Recent article for The Water Jetting Association by Mr David Kennedy
Water Jetting Association member Aquaforce Concrete Services has completed an 18-month project to assist in the removal of structural bearings on the Ouse Bridge that takes the M62 over the River Ouse in East Yorkshire. The successful programme of works, completed for the Highways Agency, demonstrates both the benefits of water jetting and of the standards set by the WJA’s codes of practice and water jetting training, says Aquaforce Concrete Services General Manager Gavin Thomas…
Aquaforce Concrete Services has carried out floor cutting and hydro demolition works on the Thames Bray Bridge Widening Project for the M4 Smart Motorway development, on behalf of the Balfour Beatty Vinci JV for Highways England.
The Smart Motorway project will see 11 bridges over the M4 between junctions 3 and 12 replaced or upgraded to ensure they have capacity to accept the new four lane carriageways.
The complex Thames Bray bridge widening works require the ‘stitching’ of three additional longitudinal deck beams to the existing deck. The new bridge beams, each weighing nearly 400 tonnes were installed on the North side of the existing bridge and tied to the existing sub-structure by structural bracing, extending the width of the bridge deck by eight metres and enabling the addition of four traffic lanes.
To facilitate the works, Aquaforce Concrete Services was engaged to carry out the removal of 1900mm of the existing northern cantilever concrete deck slab.
To ensure maximum efficiency within the already tight programme, Aquaforce removed the outer 1300mm of the slab using floor sawing techniques, cutting the slab into 2000kg, 2000mm x 1300mm sections, lifting them out a section at a time. Fifty one sections were removed in total.
The remaining 600mm of the concrete slab was then removed using high pressure water jetting (hydrodemolition) to ensure the final 600mm of existing rebar was left in place, undamaged and ready for connection to the reinforcement in the new deck.
As the Thames Bray Bridge carries the M4 Motorway over the River Thames at Bray, it was critical that no waste water from the process entered the water course below. A bespoke encapsulation system was developed by BBVJV and Aquaforce and installed by BBVJV to ensure protection of the water course.
The concrete removal works were carried out, on budget, on programme and to the satisfaction of the Client and the Environment Agency.
The upgraded M4 smart motorway is expected to be open to traffic by spring 2022.
BBV JV has released the follow video of the works so far.
Aquaforce Concrete Services has been awarded the contract to provide hydro-demolition works on the Kariba Dam Rehabilitation Project starting Q3 2020 supporting Freyssinet International who will be undertaking the main contract works.
The Kariba Dam is a double curvature concrete arch dam in the Kariba gorge of the Zambezi river basin between Zambia and Zimbabwe. Measuring 128m tall and 579m long, the structure forms Lake Kariba and holds 185km³ of water. Constructed in 1955, the dam is essential for the energy security and economic development of the region.
Routine monitoring of the dam identified the need for rehabilitation works to ensure its long term efficient operation. The Kariba Dam Rehabilitation Project (KDRP), financed by the World Bank started in 2017 and will involve the reshaping of the plunge pool and refurbishment of the spillway gates. The project is due for completion in 2025.
As part of the project, Aquaforce Concrete Services will remove approx. 1000m3 of concrete from the six dam sluices to facilitate the required rehabilitation works. To undertake the works, Aquaforce will use a combination of robotic and hand lance water jetting techniques. Investment exceeding £1,000,000.00 is planned in state of the art hydro-demolition equipment and water treatment plant from UK based Calder Ltd which will be required to carry out the works in accordance with the engineer’s exacting standards.