The EJ Whitten Bridge opened in 1995, and forms part of the M80 Orbital Freeway around Melbourne, Australia. But since opening, congestion, bottlenecks and accidents regularly caused delays for the 165,000 motorists and 22,000 trucks that use the route every day.
As part of the M80 Ring Road Upgrade to increase capacity and improve safety on the freeway to create more reliable travel times, widening of EJ Whitten Bridge commenced in 2017. The twin three lane carriageways of the bridge were joined together to create a single structure with five lanes in both directions.
Unusually for a bridge, provision for widening had been made in the original foundation and pier design, through infilling the central reserve gap between the two viaduct structures with a third concrete box girder. However, COWI produced a more innovative design, incorporating twin composite steel boxes with an in-situ concrete deck placed on precast concrete slabs. The lighter weight of the superstructure elements resulted in the elimination of any strengthening requirements for the existing substructure.
High anti-climb public safety barriers were included in the project scope, as was an upgrade of the vehicle barriers to high containment level. Future maintenance access and durability were also important considerations in the design of the new structure and upgrades.
The project, which was subject to a compressed (5 month) design programme and 12-month construction programme, was completed ahead of schedule in October 2018.