海洋潮汐作用下纤维筋与混凝土粘结性能试验研究

发布时间：2018-04-13 17:47

本文选题：FRP筋 + 夹片式锚具　；参考：《浙江大学》2013年硕士论文

【摘要】：混凝土与FRP筋的粘结将直接影响其长期工作性能,现阶段相关试验研究主要针对FRP筋的类型、FRP筋的粘结长度、FRP筋的直径、FRP筋的表面形状及混凝土强度研究FRP与混凝土长期粘结性能变化,但是针对外部环境作用,特别是海水盐度及潮汐循环作用对粘结性能影响却一直没有得到重视。近海和沿海区域的高侵蚀环境导致钢筋混凝土耐久性退化严重,成为FRP筋代替钢筋的重要原因之一。尽管现阶段针对FRP筋的耐久性试验考虑了侵蚀环境的影响,但侵蚀性海洋环境下FRP筋与混凝土粘结性能尚未见报道。相对于海洋大气环境和海洋水下环境,海洋潮汐环境的干湿交替作用将对混凝土孔隙结构和FRP筋的耐久性能和两者之间的粘结退化带来更为显著的影响。 1.基于FRP筋夹片式锚具试验研究获取的极限承载力、滑移值等测试信息建立3D有限元模型,采用数值模拟方法针对锚固体系开展非线性受力分析,模型分析与基准试验在滑移动态演变过程、失效形态和测试数值上均具有高度的吻合率和精度。鉴于试验规模的局限性,试验获取的测试参数无法满足FRP筋锚具设计的需要,利用有限元进行夹片式锚具受力分析,讨论了锚环锥角、夹片与锚环之间的角度差、铝套管厚度、夹片预紧力、夹片与锚环之间的初始接触位置、锚具长度等参数对锚具性能的影响,通过数值分析确定上述参数的推荐取值范围,对FRP筋夹片式锚具设计及改进提供参考和借鉴。 2.本试验以工程调查的海水盐度制作海水样本溶液,通过添加不同盐度的溶液制作了74个FRP筋拉拔试件和36个立方体伴随试块,以一定浓度盐溶液干湿交替对混凝土粘结构件进行海洋潮汐环境作用模拟,测试经历不同潮汐循环下的混凝土粘结试件的拉拔曲线,旨在获取潮汐环境下FRP筋与混凝土粘结退化规律。 3.在本文试验以及已有试验研究的基础上,提出了BFRP筋与混凝土粘结滑移退化理论模型,并与试验所得粘结滑移曲线进行比较,模型曲线与试验曲线吻合良好。同时利用ANSYS程序对BFRP筋与混凝土拉拔试件进行有限元模拟,并系统总结出了考虑粘结滑移的BFRP筋与混凝土构件的ANSYS程序有限元分析建模和计算方法。采用ANSYS有限元软件对试件进行数值模拟,将试验曲线与数值模拟曲线进行对比,并对模型中BFRP筋的应力应变进行分析研究,验证ANSYS软件数值模拟结果的正确性。
[Abstract]:The bond between concrete and FRP bars will directly affect its long-term working performance.At present, the research on the long-term bond behavior between FRP and concrete is mainly focused on the bond length and the surface shape of FRP tendons and the strength of concrete, but the effect of external environment on the bond behavior between FRP and concrete is also discussed.In particular, the effect of seawater salinity and tidal cycle on bond properties has been neglected.The durability of reinforced concrete is degraded seriously by high erosion environment in offshore and coastal areas, which is one of the important reasons why FRP bars replace steel bars.Although the effect of erosion environment is taken into account in the durability test of FRP tendons at present, the bond properties between FRP tendons and concrete in erosive marine environment have not been reported.Compared with the marine atmospheric environment and the marine underwater environment, the interaction of dry and wet in the marine tidal environment will have a more significant effect on the durability of concrete pore structure and the durability of FRP bars and the bond degradation between them.1.A 3D finite element model is established based on the testing information of ultimate bearing capacity and slip value obtained from the experimental study of FRP reinforcement clamped Anchorage, and the nonlinear force analysis of the Anchorage system is carried out by numerical simulation method.The model analysis and the benchmark test have a high coincidence rate and precision in the dynamic evolution of slip, failure form and testing value.In view of the limitation of the scale of the test, the test parameters obtained from the test can not meet the needs of the design of the anchor with FRP bars. The stress analysis of the clamped Anchorage is carried out by using finite element method. The cone angle of the anchor ring, the angle difference between the clamp and the anchor ring, and the thickness of the aluminum casing are discussed.The influence of the pretightening force, the initial contact position between the clip and the anchor ring, the length of the anchor and other parameters on the performance of the anchor is obtained. The recommended range of the above parameters is determined by numerical analysis.It provides reference for the design and improvement of FRP clip Anchorage.2.In this experiment, the seawater sample solution was made from the seawater salinity investigated by engineering, and 74 FRP bar drawing specimens and 36 cube concomitant test pieces were made by adding different salinity solutions.The effect of ocean tide on concrete adhesive structure was simulated by alternating dry-wet with a certain concentration of salt solution, and the drawing curves of concrete bonded specimens under different tidal cycles were tested.The purpose of this paper is to obtain the law of bond degradation between FRP bars and concrete in tidal environment.3.On the basis of the experiments in this paper and the existing experimental studies, a theoretical model of bond-slip degradation between BFRP bars and concrete is proposed, and compared with the bond-slip curves obtained from the tests, the model curves are in good agreement with the experimental curves.At the same time, the finite element analysis method of BFRP bar and concrete drawing specimen is simulated by ANSYS program, and the ANSYS program finite element analysis modeling and calculation method of BFRP bar and concrete member considering bond-slip are summarized systematically.The ANSYS finite element software was used to simulate the specimen. The test curve was compared with the numerical simulation curve, and the stress and strain of the BFRP bars in the model were analyzed and studied to verify the correctness of the numerical simulation results of the ANSYS software.
【学位授予单位】：浙江大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：TU377

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