AMEC has specified a vibration-free pedestrian controlled drill rig for pile-cutting on the £180 million Docklands Light Railway terminus at Woolwich Arsenal, London.
The E-Z Drill 210B rigs, hired from distributor Castellan, have been used to drill horizontal holes into the top of concrete piles from 700 mm to 1,050 mm in diameter to expose the reinforcing. This will be tied into the cast in-situ slab of the station roof, enabling excavat ion to take place beneath it.
Amec operatives use the drills to bore a single 45 mm diameter hole at depths up to 750 mm into the side of the piles.
A hydraulic burster is inserted into the hole to break the concrete away from the reinforcement rods and the plug of concrete is then lifted away by excavator.
Castellan director Colin Jailler said: 'Operatives are not directly attached to the rig so there is no transfer of vibration unlike hand-held drills.
To my knowledge it is the only drill that can be used all day without requiring a break for the operator.'
The rigs use a compressed Chicago Pneumatic CP32 rock drill mounted in a frame with two wheels at the front and legs at the rear, enabling the operative to reposition and align where necessary.