Working with Highways England, Connect Plus and Osborne, BS Steels has been strengthening the welds on the underside of the viaduct spans on the M25 Gade Valley Viaduct.
The Gade Valley Viaduct, by Junction 20 of the M25, is a composite structure, comprising 11 spans of 8 steel box girders, and carrying the motorway over the Grand Union Canal, the River Gade, a major road and the main London-Birmingham Railway. By any standards, therefore, it represents infrastructure critical to the UK’s economy.
Though completed only in 1987, a shortfall in fatigue life had been identified, requiring structural strengthening to increase its life.
This is probably BS Steels’s most challenging project to date! It will also be our longest continuous project, with a dedicated team likely to be on site for several years, and the need to phase work according to traffic needs.
By clicking on the images below, you can inspect a set of strengthening plates, fitted over existing butt welds, under one span of the viaduct. Under this one span alone, there is a total of 43 stiffener locations, with some 300 plates and 9000 TCB bolts.