Multistory buildings using large-panel concrete construction have been the subject of considerable interest and research in the past. These systems combine economical, shallow, hollow-core floor slabs withlarge precast concrete wall panels to form 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 to 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 an apartment building at Ronan Point in London, U.K., focused attention on the need to address abnormal loads in the design of these systems. The Portland Cement Association conducted research in the 1970s under the sponsorship of the Department of Housing 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 reevaluation of acceptable risk and abnormal loads.
