Degree of restraint concept in analysis of early-age stresses in concrete walls

The degree of restraint is a useful concept for characterisation of early-age thermal-shrinkage stresses occurring in externally-restrained concrete elements such as walls. It can be used not only in manual calculations, but also in numerical analysis to determine the values and distribution of stresses in walls. The issues that must be addressed while defining the degree of restraint of the wall include the stiffness of the restraining body (e.g. foundation), translational and rotational restraints, influence of the construction sequence and support conditions. These issues are discussed in the paper. For the purpose of the study a numerical model is proposed which takes into account sequential casting and interaction between early-age structure and founding soil. The results of the study point out the factors that need be taken into account when modelling structural behaviour of early-age walls for proper determination of the expected stresses.