Tyrolit Wire Sawing Technology Chosen For New Street Station Redevelopment

On-time completion of the work, which entailed demolishing the station's old NCP car park, finished the first of three phases in the so-called Birmingham Gateway redevelopment project. Concrete cutting specialist, East Midlands Diamond Drilling (EMDD), was subcontracted to carry out the project by demolition contractor, Coleman &Company.

It was not possible to bring in crushers and breakers, as the concrete main beams and slabs in the car park had to be removed safely from above platforms while the station continued to operate normally.

One of the problems of working over live railway lines was a restriction in the amount of water that could be used to cool the diamond wire during sawing. A flow rate of 25 litres/min per minute is normal, yet EMDD had to reduce this to five litres/min to keep within safe limits.

David Swanwick, managing director of EMDD, commented, The combination of tough concrete and restricted water usage imposed a heavy load on the wire saws.

During trials with different equipment, Tyrolit engineers used their on-site applications expertise to demonstrate that their hydraulic machines and diamond wire could achieve a cutting rate of well over one square metre per hour.

Moreover, the wire itself lasts considerably longer than others we tested. An area of one square metre can be cut with one linear metre of Tyrolit DWM-C three-star, electroplated diamond wire, while some other consumables achieved less than one-fifth of that performance.

Primary cuts were made using two of Tyrolit's large SB wire saws, with two smaller, portable SK-B saws completing the secondary cuts. To keep within the capacity of the lifting equipment, maximum weight of each cut concrete section was 10 tonnes. Size had to be within 6m x 3m so the blocks could be transported away by road.

When phases two and three of the Gateway Project are complete, 12,000 tons of concrete will have been removed to create a station concourse and atrium three-and-a-half times larger than at present. Work will restart in January 2011 and be completed by 2015.