Understanding the cracking behaviour of reinforced concrete elements subjected to the restraint of imposed strains (EPSRC DTP)

In design, the minimum required amount of secondary (horizontal) reinforcement in members such as retaining walls, bridge abutments and walls of reservoirs is often controlled by early thermal cracking, which results from the restraint of imposed thermal and shrinkage strains. Two types of external restraint can typically be found; end restraint and edge (base) restraint. In practice, the restraint is often a combination of these two forms that occur simultaneously when (for instance, in terms of a wall) a new section of concrete is cast between pre-existing concrete sections and onto pre-existing concrete base. At the base, edge restraint will dominate, while up the wall away from the base, end restraint becomes more influential.

This is an experimentally based project (requiring FE analysis for validation and parameter study), that will investigate the effect of external restraint on the cracking behaviour of concrete elements undergoing imposed strains. The data and subsequent design guidance (which will be used to update all relevant design codes) will finally allow designers to negate the significant serviceability issues present due to this phenomenon, which commonly plague RC structures.