A9000 9 Forth Road Bridge - Truss Chord Strengthening

Description

The Forth Road Bridge (FRB) is a long span suspension bridge which carries the A9000 over the Firth of Forth. It was opened in 1964 and is a Category A listed structure. The FRB’s deck is currently supported by a stiffening truss which is present at both the main and side spans. This truss transfers all applied loads to the suspension system of the structure. The top and bottom chords of this truss system are constructed from welded box sections, which primarily carry high tensile and compressive axial forces. Historic and recent assessments have found the top chords of the FRB Stiffening Truss to fail and therefore require strengthening works at the splice connections. The scheme requires a contractor to conduct steelwork strengthening of the box chord splice plates across the structure. The contractor will be required to work within short weather windows to remove and install new splice plates at the chord connections. The contractor will need to install pre-designed temporary props to allow the existing splice plates to be removed in a sequence. Alongside this, the contractor is required to blast clean the existing internals and externals of the box girders and apply a new corrosion protection system. Existing paint system is lead based. The contractor is required to provide access to all locations but may utilise existing FRB staging board systems as required. However, roped access will be necessary to install an additional strengthening detail if staging boards are used. The Contractor must have demonstrable experience of similar works. The Contractor must also be approved to the applicable sector schemes for these kinds of works. Estimated value of the works is 2,500,000 GBP.