Elastic behaviour of the steel part of a shear connection with MCL composite dowels - Design basis for serviceability and fatigue limit states

In this paper the authors present numerical and analytical approaches for establishing rules for dimensioning MCL steel connectors for serviceability and fatigue limit states. Two unit models were adopted for the stress calculations by means of FEM: the first one for taking into account the notch effect of the longitudinal cutting line on the stress pattern in a uniformly tensioned steel plate, the second one for determining the stress pattern in a steel connector due to longitudinal shearing between the steel and concrete parts of the beam. A mathematical approach for establishing an envelope of the connector's resistance is presented. A detailed study of the fatigue behaviour of steel connectors is presented in the second part of the paper. Possible crack patterns and their development mechanisms are described, justified by appropriate FEA and test results.