Dan-Y-Graig Underbridge Refurbisments

Tender description

The work will involve replacing 2No asphaltic plug joints – 2No hinged joints and a centre joint under the central reservation running for 60 metres. Because of the process required to renew the asphaltic plug joints it is thought that the old sheet waterproofing system will be irreparably damaged during the works and so it is deemed necessary to replace the old waterproofing with an up to date polyurethane elastomer spray applied system which has a far longer life expectancy than the existing system. A red asphaltic sand carpet will be laid over the waterproofing to further protect it during any future maintenance at the bridge. In order to comply with regulation the waterproofing and new bridge joints must be fitted from parapet to parapet. This will require that the asphaltic surfacing is removed and the concrete verges and central reservation on the bridge deck are excavated so that waterproofing can be applied directly to the bridge deck. The existing safety fence between carriageways will need to be taken down, set aside. The verges and central reserve will be reinstated with concrete and the safety fence re-fitted. The Western verge has 4 steel ducts set into the concrete that is being removed. They will be checked and if empty can be removed. They will not be replaced at this time. The East verge contains a drain fitted beneath it this will be removed during excavation and not replaced. Kerb drainage will be installed with rodding access points. As the joints and waterproofing replaced each carriageway will be resurfaced with Hot rolled asphalt. Road markings and reflective studs renewed. In order to carry out the work safely it is anticipated that it will be necessary to install a contraflow system so that an entire carriageway width of the bridge deck can be treated in one hit. The contraflow shall then be alternated so that the opposite carriageway can then be treated. The contraflow system will require enabling works involving the installation of 2 new crossover points which are expected to be installed in the same place as the original crossover points that are now below standard. Removal of 120metres of safety fence will be required at each crossover point, set aside then refitted once the bridge work is complete. The contract is NEC3 Contract.