Steel portal frames are commonly used for single-storey construction, particularly for factory and warehouse buildings. These frames provide support to a steel roof and a variety of forms of external wall construction including: steel sheeting supported by girts, masonry, dado walls, precast concrete panels and tilt-up concrete panels. In the event of a major fire within such a building, it is possible that the external wall, or part of it, may collapse outwards, a situation the BCA stipulates is to be avoided. There are two possible approaches to designing external wall panels against outwards collapse. The first approach is to ignore the presence of the steel frame and design the wall panels to resist fire exposure—assuming them to act independently of the frame. In this case the connections between the frame and the wall panels do not matter but the wall panels must be able to resist a worstcase fire with no support being provided at the top of the panels. The second approach, which is the focus of this publication, is to design the connections between the panels and the frames such that they will not fail during the fire. This does not mean that all connections must be designed in this way but only those which offer necessary support.
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