Multiplex is currently working out how to execute one of the most critical operations on the Wembley national stadium project, to be carried out in May
The crucial job will be swapping temporary cables supporting the 133 m high, 1600-tonne arch that holds up the stadium roof for permanent cables. Multiplex said it was evaluating two options for this work.
Another difficult operation is taking away temporary supports holding up the north and south roof sections, transferring the loads to the permanent structure. Ashley Muldoon, Multiplex’s project director, said: “The most important part is in September when we start to de-prop the roof, which means all the loads go through the permanent design. It’s not something that happens overnight; it’s a progressive thing that happens over a number of weeks.” Muldoon added that this operation was not as difficult as raising the arch last year.
Multiplex said the innovative approach of steelwork contractor Hollandia had enabled it to claw back two months and get the project back on track after previous delays.
The Dutch company, which replaced Cleveland Bridge in July last year, is responsible for finishing the stadium’s structurally challenging roof. “Hollandia has come up with some real innovations with this project and we are now ahead of schedule with some areas of the roof,” says Noel Henderson, Multiplex’s global head of construction.
Muldoon said prefabrication was the key to getting the roof finished on time. “Cleveland Bridge used to bring lots of small components in and assemble them on site. Hollandia bring in larger sections on barges from Holland. All we are doing here is some basic assembly.” Muldoon added that the use of off-site fabrication protected the job against the risk of prolonged bad weather. He said Hollandia had also devised an on-site production line to make it easier to assemble some repetitive roof elements.
Night working has helped speed up construction and has freed up crane time during the day. The precast concrete seating bowl sections are being craned into position during the night, as it is a relatively quiet operation.
Work started on constructing the main roof over the stadium bowl earlier this week. A section of the truss at the leading edge of the north roof was placed on temporary supports then connected to the oval truss that runs around the outer perimeter of the stadium with a steel beam.
Multiplex says the roof will be “substantially complete” in September and that the retractable roof section fitted to the south roof will be finished by December, when the turf on the pitch will be laid.
Work is progressing on other parts of the stadium: Multiplex says several plant rooms are fully fitted out and are being commissioned, some escalators are finished and the cladding
is being installed both north and south stands. The grass for the pitch has been planted and is “growing well”, according to Henderson. This will be laid on to the pitch in December ready for matches in May next year.