Experimental Study and FE Simulation of Deformation of Steel-encased Concrete T-Composite Beams Subjected to Torsion

In order to study the deformation behavior of steel-encased concrete T-composite beam under pure torsion action,five full size cantilever specimens with different stirrup ratio were designed.According to experimental study on the torsion performance of cantilever composite beams,a set of curves related torque with torsion angle per unit length was derived.Nonlinear finite element analysis about torsion performance of composite beams was conducted based on finite element analysis software-ANSYS,and the stress nephogram of steel-encased concrete beam in the limit stage was gained.The torsion stiffness change of composite beam during entire loading process was analyzed based on experimental and FE results.Based on current concrete design criterion,a torsion stiffness formula for composite beams from the cracking stage to the limit stage was proposed for design reference.The results obtained from FE model and above-mentioned formula are proved to be in good agreement with the experimental data.