CFRP-螺旋箍筋复合约束混凝土抗冲击性能研究

发布时间：2018-03-30 10:20

  本文选题：CFRP　切入点：螺旋箍筋　出处：《湖南大学》2015年硕士论文

【摘要】：对混凝土施加约束可以有效改善混凝土的材料性能。相比素混凝土,约束混凝土在抗压强度和变形能力上有显著提高,从而使构件具有更好的性能和抗震能力。通常对混凝土施加约束的方法有FRP约束、钢管约束、箍筋约束等,不同的约束方式会导致构件不同的受力特点。因此对比不同约束形式的受力性能,探索更加有效的约束方式具有较大的工程意义。本文首先讨论了FRP约束混凝土构件和螺旋箍筋约束混凝土构件的性能特点,在此基础上提出了FRP-螺旋箍筋复合约束混凝土构件,此种约束能发挥FRP和螺旋箍筋材料的特点。本文主要工作如下:(1)本文设计了30组共240个FRP试件,进行动态拉伸试验。得到了试件的应力-应变曲线,并用高速相机记录了试件破坏全过程。分析了温度和应变率对其强度和韧性的影响,对比了各种条件下的破坏形态,并通过Weibull分析总结其力学性能变化规律。(2)在FRP材性试验的基础上,选用CFRP进行后续复合约束混凝土抗冲击性能试验研究。设计了8组共24个约束试件,包括2组CFRP单独约束,2组螺旋箍筋单独约束和4组CFRP-螺旋箍筋复合约束试件。记录了试件冲击力时程曲线,应变时程曲线,并用高速相机进行了拍摄。(3)总结了各组试件的冲击力时程曲线和应变时程曲线的特点,对比了各组试件的破坏形态,探讨CFRP层数、螺旋箍筋间距、冲击能量和锤重等参数对试件抗冲击性能的影响。(4)采用ANSYS/LS-DYNA软件对试验过程进行模拟,模拟结果和试验较为吻合,在此基础上,对冲击过程中能量的变化规律进行了探讨。本文研究结果表明,FRP具有应变率效应,拉伸强度和韧性随着应变率的提高而提高;拉伸强度对温度不敏感,只有到达100℃才有明显降低;与常温相比,温度的改变会造成韧性的下降。CFRP-螺旋箍筋复合约束混凝土试件能有效发挥两种材料的优势,使试件具有更高的抗压强度和更好的耗能能力。约束形式的改变对试件力学性能影响较大,冲击能量和锤头重量对抗冲击承载力影响不显著。
[Abstract]:The material properties of concrete can be effectively improved by imposing restraint on concrete. Compared with plain concrete, confined concrete has a significant increase in compressive strength and deformation ability. In order to make the members have better performance and anti-seismic ability. Usually the methods of imposing constraints on concrete include FRP constraint, steel pipe constraint, stirrups constraint, etc. Different constraints will lead to different mechanical characteristics of the member. It is of great engineering significance to explore more effective restraint modes. In this paper, the performance characteristics of FRP confined concrete members and spiral stirrups confined concrete members are discussed, and on this basis, the FRP-spiral stirrups composite confined concrete members are proposed. This constraint can take advantage of the characteristics of FRP and spiral stirrups. The main work of this paper is as follows: (1) in this paper, 30 groups of 240 FRP specimens are designed for dynamic tensile tests. The stress-strain curves of the specimens are obtained. The whole failure process of the specimen was recorded with a high-speed camera. The effects of temperature and strain rate on the strength and toughness of the specimen were analyzed, and the failure patterns under various conditions were compared. On the basis of FRP properties test, CFRP was selected to study the impact resistance of concrete with compound confinement. Eight groups of 24 confined concrete specimens were designed. It consists of two groups of CFRP alone and two groups of spiral stirrups and four groups of CFRP-helical stirrups composite confined specimens. The time history curve of impact force and strain time history curve of the specimen are recorded. The characteristics of impact time history curve and strain history curve of each group of specimens are summarized, the failure patterns of each group are compared, the number of CFRP layers and the space of spiral stirrups are discussed. The effect of parameters such as impact energy and hammer weight on the impact resistance of the specimen is simulated by ANSYS/LS-DYNA software. The simulation results are in good agreement with the test results. The change of energy during impact is discussed. The results show that FRP has strain rate effect, tensile strength and toughness increase with the increase of strain rate, tensile strength is not sensitive to temperature, When the temperature reaches 100 鈩，

本文编号：1685498