Highways England contracted Interserve to project manage the re-lining of Vigo Bridge which carries the A1 over the Sustrans national cycle network at Chester-le-Street.
The object of the project was to ensure the bridge’s safety and prolong the lifespan of the structure. Meldrum Structural & Civil Engineering Ltd, part of the Meldrum Group, was appointed as main contractor.
This was a complex operation.
Before the metal liner could be installed, a material had to be found which could be used to fill the semi-circular jack arches and bearing shelves, eliminate all voids and create a continuous flat surface whilst also providing adequate compressive strength to hold back the Foamcrete which would subsequently be used to create a solid mass between the metal liner and the roof of the bridge.
Meldrum’s called in Foamspray Insulation. It was agreed that the system that would meet all requirements was Duratherm HFO manufactured by Isothane.
Duratherm® HFO Spray Insulation & Stabilisation system is a low global warming potential two component, 1:1 ratio, rigid foam system comprising of the 4th generation hydrofluoroolefin (HFO) blowing agent. When processed through suitable spray machinery the product produces a rigid foam of approximate density 40kg/m³ with exceptionally good compressive strength at 220 kpa.
The jack arches measured 0.8 metres wide, 0.5 metres high and 14 metres long. The bearing shelves measured 0.5 metres deep, 0.5 metres high and 0.8 metres wide.
Foamspray Insulation first applied a bonding coat to ensure the Duratherm HFO adhered to the existing brickwork.
Foamspray Insulation then installed the Duratherm HFO to completely fill the jack arches and bearing shelves, filling all voids to create a completely flat surface throughout the roof of the bridge.
Update – 9th February 2021
Jerry has completed a complex scheme on the Vigo Lane job. This consisted of filling voids under the A1 motorway at Birtley and has achieved this to a high standard. The works were completed within the timeline of the programme.
Foamspray Insulation as a company have been very reliable, flexible and completed all spraying to a high standard with adequate testing requirements met to designated specification and set dates controlled by the programme.
I would recommend Foamspray Insulation to other clients and wish them the very best for the future
Meldrum Construction Services Limited
Building Solutions with Integrity