Finite element modeling of the shear behavior of hybrid steel trussed concrete beams

The development and calibration of a three-dimensional (3D) nonlinear Finite Element (FE) model is presented with the aim of investigating the shear behavior of steel-concrete composite beams realized with a steel truss embedded into a concrete core and named Hybrid Steel Trussed-Concrete Beams (HSTCBs). The model is calibrated on the results of a reference experimental campaign of three-point bending tests on HSTCBs realized at the Laboratory of Structures of the University of Palermo. The actual behavior at the steel-concrete interface has been introduced in the model through the implementa-tion of a cohesive constitutive relationship. Furthermore, the damaged plasticity of concrete has been considered by means of the Concrete Damaged Plasticity (CDP) model with the definition of a damage variable for modeling the degradation of the constitutive behavior. The numerical simulation of the reference experimental tests allows a detailed insight of the resist-ing mechanism, giving information on the distribution of stresses in the concrete, the inclination and width of the compressed strut, the formation of plastic hinges in the web bars and the progres-sive qualitative evolution and quantitative extension of the crack pattern