The Government has agreed to fund the £93m strengthening and repair programme to a key viaduct on northern section of the Aston Expressway between the city centre and the M6 motorway.
The Tame Valley Viaduct, which carried about 80,000 vehicles a day, was starting to show signs of deterioration.
Without government funding, the viaduct would need weight and width restrictions within a few years and, over time, the link could potentially face full closure.
The Government is putting £72m into the project which is expected to cost £93.5m with the remaining funding coming from Birmingham City Council and the Local Growth Fund.
Work is due to start on an extensive strengthening programme next year with structure remaining open to traffic throughout. The vast project is expected to take nearly five years to complete.
Proposals involve major strengthening and refurbishment works on the viaduct, ensuring it can continue to carry heavy vehicles. It will remain open to traffic throughout the duration of works.
There are also plans to apply a protective anti-corrosion paint system to the structure alongside other general refurbishments, preserving the longevity of the viaduct and minimising the need for future work.