the effect of confinement on concrete strength and ductility by frp jackets and angles

In this research, by examining and testing cylindrical and cubic concrete models with different strengths and drawing their stress-strain models, the effect of confine concrete on their strength and ductility was evaluated and its results showed improvement in the behavior of confined samples. for the experiment, 48 cubic specimens dimension 15 × 15 cm2 and 36 cylindrical specimens dimension 15 × 30 cm2 with resistances of 300, 350, 400 kg/cm2 were prepared to increase the accuracy, thereby endeavoring to prepare meanresults for analysis. after fabrication, the samples were curing according to standard bs-1881. then, the capping process was performed in order to apply uniform force on the concrete surfaces. wrapping was done in three ways: 1. using carbon fibers; 2. using glass fibers; 3. using angles and preheated straps.