Comparative analysis and critical issues of the main constitutive laws for concrete elements confined with FRP

This paper presents and compares the results of an analysis dealing with various constitutive laws for reinforced concrete elements confined with FRP. One of the main problems of such constitutive laws is their dependence not only on concrete class, fiber type and wrapping’s number of sheets, but on cross-section’s size too. Because of the great number of parameters involved in the different analyzed constitutive laws, it is very difficult to predict the effects both in terms of ultimate strength and/or ultimate strain of the different assumptions and calibration option. A comparative analysis is herein presented aiming to point out the “critical issues” affecting the constitutive laws.