Construction of the Orwell Bridge commenced in October 1979 and was completed in December 1982. The main span was constructed by Stevin Construction B.V using a balanced cantilever technique, casting sections on alternating sides of the pier in a weekly cycle.
The bridge is constructed of a pair of continuous concrete box girders with expansion joints that allow for expansion and contraction. The girders are hollow, allowing for easier inspection, as well as providing access for services, including telecom, power and a 711mm water main from the nearby Alton Water reservoir.
The Orwell Bridge was opened to road traffic in 1982 to allow the A45 (now A14) over the River Orwell.