Elasto-plastic Bending Behaviors of Steel Fiber Reinforced Expanded-shale Lightweight Concrete Beams Analyzed by Nonlinear Finite-element Method

Abstract

This paper focuses on the study of elasto-plastic bending behaviors of steel fiber reinforced expanded-shale lightweight concrete (SFRELC) T-beams by using the nonlinear finite-element method. The nonlinear finite-element model of T-beams was built with the rational constitutive models of SFRELC, steel bars and their bond-slip. The finite-element dimension was taken as one-third of average crack spacing to reflect the actual crack distribution and crushed compression zone. The loading procedure was controlled by displacement to perform the complete loading procedure. The convergence tolerance was enlarged with the adjusted loading substep to solve non-convergent issue in the elasto-plastic portion. The numerical analysis and experimental work were performed for five reinforced SFRELC T-beams with a varying volume fraction of steel fiber from zero to 2.0%. Results indicated that except for about 22% higher cracking moment, the numerical results agreed well to the experimental in the bearing capacity, the strains of SFRELC and longitudinal tensile steel bars, the complete load-deflection curve and the flexural ductility. Identical crack distribution and failure pattern was given out. The total width of cracks computed by the displacement difference between the longitudinal steel bar and the SFRELC is almost equal to the sum of crack width measured within pure bending segment. This confirms the adaptability of the numerical model to be used for the virtual-test to investigate the complete bending performance of reinforced SFRELC T-beams.