In the first part of the article, published in CPI - Concrete Plant International, Issue 3, 2012, the phenomenon of progressive collapse, as a consequence of an initial damage to one or more load bearing structural components was discussed, and strategies to analyze the problem for precast buildings were explained. According to the size and destination of the building, three design methods could be adopted. The indirect method gives minimum requirements for tie forces. The alternative load path method consists to admit the collapse of a limited local area of the framework, and assures that the adjacent areas of the structure surrounding the damage, provide for an alternative load pad, possibly in a distorted condition but without leading to collapse of the whole structure. The specific load approach method could be applied to structures for which no alternative load path is possible.
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