Shepherd Construction is installing Corus Bi-Steel’s Corefast system at its St Paul’s Square scheme in Liverpool making a 21-week time saving on a construction programme originally estimated at 105 weeks using a traditional technique.
Corus’ rapid erect modular Bi-Steel building core system was specified for the lift/stair cores in the striking 17,000m², eight-storey office building which is part of phase two in the City centre mixed development scheme. The office block will include a striking glass elevation that will externally feature the projection of a rock crystal whilst providing privacy and security for occupants in the building.
Early designs for the building specified a steel frame with in situ concrete walls to three stair cores, plus two pairs of lift cores with no cross bracing so all the elevations could be fully glazed. However, working to this design would have brought the initial construction programme in later than the client required, and over budget due to the cost of preliminaries.
Utilising Corefast provided the Shepherd Construction team with unprecedented flexibility, shaving weeks off the original construction programme, bringing major cost savings on the build programme, and reducing the amount of craneage. By re-submitting their tender specifying Corefast, the construction programme was reduced from 105 to 84 weeks and would only require one tower crane – instead of the two specified in the original design – bringing the costs back within the client’s budget and meeting the required completion date.
Tim Waters, Shepherd’s Project Manager comments: “Shepherd is extremely keen to embrace innovative modular construction technologies, our team was impressed by Corefast’s benefits - especially its speed of construction. This is tight city centre scheme – so speed of installation was essential. Corefast can be erected up to six times faster than an equivalent concrete core – and this proved a key factor in our decision to use the product.”
Waters continues: “Not only has Corefast helped to reduce the construction programme, it has also served to minimise the safety risks of working at height. The stiffness and rigidity of Corefast meant we could reduce the number of structural cores required from five to three providing us with significant cost benefits.”
Billington Structures, the steelwork contractor for the project, detailed and fabricated the Corefast modules at its Bristol facility and is now carrying out the erection of the three cores. Mike Fewster, Billington’s Operations Director comments: “The core erection has gone more smoothly that we’d dared to imagine - in many ways we’re just treating them like large plate girder columns. The real benefits for us are that we can easily achieve very tight tolerances on building plumb and all the connections for the rest of the frame are already in place. An added plus has been the way we have been able to incorporate all the builder’s work attachments for the lifts and façades back in our factory.”
Installation of the cores commenced at the beginning of December 2006. Each core is being erected in two storey sections with each stair or lift core taking four days to erect, grout and concrete. Upper levels will take only three days per two-storey height, as grouting is not required. The scheme is due to be completed in April 2008.