Since the 1980’s, several buildings throughout the world have been subject to gas explosions, impact by trucks or airplanes, or car bomb attacks. In many cases the effect of the impact or explosion has been the failure of one or more critical structural members at the perimeter of the building. After the failure, the load supported by that member could not be redistributed and part or all of the structure has collapsed in a progressive manner. The phenomenon that occurs when local failure is not confined to the area of initial distress, and spreads horizontally and/or vertically through the structure, is termed progressive collapse. The phenomenon of progressive collapse has been extensively studied for cast in-situ buildings, and literature is available. However, for precast concrete structures, much less design information exists, and addresses mainly bearing wall structures. For precast structures in general and skeletal structures in particular, nearly no practical design guidelines exist. The fib commission on Prefabrication has recently published in Bulletin 63 a Guide to Good Practice on “Structural Integrity of Precast Concrete Structures under Accidental Actions”. The present knowledge on the subject and guidelines for the design of precast structures against progressive collapse are dealt with in this article that represents part 1 of two articles about this topic. An extensive overview about the treatment of progressive collaps in The US will follow in CPI 04-2014, presenting US Codes and Standards as well as their consequences for the design of precast concrete structures. Together, both parts of this article are written by authors from fib and PCI, following a series of joint articles presenting different views of both assiciations on certain topics that are of importance to the precast industry. The goal is to disseminate common knowledge, and to increase awareness of similarities and differences of both approaches.
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