ABSTRACT
Based on the framework of mechanics of composite materials and the theory of elastic-plasticity, an analytical solution of elastic-plastic responses is developed for a composite system of concrete filled CFRP-steel tube. Under a uni-axial compressive loading the average stresses of 3 constituent materials and the overall effective secant Young’s modulus are derived. It is shown that the initial yield stress and ultimate stress of the system is enhanced significantly by bonding with CFRP comparing to the traditional concrete filled steel tube. Also an explicit equation is provided to express the connecting condition of steel tube and concrete core, which shows a remarkable improvement for the confinement of steel tube to concrete.
