Modelling of Mechanical-Corrosion Interaction in Dapped-End Connections

Abstract

The aim of this master thesis is to model the behavior of reinforced concrete dapped-end beams subjected to the effects of corrosion. This type of connection is encountered in many reinforced concrete bridges and presents a concentration of stresses due to the abrupt reduction in cross-section. In addition, the infiltration of water and salts into the cracks can severely damage the structure and reduce the resistance of these elements.

The model used in this work is a kinematic-based model adapted to take account of the effects of corrosion. The model predicts the ultimate strength of connections as well as their crack width. The effects of corrosion modelled in this work are the degradation of steel's mechanical properties and the reduction of bond strength between the concrete and reinforcement due to corrosion.

Several models are proposed to take into account these two effects, and then compared in order to retain only one for each. The complete behavior of corroded reinforced concrete dapped-end beams is then studied, and the theoretical results are compared with experimental data gathered from scientific literature. Finally, the parameters that can influence the behavior of corroded half-joints are investigated.

The model predictions follow the expected reduction in strength due to the effects of corrosion, and a reduction in strength similar to that observed for less reinforced uncorroded specimens. However, more tests should be conducted on corroded dapped-end beams in order to conclude on the validity of the model.

The model presented in this work can be used as a basis for future studies, for example to model pitting corrosion more locally in the nib of the dapped-end.