Isleem Haytham F, Abid Muhammad, Alaloul Wesam Salah, Shah Muhammad Kamal, Zeb Shayan, Musarat Muhammad Ali, Javed Muhammad Faisal, Aslam Fahid, Alabduljabbar Hisham
Department of Civil Engineering, Tsinghua University, Beijing 100084, China.
College of Aerospace and Civil Engineering, Harbin Engineering University, Harbin 150001, China.
Materials (Basel). 2021 Jun 23;14(13):3498. doi: 10.3390/ma14133498.
The majority of experimental and analytical studies on fiber-reinforced polymer (FRP) confined concrete has largely concentrated on plain (unreinforced) small-scale concrete columns, on which the efficiency of strengthening is much higher compared with large-scale columns. Although reinforced concrete (RC) columns subjected to combined axial compression and flexural loads (i.e., eccentric compression) are the most common structural elements used in practice, research on eccentrically-loaded FRP-confined rectangular RC columns has been much more limited. More specifically, the limited research has generally been concerned with small-scale RC columns, and hence, the proposed eccentric-loading stress-strain models were mainly based on the existing concentric-loading models of FRP-confined concrete columns of small scale. In the light of such demand to date, this paper is aimed at developing a mathematical model to better predict the strength of FRP-confined rectangular RC columns. The strain distribution of FRP around the circumference of the rectangular sections was investigated to propose equations for the actual rupture strain of FRP wrapped in the horizontal and vertical directions. The model was accomplished using 230 results of 155 tested specimens compiled from 19 studies available in the technical literature. The test database covers an unconfined concrete strength ranging between 9.9 and 73.1 MPa, and section's dimension ranging from 100-300 mm and 125-435 mm for the short and long sides, respectively. Other test parameters, such as aspect ratio, corner radius, internal hoop steel reinforcement, FRP wrapping layout, and number of FRP wraps were all considered in the model. The performance of the model shows a very good correlation with the test results.
大多数关于纤维增强聚合物（FRP）约束混凝土的试验和分析研究主要集中在素（无筋）小型混凝土柱上，与大型柱相比，在这些小型柱上增强效率要高得多。虽然承受轴向压缩和弯曲荷载组合（即偏心受压）的钢筋混凝土（RC）柱是实际工程中最常用的结构构件，但对FRP约束矩形RC偏心受压柱的研究却非常有限。更具体地说，有限的研究通常关注小型RC柱，因此，所提出的偏心受压应力-应变模型主要基于现有的小型FRP约束混凝土柱同心受压模型。鉴于目前的这种需求，本文旨在建立一个数学模型，以更好地预测FRP约束矩形RC柱的强度。研究了FRP在矩形截面圆周上的应变分布，以提出水平和垂直方向包裹的FRP实际破坏应变的方程。该模型使用从技术文献中19项研究汇编的155个试验试件的230个结果完成。试验数据库涵盖的无约束混凝土强度范围为9.9至73.1MPa，截面尺寸短边为100 - 300mm，长边为125 - 435mm。模型中还考虑了其他试验参数，如长宽比、角半径、内部箍筋、FRP包裹布置和FRP包裹层数。模型的性能与试验结果显示出非常好的相关性。
