Spencer Bridge Engineering were commissioned to undertake these works due to the success at Forth Road Bridge, Humber Bridge and M48 Severn River Crossing in the UK. Using their bespoke ‘cable crawler’ access gantry, the project team installed a dehumidification system to the main cables to inject dry air into the cable at a number of locations. This reduces the speed of corrosion and extends the life of the cables.
Spencer Bridge Engineering’s approach to works of this type requires only a single carriageway possession for installation of our bespoke ‘cable crawler’ gantry. Once the gantry has been manoeuvred from the delivery vehicle to the landing trestles, the carriageway can be re-opened with only a one lane closure.
The company’s in-house development of the ‘cable crawler’ gantry for suspension bridge main cables has not only had significant positive contributions to project programme, quality and methodology, it also created opportunities to carry out other essential works without the requirement for carriageway possessions on heavily used and critical transport routes.
The gantry design also allows a very high level of containment and protection, ensuring any risks to bridge users are removed, as well as providing an ideal working environment within the platform.
The containment around the platforms is designed to be opened in high wind conditions so no excess loading is applied to the bridge structure.
The platform design and the access provision to the platform has the added benefit of allowing project staff, client representatives and consulting engineers to access the inspection area without the need for rope access qualifications, even at the highest level of the suspension bridge cable.
