核心区采用纤维增强混凝土梁柱节点受剪承载力试验研究与理论分析

发布时间：2018-03-24 09:44

本文选题：纤维增强混凝土　切入点：梁柱节点　出处：《西安建筑科技大学》2014年硕士论文

【摘要】：在地震作用下，梁柱节点是保证钢筋混凝土框架结构稳定性和可靠性的关键部位。遵照“强柱弱梁”等原则按规范进行严格抗震设计的梁柱节点，其钢筋纵横交错，，施工极为困难。纤维增强混凝土(FRC)具有高韧性、高损伤容限以及变形能力好等特点，在梁柱节点核心区采用FRC材料可改善节点区的受剪延性，提高其抗震性能，并且可以适当减少核心区箍筋用量，节约钢材，方便施工。因此，研究核心区采用RFC材料梁柱节点的抗震性能及设计方法，有较好的理论意义和实用价值。为研究核心区采用FRC材料梁柱节点的受剪性能，本文对3个核心区采用FRC梁柱节点试件与1个普通混凝土梁柱节点试件进行了拟静力试验。通过改变轴压比、FRC强度，观测其在低周反复水平荷载作用下的开裂与破坏过程，研究试件的滞回特性、刚度和强度退化、能量耗散、核心区剪力-剪切变形滞回特性与梁端弯矩-曲率滞回特性等。在地震作用下，与梁柱节点相邻的梁端纵筋屈服后，纵向受力钢筋应变急剧增加，并向节点区扩展，引起节点区的主拉应变增加，从而使节点区混凝土有效压应力降低，导致节点受剪承载力降低。本文分析了由于梁纵筋屈服应变向节点区扩展而引起的节点附加应变，计算了节点区混凝土的主拉应变，并依据主拉应变确定节点区混凝土强度折减系数。在此基础上，采用斜压杆-桁架模型，建立了考虑节点变形的梁柱节点受剪承载力计算模型。根据FRC材料特性，对该计算模型进行改进，建立了核心区采用FRC材料梁柱节点受剪承载力计算模型。模型计算结果与试验结果较为吻合。
[Abstract]:Under earthquake action, Liang Zhu joint is the key part to ensure the stability and reliability of reinforced concrete frame structure. According to the principle of "strong column and weak beam" and other principles, the reinforced bar of Liang Zhu joint, which is strictly aseismic design according to the code, is crisscross. It is very difficult to construct. Fiber reinforced concrete (FRC) has the characteristics of high toughness, high damage tolerance and good deformation ability. The shear ductility and seismic performance of the joint area can be improved by using FRC material in the core area of Liang Zhu joint. And it can reduce the amount of stirrups in the core area, save steel and facilitate the construction. Therefore, it is of good theoretical significance and practical value to study the seismic performance and design method of Liang Zhu joints using RFC material in the core area. In order to study the shear behavior of Liang Zhu joints with FRC material in the core region, pseudostatic tests were carried out in three core regions using the joint specimen of FRC Liang Zhu and one specimen of common concrete joint of Liang Zhu. By changing the axial compression ratio and the strength of the joint, the shear strength of Liang Zhu joint was studied by changing the axial compression ratio. The cracking and failure processes of the specimens under low cyclic horizontal loading were observed. The hysteretic characteristics, stiffness and strength degradation, energy dissipation, shear shear deformation hysteretic behavior and torque-curvature hysteretic behavior at the end of the beam were studied. Under the earthquake action, after the longitudinal reinforcement of the beam adjacent to Liang Zhu joint yields, the strain of the longitudinal stress bar increases sharply and extends to the joint area, which causes the increase of the main tensile strain in the joint area, thus reducing the effective compressive stress of the concrete in the joint area. In this paper, the additional strain of the joint caused by the yield strain of beam longitudinal reinforcement extending to the joint zone is analyzed, and the principal tensile strain of concrete in the joint zone is calculated. According to the main tensile strain, the strength reduction coefficient of concrete in the joint area is determined. On this basis, the shear capacity calculation model of Liang Zhu joint considering joint deformation is established by using the oblique compression bar truss model. According to the characteristics of FRC material, the shear capacity of Liang Zhu joint is calculated. The model is improved and the calculation model of the shear capacity of Liang Zhu joints with FRC material in the core region is established. The results of the model are in good agreement with the experimental results.
【学位授予单位】：西安建筑科技大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TU375.4

【相似文献】