Cowi has signed a contract with Japan-based IHI to design the $1.1bn Izmit Bay Bridge in Turkey, which will become the fourth longest suspension bridge in the world.

The bridge is part of a new, extended highway system that links the two Turkish cities of Izmir and Istanbul.

The bridge will be built over Izmit Bay with a free span of 1550m between its pylons, totalling about 3km in length.

The Danish firm Dissing+Weitling is the architect of the bridge.

Construction on the project is expected to start in the beginning of 2012 and will be completed in 2015.