Crack Assessment of a Very Thick and Bloc-Like Concrete Member

This paper presents the results of recent research activities on the hardening-induced stresses and the risk of cracking in very thick concrete members. These activities focus on a very large member with bloc-like dimensions. In contrast to typical member types such as ground slabs or foundation walls, bloc-like members are dominated by temperature gradients in all three dimensions (height, width and length) at the same time. Besides, the comparably high stiffness of these members leads to very low external restraints in cases of common applications. In these cases the members considered show distinct eigenstresses (residual stresses or self-balanced stresses) but only low restraint forces and moments. The assessment of the hardening-induced cracking of such members therefore requires a detailed analysis of the temperature and stress fields.
This contribution presents comprehensive investigations on the hardening-induced risk of cracking of a typical bloc-like concrete member in the form of an underwater foundation. The results of the simulation were compared with selected practical observations during the construction of the underwater foundation of a recently built bridge.