Predicting the influence of restraint on reinforced concrete panels using finite element models developed from experimental data

Externally restraining volume changes of concrete, that is, 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 a 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 behavior under edge restraint too. Researchers have identified that the mechanisms of cracking associated with edge and end restraints are quite different. To this purpose, findings from an experimental investigation aiming to understand the behavior of edge restrained RC walls were utilized to validate a finite element (FE) model. Subsequently, this FE model was used to parametrically study walls having different aspect ratios and subjected to different forms of restraint. Cracking patterns, widths, and extent appeared to greatly depend on the type of restraint and wall aspect ratio. The influence of combined restraint, for instance, was found to be more significant in walls with aspect ratio less than 4. The study provides clear evidence on why similar studies, are needed to support engineers in designing against cracking due to restraints.