars ECC round up section is greater than the GFRP reinforcement, displacement and the peak bond stress corresponding to the corresponding reinforcement is less than GFRP, this is mainly because the elastic modulus of CFRP bars is greater than GFRP bars caused by the anchorage length next, with the increase of the diameter limit, the average bond stress decreases in certain diameter, with the increase of the anchorage length, the ultimate load increases, and the limit of the average bond stress decreases; bond strength of reinforced ECC and GFRP were significantly higher than those of thread 鍏夊渾GFRP绛嬩笌ECC鐨勭矘缁撳己搴，

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