Behavior and Three-Dimensional Finite Element Modeling of Circular Concrete Columns Partially Wrapped with FRP Strips

Abstract

Fiber-reinforced polymer (FRP) jacketing/wrapping has become an attractive strengthening technique for concrete columns. Wrapping an existing concrete column with continuous FRP jackets with the fiber in the jacket being oriented in the hoop direction is referred to as FRP full wrapping strengthening technique. In practice, however, strengthening concrete columns with vertically discontinuous FRP strips is also favored and this technique is referred to as FRP partial wrapping strengthening technique. Existing research has demonstrated that FRP partial wrapping strengthening technique is a promising and economical alternative to the FRP full wrapping strengthening technique. Although extensive experimental investigations have hitherto been conducted on partially FRP-confined concrete columns, the confinement mechanics of confined concrete in partially FRP-confined circular columns remains unclear. In this paper, an experimental program consisting of fifteen column specimens was conducted and the test results were presented. A reliable three-dimensional (3D) finite element (FE) approach for modeling of partially FRP-confined circular columns was established. In the proposed FE approach, an accurate plastic-damage model for concrete under multiaxial compression is employed. The accuracy of the proposed FE approach was verified by comparisons between the numerical results and the test results. Numerical results from the verified FE approach were then presented to gain an improved understanding of the behavior of confined concrete in partially FRP-confined concrete columns.

Confined Concrete in Fiber-Reinforced Polymer Partially Wrapped Square Columns: Axial Compressive Behavior and Strain Distributions by a Particle Image Velocimetry Sensing Technique

“…The focused surfaces of the specimens were sprayed with black paint while the texture was formed by white paint. Details of the test set-up can be found in Zeng et al [22]. Two Canon 5D-Mark II digital cameras were utilized to record the images of the displacement of the specimens during testing (Figure 4a).…”

“…Figure 5 shows the locations of visual strain gauges based on the PIV sensing acquisition. Note that the PIV technique has been employed to measure the strains in FRP (e.g., [22,43]) and the accuracy of the PIV sensing technique has been proved by Zeng et al [22] by applying both the PIV sensing technique and conventional strain measurement techniques to the same specimen. The stress–strain curves of the confined concrete from the both sources were close to each other.…”

“…In strengthening RC columns using the PWST, columns are generally wrapped with FRP strips/hoops (Figure 1) rather than wrapping columns with longitudinally continuous FRP jackets and the confined concrete is referred to as FRP ring-confined concrete or confined concrete in FRP partially wrapped columns hereafter. Several studies have been conducted on confined concrete in FRP partially wrapped circular columns, which demonstrate substantial enhancements in both strength and ductility of concrete in FRP partially wrapped circular columns (e.g., [17,18,19,20,21,22,23,24]).…”

Behavior of Fiber-Reinforced Polymer-Confined High-Strength Concrete under Split-Hopkinson Pressure Bar (SHPB) Impact Compression

“…The in-site wet lay-up process is often used in practice to strengthen the RC columns due to its simplicity and rapidity with respect to construction. The previous investigations prove that FRP constrains the lateral deformation of concrete, which results in three-dimensional compressive stresses in the core concrete and, subsequently, enhanced strength and ductility of FRP-confined concrete (FCC) are achieved [10][11][12][13][14][15][16][17][18][19][20][21]. FRP has also been adopted for the seismic strengthening of RC structures [22,23].…”

Axial Strength of Eccentrically Loaded FRP-Confined Short Concrete Columns

“…Fiber reinforced polymer (FRP) jacketing or confinement has been widely adopted and used in rehabilitation work on concrete structures [1][2][3][4]. The confinement can not only enhance the strength and ductility of a concrete structure [5,6] but also increase the bond between the concrete and internal steel reinforcement [7][8][9]. In addition to the structural rehabilitation, the concept of FRP confinement has also been adopted in the constructions of new structures, such as the applications of concrete filled FRP tubes [10][11][12].…”