Structural integrity and progressive collapse in large-panel precast concrete structural systems

Multistory buildings using large-panel concrete construction have been the subject of considerable interest and research in the past. These systeras combine economical, shallow, hollow-core floor slabs with large precast concrete wall panels to from a complete system that shares the markets for hotels, motels, and multifamily housing. The general arrangement of the load-bearing walls may be cross walls or spine walls. In the early development of multistory, large-panel concrete buildings, the primary loads considered in the design were gravity and wind. With the sustained gravity loads often providing ample resistance 10 the wind loads and the ability to accommodate the small eccentricities of the floor loads, detailing often relied on friction capacity alone for load transfer in grouted joints. However, a gas explosion in 1968 in apartment building at Ronan Point in London, U.K., focused attention on the need to address abnorrnal loads in the design of these systems. The Portland Cement Association conducted research in the 197Os under the sponsorship of the Departement of Housin and Urban Development on the structural integrity and progressive collapse resistance of large-panel buildings. The overall program objective was to develop minimum criteria for the design and construction of large-panel concrete structures. This paper is written as a review of structural integrity and progressive collapse in-large-panel precast concrete systems in the context of 21st-century revaluation of acceptable risk and abnormal loads.