Modeling of Fiber Reinforced Polymer confined concrete cylinders

Fiber Reinforced Polymer (FRP) confined concrete columns have been developed for new construction and rebuilding of concrete piers/piles in engineering structures. Design of these FRP confined concrete columns requires an accurate estimate of the performance enhancement due to the confinement mechanism. Therefore, the key is to develop a confinement model, a model that relates the confined concrete strength with the unconfined concrete strength and the confining pressure provided by the FRP. Due to its closed-form expression and ease of application, design-oriented confinement models predominate in designing FRP confined concrete columns. Design oriented models are directly based on the interpretation of experimental results. Each existing design oriented model is based on a certain range of test database and is accurate in predicting the results within its respective considered range. All the models are based on limited database. In the present research, an attempt was made to expand the test database with larger range. A 3-D finite element model of FRP confined concrete column was developed using ANSYS and was validated by published experimental results available in the literature. Based on the FEA results, a test data base was developed taking into account all the possible ranges of the design parameters which affect the confined concrete strength. Analyses of the test database revealed that the confinement effectiveness depends on thickness, hoop tensile strength, modulus of elasticity of the FRP and unconfined concrete strength and behaves nonlinearly with each of them. Therefore, in the present study the main emphasis was to explore a possible approach for a design oriented confinement model which considers this nonlinear relation between the confinement effectiveness and the design parameters