Nonlinear behavior assessment of reinforced concrete frames by carbon fiber reinforced polymers under blast loading using finite element method

This paper focuses on the numerical nonlinear analysis of blast pressure wave propagation on CFRP reinforced buildings. The frequency and severity of missile attacks and terrorist operations have led to the need for building strengthened structures against these danger. The implementing of extreme and immediate explosive energy imposed to buildings needs special requirements. Also, the CFRP reinforced structures shows their ability in facing to various types of dynamic loads such as earthquakes, winds and waves. Their ability to respond to such intense loads is evaluated in this research. A fully nonlinear 2-span, 3-story ordinary and CFRP reinforced frame is modelled then subjected to three different intensity of blast loadings (explosive material’s weight). Then the nonlinear responses of models (maximum stress, displacements and maximum reflectivity pressure based on UFC code) are compared to show the performance of these structural reinforcement member. In the following, the effect of the member’s coverage rate by CFRP is investigated. The carbon fiber in CFRP composites shows the great strength and stiffness during stretching [1]. The concrete nonlinearity is explicitly implemented and its behavior is expressed using elastic damaged isotropic and tensile stresses [2]. Also, the nonlinearity of steel is modelled using the Von Misses failure criteria and the ASTM A572 [3, 4]. Finally, the blast loads are calculated based on a presented principle equation proposed by [9] according to atmosphere pressure, scaling factor and mass of blasting substance. The wave propagation of blast loads on the concrete frame was simulated using a three-dimensional model of finite element in ABAQUS/CAE 6.10-1 software. For the modelling concrete, a solid element is used from software library. The C3D8R Element is selected for properly applying concrete nonlinearity, ordinary and CFRP reinforcing. For longitudinal and transverse reinforcement of frame, the B31 two-node truss element is selected. Finally, the S4R, 4-node shell element used for modelling the CFRP parts.