Effective stiffness of reinforced concrete section with lightweight blocks infill

Abstract

An experimental program has been conducted to explore the potential use of the developed Lightweight Sandwich Reinforced Concrete LSRC section as beam members. The Autoclaved Aerated Concrete(AAC) is used as infill in the LSRC section. Based on the tested beams, the flexural and shear strengths of LSRC beams are found to be comparable with the strengths of the solid beams having identical height. ANSYS 12.1 was employed to develop nonlinear finite element models of LSRC beams. The beams modelled with ANSYS followed the same trend as the actual beam in the elastic range, however after the first cracking the loss of stiffness in ANSYS model caused greater deflection compared to the actual beam. It is obvious that after the first crack the stiffness of sandwich section decrease because the lower elastic modulus of the combined materials. Another investigation is made to compare the behaviour of an LSRC beam with a hollow beam subjected to flexure failure. It is found that the stiffness decreases along with the decrease of the cross section of concrete. The results of the deflections predicted by ANSYS are comparable with the deflection based on the stiffness equation provided by Australian design code.