Shear strength of slab
The 115-YEAR old Jamestown Viaduct in Scotland has been strengthened by the installation of a reinforced concrete slab, which forms a composite structure with the existing trusses and cross girders.
Principal contractor Mowlem installed steel diaphragm panels in the apertures between the cross girders, transferring shear forces between the slab and the tops of the trusses.
The design was developed by Corus, and trials had shown it was possible to weld to the 19th century deck plates to provide permanent formwork for the slab, which is linked to the viaduct structure through 8600 stud connectors.
Network Rail required the external appearance of the viaduct to remain largely unaltered by the strengthening work, which will enable the structure to handle 27million tonnes of traffic per year.