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

Junjie Zeng,Yongchang Guo,Lijuan Li,Weipeng Chen

doi:10.3390/polym10030253

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.

Highlights

Over the past two decades, fiber-reinforced polymer (FRP) has become a favorite material for the strengthening of existing concrete columns
Test results based on the 15 FRP-strengthened cylindrical concrete column partially wrapped
Test results based on the 15 FRP-strengthened cylindrical concrete column partially wrapped with FRP strips have been presented in this paper

Summary

Introduction

Over the past two decades, fiber-reinforced polymer (FRP) has become a favorite material for the strengthening of existing concrete columns. The FRP strengthening technique for a concrete column is predominantly referred to as FRP full wrapping strengthening technique in which an existing deteriorated concrete column is fully wrapped with FRP jacket along the height of the column (Figure 1a). The resulting column of this strengthening technique is referred to as a fully FRP-confined concrete column. Existing research has demonstrated that the compressive strength and ductility of circular columns fully wrapped with FRP jackets are substantially enhanced [1,2,3,4,5,6,7,8,9,10,11,12,13,14]. Most studies related to FRP-confined concrete columns are on fully FRP-confined concrete columns, partially FRP-confined concrete columns have been demonstrated to possess adequate increase in strength and excellent increase in ductility compared

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Results

Conclusion