Additional stability for the entire structure is guaranteed by nine cable “spoke” arrangements plus diagonal spiral ropes with a total length of about 2km. Numerous test series were required before the supreme building authority was prepared to grant an individual approval for this new type of all-glass barrel vault.
Centring had to be erected for assembling the glass roof, which had to be temporarily pre-stressed during construction. Upon completion, the centring was lowered and the pre-stress adjusted in defined stages. Special care was needed to ensure precise positioning of the individual panes, which, in the end, guarantee the accuracy of the form of the whole roof.