FORMULATION MECHANISM AND MECHANICAL PERFORMANCE OF FUNCTIONALLY GRADED FLEXURAL CONCRETE MEMBERS
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摘要: 基于理论分析提出了一种功能梯度混凝土受弯构件,通过梯级FRP筋+钢筋混合配筋,构建同地震弯矩分布梯度相适应的构件抗弯承载能力分布梯度,使多个功能梯度段进入塑性状态,以更充分利用构件的抗震能力。功能梯度可以有效控制构件塑性的分布和发展程度,确保发生延性的破坏模式,并实现较好的损伤自恢复性。功能梯度混凝土受弯构件的变形能力大幅提高,侧向承载力增大,极限刚度降低,抗震性能显著增强。模型试验证明了功能梯度混凝土受弯构件理念的可行性及其力学效果,也验证了所提功能梯度构建方案的有效性和工程实用性。
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关键词:
- 功能梯度混凝土受弯构件 /
- 形成机制 /
- 力学性能 /
- 理论分析 /
- 模型试验
Abstract: Based on a theoretical analysis, a new functionally graded flexural concrete member (FGFCM) is proposed. Through the combined reinforcement of graded FRP bars and steel bars, the distribution gradient of the flexural load-bearing capacity along the member is adapted to the load distribution gradient. Then multiple functionally graded segments in the FGFCMs reach their plastic state, and the functional gradient is formed to more utilize the seismic capacity of the members. The distribution and development degree of the plasticity in the FGFCMs can be effectively controlled to achieve the ductile failure mode and better recoverability. The functional gradient greatly improves the deformation capacity, increases the lateral bearing capacity, reduces the ultimate stiffness, and enhances the seismic performance of the members. The model experiment proved the feasibility of the FGFCMs and their mechanical effects, and verified the effectiveness and engineering practicability of the proposed construction scheme to form the functional gradient. -
表 1 试件关键对比参数
Table 1. Key comparison parameters of specimens
试件名称 试件类型 功能梯度梯级个数 梯级序号 各梯级底端距构件固结端的距离/m 纵筋配置 配筋率/(%) 钢筋 FRP筋 试件A 传统钢筋混凝土构件 ? ? 0.00 4 1.29 ? 试件B 功能梯度构件 2个梯级 1st 0.00 4 1.29 0.98 2nd 0.70 4 1.29 ? 试件C 功能梯度构件 3个梯级 1st 0.00 10 1.29 0.45 2nd 0.50 6 1.29 0.27 3rd 0.85 4 1.29 ? 表 2 材料性能实测值
Table 2. Measured values of material performance
材料 力筋直径/
mm圆柱体抗压
强度/MPa屈服强度/
MPa极限强度/
MPa极限应变 混凝土 ? 48.5 ? ? ? 钢筋 16 ? 477.5 621.0 ? GFRP筋 14 ? ? 498.6 0.0195 CFRP筋 6 ? ? 2213.8 0.0176 表 3 试件关键力学性能
Table 3. Key mechanical performance of specimens
试件编号 形成塑性铰的
个数侧向承载力/
kN极限位移/
mm极限刚度/
(kN/mm)A 1 16.8 92.6 0.161 B 2 20.2 202.3 0.100 C 3 21.4 230.1 0.093 -
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