Stiffness-based design-oriented compressive stress-strain model for large-rupture-strain (LRS) FRP-confined concrete
Stiffness-based design-oriented compressive stress-strain model for large-rupture-strain (LRS) FRP-confined concrete
复制标题
基于刚度设计的大断裂应变 (LRS) FRP 约束混凝土的压缩应力应变模型
DOI：
10.1016/j.compstruct.2019.110953
复制
发表时间：
2019-09-01
影响因子：
6.3
通讯作者：
Mei, Shi-Jie
中科院分区：
文献类型：
--
作者：
Bai, Yu-Lei;Dai, Jian-Guo;Mei, Shi-Jie
大断裂应变纤维增强聚合物（LRS FRP）（例如，具有大于5%的伸长率）为混凝土柱的抗震加固提供了理想的限制。现有的FRP约束混凝土设计导向模型大多定义了轴向应力-应变曲线的斜率（即，轴向刚度）作为FRP断裂应变的函数。因此，相同套壳刚度但不同破裂应变的FRP约束混凝土通常会导致不同的轴向刚度，这与实验观察相反。对于LRS FRP约束混凝土，轴向刚度的微小偏差可能会导致其极限状态预测的显着误差。因此，这里开发了一个面向设计的模型，使用护套刚度而不是其断裂应变来定义轴向刚度。26 LRS FRP约束圆形混凝土圆筒进行了测试，并添加到数据库中的36个现有的标本。然后，现有的横向到轴向应变（膨胀）的关系升级的基础上，上述数据库和数据库上的113个传统的FRP约束混凝土圆筒。一个三重的方法来定义的LRS FRP约束混凝土作为一个功能的夹克刚度的全范围应力-应变关系。建议的刚度为基础的设计导向模型预测软化和硬化行为，适用于传统和LRS FRP约束混凝土柱。
Large rupture strain fiber-reinforced polymers (LRS FRPs) (e.g., with an elongation larger than 5%) provide ideal confinement for seismic retrofit of concrete columns. Most of existing design-oriented models for FRP-confined concrete define the slope of axial stress-strain curve (i.e., axial stiffness) as a function of FRP's rupture strain. Consequently, concrete confined with FRP of the same jacket stiffness but different rupture strains usually lead to different axial stiffnesses, which is contrary to the experimental observations. For LRS FRP-confined concrete a slight deviation in the axial stiffness might cause significant error in predicting its ultimate state. Therefore, a design-oriented model is developed here to define axial stiffness using the jacket stiffness rather than its rupture strain. 26 LRS FRP-confined circular concrete cylinders are tested and added to a database of 36 existing specimens. Then an existing lateral-to-axial strain (dilation) relationship is upgraded based on the above database and a database on 113 conventional FRP-confined concrete cylinders. A three-fold approach is employed to define the full-range stress-strain relation of LRS FRP-confined concrete as a function of jacket stiffness. The proposed stiffness-based design-oriented model predicts both softening and hardening behaviors and is applicable to both conventional and LRS FRP-confined concrete columns.