Disproportionate Collapse in Building Structures.

Abstract

The failure of the Ronan Point apartment tower focused interest in disproportionate collapse, and prompted the ?Fifth Amendment? to the UK Building Regulations which was introduced in 1970. From this point on structures were required to exhibit a minimum level of robustness to resist progressive collapse. These rules have remained relatively unchanged for over 40 years. This paper presents a review of the concepts relating to structural collapse, and the robustness of structures. In general, there are three alternative approaches to disproportionate collapse resistant design: improved interconnection or continuity, notional element removal, and key element design. These techniques are outlined and their shortcomings are described. The treatment of robustness in the Structural Eurocodes is also summarised. The concepts outlined in this paper are not material specific, and therefore can be applied to all materials and types of structures.