DWM Plant Limited have recently completed a Labour, Plant & Material Groundwork Package on the prestigious 268,000 sq ft Elisabeth House project in St Peters Square Manchester for London based AJ Morrisroe. With space at a premium, basement construction forms an integral part of city centre developments and as part of the OSPS scheme a 6.5m deep basement was constructed, using a contiguous piled wall.
The DWM package was completed over a 20 week period, involving many obstacles and logistical problems, which were overcome by effective planning and management. Obstacles included heavily reinforced concrete base slabs, which were broken out and removed from site. Temporary works were critical in the sequencing and programming of the works, which involved the propping to the contiguous piles and the interface with existing walls in specific locations.
Excavation works for pile caps and capping beams, generated significant amounts of spoil, which resulted in the disposal of 15,000m3 of excavated material from a very restricted city centre location. The works included the breaking down and removal of 600mm diameter CFA piles, which introduced the use of the latest excavator mounted pile croppers. Localised sheet piling was also required, during the capping beam construction, for the protection of exiting services, which ran around the perimeter of the site. Drainage was installed below the slab, which included the installation of a Tubosider attenuation system, accumulating in the final connection to an outfall, which required the construction of a timber heading.