Bolt fixed glazing: large scale rooflights

Abstract

The generic support structures described in the previous section suit a range of roofs in a single plane, whether pitched or (nominally) flat. Supporting structures which are facetted or curved to form complex geometries require a slightly different approach. These supporting structures are dictated more by the demands of the form that is being created rather than by optimising the position of supporting members to maximise visual transparency through the structure. Structures for arches or curved surfaces are usually made with as little structural depth as possible, with the visually successful types using a single ‘plane‘ of structure formed in ‘ladder’ forms. Circular hollow sections and box sections are preferred for their visual consistency regardless of where the glazed roof is viewed below the roof. The ladder principle is actually two vierendeel trusses linked together, with the short cross members welded to the long members.