Hydrodemolition used to remove damaged ski lift concretePublished 23/12, 2015 at 14:14
An Aquajet remotely controlled Aqua Cutter 410A hydrodemolition robot has been used by specialist contractor Corvara Industri & Skadeservice to remove decayed concrete on pylon foundation bases in the Swedish ski resort of Åre prior to replacing with fresh concrete.
Åre’s ski lift system, which takes skiers and holidaymakers up the side of the 1420m high Åreskutan mountain, was built in phases starting from the late 1970s and has helped turn the previously small village into one of Sweden’s leading winter sports resorts. The foundation blocks had aged to the point where Corvara had to use the hydrodemolition robot to remove 200mm of decayed concrete, estimated to have a compressive strength of about 44Mpa, so that new concrete could be applied.
“The robot is so light and compact that we are able to lift it up the side of the mountain on the cableway and then lower it onto the blocks,” said Corvara project supervisor Mattias Carlsson. “Each block is between 3m and 4m high and there is a ledge of around 750mm in width, that the robot can stand on. The machine is so compact and manoeuvrable that it can be driven along the ledge and even around the corners, so that it can reach all surfaces on the foundation without the need for any lifting devices.
“Jack hammers could of course have been used for this job, but they cause noise and dust, which in this pristine environment is not desirable,” said Carlsson. “It would also have caused critical vibration damage to the foundations and the pylons. With the hydrodemolition technique it was possible to keep the cableway open during the complete restoration. Using the hydrodemolition robot is faster, the reinforcement of the blocks remains intact, and the casting surface has far better adhesion properties than that produced by mechanical chiselling.”
Use of hydrodemolition was specified in Corvara’s contract, which covers 12 foundation blocks and runs from 2015 until the end of 2016.
Corvara, which has service centres at 35 locations in Sweden and employs a workforce of around 600, specialises in repairing damage to industrial installations and is a supplier of high-pressure, suction, hydrodemolition and blasting services throughout the Nordic region.