Ukrainian contractor executes challenging underwater projectPublished 6/3 at 13:17
In a war torn Ukraine, specialist concrete cutting contractor, TEM Diamond, based in Kyiv, performed a unique project involving the wall sawing of underwater concrete structures at the Kyiv reservoir. Andrei Bushmarin reports.
The Kyiv reservoir is a large water body located on the Dnieper River in Ukraine. When one of the piers along the waterfront required renovation, the local authorities contacted TEM Diamond to perform the cutting of its underwater structures. At first, the task seemed insurmountable because it involved demolition of a monolithic slab made from extremely hard reinforced concrete. After some deliberation, TEM Diamond decided that the only viable solution was to use a Hilti DS TS 32 hydraulic wall saw. The thickness of the slab varied from 300mm at the waterline to 580mm below water. The biggest challenge was doing the cutting underwater at a depth of between 0.5m to 3.5m. Visual control of the operation was impossible so the contractor had to rely only on its experience and professionalism.
Before setting up the wall saw, the pier floor was de-sanded using a water pump. Professional divers were contracted to fix the wall sawing system onto the concrete structure. The sawing process was regularly interrupted to check the depth of the cut. The pressure that water put on the diamond blade slowed down the cutting process, particularly when the blade was half above water. Once the underwater structures were cut into 8t to 10t blocks, 200mm holes were drilled in them at a depth of 1.5m. A Ø30mm wire rope was passed through the holes and hooked to a floating crane. The crane tore out the particularly challenging first section with a force of 70t; the remaining slabs were demolished with a force of 20t to 50t.
On this project TEM Diamond used a Hilti DS TS 32 hydraulic wall saw with a power rate of 32kW, 1,200mm and 1,600mm diamond blades featuring ‘Arix’ segments, a 5kW core drilling system and 200mm core drills also equipped with Arix segments. The volume of concrete structures cut totalled 130m, with the equipment working underwater for 53h. The job was completed on schedule to the full satisfaction of the specifier.