Numerical Analysis Of Thermal Stresses Near Interface Edges Of Strengthened Concrete Beams

Due to the inappropriate design or construction, service life, changing of the function and so on, the safety of structures could not be ensured. Therefore these structures need to be strengthened. The method strengthened with a bonded steel or carbon fiber reinforced plastics(CFRP) plate is used commonly in civil engineering.As yet, many studies have been done in strengthened concrete beams, and most of them are to consider beams under the mechanical loading. The study of the effect of thermal stresses on the strength of strengthened concrete beams is still rare. Therefore, in this paper, thermal stresses near interface edges in the concrete beams strengthened with the bonded steel and CFRP plate are analyzed numerically by the finite element method. First, the thermal stress distribution near the interface edges is obtained. Then the singularity of the thermal stresses at the interface edges is discussed. The influence of the bonded angle, length and thickness of the steel and CFRP plates as well as the elastic module of the steel plate and concrete on the thermal stresses near the interface edges is investigated.The numerical results show that the thermal stresses near the interface edges possess the singularity of ln 3r in the beams strengthened with the bonded steel and CFRP plates. The reinforce with the steel plate should be conducted at the lower temperature, while the reinforce with the CFRP plate at the higher temperature. The decrease of the bonded angle and thickness of the steel and CFRP plates as well as the reduction of the elastic module of strengthened materials can effectively reduce the value of the thermal stresses near the interface edge. The length of the steel and CFRP plates have little influence on the thermal stress near the interface edge.