This is a type of slabs which is generally adopted in construction of bridges. Bridges are subjected to  two loads moving load from the vehicles and Wind load. These slabs are adopted at a place where there is a need of redirecting wind load and if there is a long curve in direction of slab these slabs are adopted.  It resists the fall of bridge due to heavy wind load.

They were originally built of stone or brick but these days are built of reinforced concrete or steel. The introduction of these new materials allow arch bridges to be longer with lower spans. This is a one of the types of concrete slabs.