English4
RMD Kwikform’s new Alshor Plus shoring system is being used on the new £445 million Wembley National Stadium in London. Specialist concrete contractor, P C Harrington, is using the new lightweight aluminium system to support the in-situ concrete floors of the contract. Here Howard Matcham, RMD Kwikform’s Business Development Manager, describes how the combination of an innovative new system and some inventive thinking is helping to complete the work ahead of schedule.
Constructing the 275mm to 2400mm thick reinforced concrete cast in-situ slabs for the new Wembley Stadium was, from the outset, going to call for meticulous planning, attention to detail, and the use of a versatile, high-load-capacity shoring system designed to maximise the speed of construction. The concrete slabs would ultimately require around 40,000 square metres of support and back propping, and the work had to be completed within a tight timescale. A close working relationship between the shoring provider and the substructure and superstructure contractor was, therefore, going to be a vital ingredient in the project’s success.
The scale and complexity of the geometry of the floors, which take up approximately one third of the Stadium’s one kilometre circumference, presented no irresolvable challenges for Alshor Plus, which was designed to provide soffit support for such static concrete frame structures. However, to achieve the maximum site efficiency, Site Project Director, P J Harrington, was convinced that using the system to produce a series of mobile tables would – despite the shape of the building - dramatically increase productivity, reduce site labour costs and minimise the amount of equipment required.
The plan, which was then developed jointly by P C Harrington and RMD Kwikform, ultimately resulted in the shoring being undertaken using around 30 different sizes and configurations of Alshor Plus mobile tables. The sizes of these tables were determined with two aims in mind; to achieve the maximum use of tables on the project, and to achieve the maximum reuse of each table on successive pours. Infill areas between the tables and adjoining stairwells, columns and beams are being completed using site-assembled “static” sections of the shoring system.
Phase One of this element of the project started in November 2002, and Phase Two commenced in February 2003 and is due for completion in September 2003. Currently the work is two months ahead of schedule. The 45-week programme has so far involved the pouring of some 90,000 cubic metres of concrete and the use of 15,500 tonnes of steel reinforcement.
Each floor is being completed in 13 pours – the largest of which is approximately 1,200 square metres - with three areas being temporarily omitted to accommodate the erection cables for the Stadium’s huge lattice steel arch. Back propping is achieved using a combination of Alshor Plus and P C Harrington’s existing stock of aluminium shoring.
THE SHORING SYSTEM.
