The project included the repair of seven unsupported reinforced concrete crossbeam, panel walls and columns, known as ‘bents’, which form part of the substructure supporting the longitudinal steel beams and deck slab of the viaduct. The repairs involved the employment of hydro demolition techniques to remove deteriorated concrete and reinstatement to their original profile using flowable repair concrete. Works also included the strengthening of one bent and, once the repairs were complete, the installation of a Cathodic Protection (CP) System.

Being unsupported, the designers were concerned that no over break would occur, since this would reduce the capacity of the structure and lead to possible collapse. The restoration of each bent was therefore carried out in a strict sequence of small repairs. On traditional contracts the repairs would be considerably larger with the temporary supports protecting the structure.

Because the M5 slip road passes diagonally underneath the M6 bents, all work was completed in phases in order to keep the M5 open. This created difficulties with the installation of the CP system, which had to be carried out in sections with the field cabling requiring protection from each repair section. In addition, because keeping disruption to a minimum was of the utmost importance to the Highways Agency, some parameters changed during the renovation and CRL had to increase resources, as well as work 24/7 to achieve an imposed traffic management off date of early August.

The Ray Hall Viaduct project was a Construction Management Framework (CMF) contract that has benefited from a culture of partnering, which was shared with and bought into by the workforce, without whom the contract would not have been a success.