RESTRAINED SHRINKAGE IN REPAIRED REINFORCED-CONCRETE ELEMENTS

This paper describes an analytical model of restrained shrinkage in repaired reinforced concrete elements. The results of analysis and test show that the effect of restrained shrinkage on the serviceability of the repaired element is quite significant. The computer based analysis proposed can be applied to predict progressive crack development in a repair material subjected to restrained shrinkage during construction. The properties of repair materials, such as ultimate strain in tension, creep coefficient and free shrinkage, are major factors influencing the performance of structural repairs. Restrained shrinkage is related to the stiffness of a repaired section of known structure. The effect of moment redistribution on restrained shrinkage is significant in elements of indeterminate structure. The stress and strain caused by restrained shrinkage in elements of indeterminate structure are higher than in elements of known structure, and an example given in this paper shows an increase in strain of about 30%.