Half-joints degradation: analysis of some case studies

Existing Reinforced Concrete (RC) bridges, due to their age, are very often affected by significant deterioration phenomena, also intensified by lack of maintenance, which strongly reduces their strength with respect to the design load combinations. In particular, half-joints were widely used in the RC bridge typology until the end of the 20th century. As well known, due to the static scheme adopted, and recurrent failure due to fragile mechanisms, to date these elements are recognized as critical, since their strength is particularly affected by degradation frequently provoked by erosion caused by rainwater infiltration from the roadway. This phenomenon, definitively, leads to a marked concrete cover reduction and corrosion of the reinforcing bars. This paper deals with the analysis of certain types of half-joints employed in existing reinforced concrete bridges. To this scope, some case studies are illustrated and discussed to highlight weakness points of the typologies analyzed and causes of defects observed.