Some of our Drilling and Sawing projects
The Coronation Parade promenade and breakwater in Folkestone, Kent was built in the late 1930s. It consists of 91 reinforced concrete arches and promenade with a retaining wall to the rear. After many years exposed in the harsh sea environment the structure had begun to fail, sections of the concrete had started spalling and corrosion was eating away at the steel reinforcement contained within the concrete. The local council contracted a specialist company to carry out comprehensive concrete repairs and at the same time install into the entire structure an Impressed Current Cathodic Protection System. This system will prevent further corrosion of the steel reinforcement. Diamond Edge Drilling Ltd were called in by Concrete Repairs Ltd to carry out all the drilling and chasing required for the installation of the system anodes and cabling.
The main elements of our work included but were not limited to:
- 1360 41mm diameter holes drilled 2.4 to 3 metres deep, down into the arch walls
- 700 41mm diameter holes drilled 2.4 to 3.2 metres deep, down into the rear retaining wall
- 2720 41mm diameter holes drilled into the promenade deck
- 6000 linear metres of channeling chased into the promenade deck
Due to the need to preserve the steel reinforcement within the structure Rock Drilling was selected as the most suitable drilling method (rather than Diamond Drilling). This was due to the fact that the rotary percussion action of the tungsten rock drill head would not cut through the steel reinforcement if encountered whilst drilling. This proved to be quite challenging in some of the heavily reinforced areas! The rock drilling was carried out using a self-contained automated rig fitted with a specially adapted 3-metre long drill mast. Impressive production rates of up to 120 linear metres of drilling per shift were achieved using this method.
We cut the chases in the promenade deck to the specific widths and depths using an 84 horsepower floor saw. Cutting the chases with such a large saw required a lot of skill from the operators, but resulted in massive productivity gains when compared to using smaller saws and handheld methods. The channels were broken out using low vibration handheld breakers by a team of operatives working in rotation to avoid HAVS issues. Up to 400 linear metres of chase was completed per day with just one floor saw.
During the course of the contract Diamond Edge worked in close co-operation with the Client and the other trades on site to ensure fluent operations where contractor activities inevitably crossed. Our work was completed on program despite being at the mercy of the elements!
As part of the £6bn Thameslink upgrade, Blackfriars Station was completely rebuilt and now extends across the Blackfriars Bridge. Part of the work involved demolition of platforms and roof of the over-ground station and the main contractor had to ensure that trains could continue to run through Blackfriars underground station before the demolition and reconstruction works could proceed. The solution to this was a massive steel cover for the tube lines known as a Track Protection Structure (TPS) – essentially a series of steel arches connected to a steel base which was secured to the underground platform.
Diamond Edge Drilling Ltd, in partnership with JJM Rail Ltd, were contracted to carry out the strengthening and foundation works to the underground platform required to allow construction of the TPS. Twenty-two bases had to be formed in the platform to support the weight of the structure and so that the steel arches could be anchored. The bases would each be formed with reinforced "mini piles" down through the platform and into the foundations below with a reinforced concrete capping beam on top of the piles to act as a pad for the steel arches. Our task was to diamond drill the holes down through the platform and foundations for the mini piles and diamond floor saw cutting to form openings in the concrete platform for installation of the capping beams.
For the mini piles, we diamond drilled two hundred and fifty holes at 107mm diameter up to 3 metres deep into the reinforced concrete and masonry platform and foundations. Holes were spaced at only 20mm apart and could not deviate into each other so drilling levels had to be precise. Six diamond drilling rigs fitted with 2 metre drill columns were used and operated continuously. The capping beam openings were 300mm wide and varied from 1 metre to 3 metres in length. These were cut through the 350mm thick concrete platform using electric diamond floor saws rather than diesel or petrol powered saws due to the fume risk.
As with a lot of work on the Underground strict timescales had to be adhered to. Blackfriars underground station was closed to the public during weekends to facilitate these enabling works. We were given two 48-hour long weekend possessions of the station to complete the drilling and sawing work including set-up time on the platforms, clearing the site and making safe our work ready for the resumption of public services on Monday morning.
Telephone: 01732 832223