I stand corrected. "The arch will stand 133 metres above the pitch and will support all the weight of the north roof" bbc website. 1 - 0 to you amy and eaststander
As always it isn't that simple. It is a design feature that need not be there (how many other stadiums have one?) but it does do the job that a much cheaper alternative could have done. So really it is only there for fancy even though it has a structural function (a bit like Jordan's boobs?)