Investigation of the influence of external edge restraint on reinforced concrete walls

Abstract

Abstract. Externally restraining volume changes of concrete, i.e., thermal effects and shrinkage, may result in tensile stresses and eventually cracking. Such cracking risk is controlled / mitigated by the provision of steel reinforcement, which presumes correct understanding of the cracking patterns under different types of restraint conditions. Reinforced concrete (RC) members may be restrained at their edges or end, or in many cases a combination of the two. Existing guidance on the subject is mostly based on end restrained members, however it is applied to predict the behaviour under edge restraint too. Researchers have identified that the mechanisms of cracking associated to edge and end restraints are quite different. To this purpose, findings from an experimental investigation aiming to understand the behaviour of edge restrained RC walls were utilized to validate a finite element (FE) model. Subsequently, this FE model was used to study the edge restrained walls having different aspect ratios. Cracking patterns, widths and extent appeared to greatly depend on the wall aspect ratio. The study provides clear evidence on why similar studies related to all forms of restraint are needed to support engineers in designing against cracking due to restraints.