Numerical Simulation of Steel Reinforced Lightweight Aggregate Concrete Beams Based on Analysis of Push-out Test

Abstract

To study the influence of bond-slip on the numerical simulation of steel reinforced lightweight concrete(SRLC) members, the push-out test and finite element analysis are carried out first, and then the nonlinear finite element simulation of SRLC beams is conducted. The calculated results are compared with the experimental results. Four factors as the concrete protective cover thickness, stirrup ratio, concrete strength and anchorage length of section steel are considered in test. The constitutive relation of interface bonding slip between the section steel and light concrete is introduced in the finite element analysis based on the test results. Finite element analysis of push-out specimens results indicate that the normal stress of the section steel is the same on the same cross section and the stress gradient gradually decreases from the loading end to the free end. Specimens with equivalent restraint coefficient γe less than 0.01 will be subjected to split failure and those specimens with the coefficient γe greater than or equal to 0.01 will be subjected to push-off failure. The bearing capacity and slip value obtained by finite element computation is consistent with experiment results. The stress distribution, crack shape and load-deflection curve are analyzed in numerical simulation of SRLC beams. Influence factors involving shear span ratio and position of section steel are considered．Analysis results show that the mechanical properties of the SRLC beams are similar with that of the steel reinforced normal concrete (SRNC)beams. Diagonal shear failure are gradually transformed into flexural failure with the shear span ratio increasing. Load- deflection curve is obviously divided into three stages. Finite analysis results considering the slip between section steel and concrete agree well with the test results, while the capacity and stiffness without considering the slip are bigger than the experimental values.