Shrinkage Effect on Beams Strengthened with Additional Concrete Layers

A common technique used to increase the flexural capacity of reinforced concrete beams is the addition of concrete layers in the compressive or in the tensile side. Until now, there are limited studies for the effect of the concrete shrinkage on the performance of the strengthened beams. In most of the published studies, concrete shrinkage is ignored and perfect connection is assumed between the old and the new concrete which is not conservative. In this study full scale beams strengthened with additional concrete layers in the tensile side have been investigated. The results of an experimental investigation together with numerical and analytical results are presented. The crucial effect of the concrete shrinkage on the slip of the interface is highlighted and the interaction between the slip induced by concrete shrinkage and the slip due to bending loading is presented.