In the US and UK the existing infrastructure is aging and the safety is sometimes questioned. Of all bridges in the US, constructed with reinforced concrete (RC), around 10% are classified as structurally deficient or functionally obsolete. After the collapse of the de la Concorde Overpass (Quebec, Canada), the shear resistance of half-joints has come under intense scrutiny. A half-joint is a particular type of RC structure. The advantages include a level running surface along the bridge deck and support spans, and precast beams that can be easily lifted into place during construction. However, a major disadvantage are the problems associated with leakage through the joint. When assessing the remaining bearing capacity of half-joint structures, the deterioration is often disregarded as current code provisions do not provide guidance to take strength loss into consideration. Above that, available design rules and guidelines differ significantly. In cases where assessors do consider the deterioration, it is unclear to which extent. This paper aims to provide guidance on how deterioration processes can influence the mechanical and structural behaviour thereby facilitating a more accurate assessment of half-joint structures.