Engineers will this week begin work on repairing cracks on Boston Manor Viaduct, a crucial M4 motorway structure that is part of the Olympic Route Network.
The Highways Agency will begin repairs of the 15mm long hairline cracks on the Boston Manor Viaduct just west of junction 2 near Hounslow.
Following the discovery of cracks on the steel bridge last month, the Highways Agency was forced to impose a 7.5t weight restriction on the damaged stretch diverting coaches and lorries onto busy local roads.
Repairs will consist of grinding out the cracks or putting steel compensation plates over them to reduce load on the welds.
The Highways Agency has not given a firm date on when the repairs will be completed but said it is confident it will be before the Olympics.
The affected section is on the Olympic Route Network (ORN) and will be used to carry coaches travelling to and from Heathrow airport and the Olympic Park in East London.