Alternative use of an RC portal frame bridge built in 1941

The Verlorenkost Bridge across river Leie in Ghent has a long history, from a wooden bridge in the Middle Ages to an imposing stone arch bridge, decorated with 19th century artistic sculptures. The current bridge was built during the occupation of WW2 as a RC portal frame, to ensure maximum vertical clearance of the river. Design reports from 1941 show that even the military load imposed by the occupying forces was considerably lower than the current design load. A solid FE element simulation was used to verify whether this bridge is suitable for normal road traffic of LM1 or other types of loads. Based on various tests on concrete samples, a class of at least 35/45 has been assumed. The weak point is the quality of the steel reinforcement of smooth rebars, which have a low yield point. The bridge deck of variable depth does not resist the effect of LM 1. Therefore, a LM 5 was considered, which is allowed by the NAD. This corresponds to a realistic frequent traffic load. With the exception of a few areas, the bridge satisfies the requirements. The new traffic plan of the City of Ghent requires the bridge will be used occasionally by road traffic. The road surface itself is supplemented with a 0.15 m thick slab of washed concrete. This increases the fixed load, while the traffic load remains identical. Strenghtening measures are proposed.