Historical review of prescriptive design rules for robustness after the collapse of Ronan Point

After the collapse of Ronan Point tower building in 1968 there was an unprecedented discussion about the issue of progressive collapse in structural design. In particular, recommendations were published that precast panel structures should include tying elements to hold a structure together after an element loss. The initial investigation into the causes of the collapse and the majority of the subsequent discussion was focused on ensuring precast structures had the same monolithic behaviour as conventional forms. However, the prescriptive recommendations were then applied to all structural forms without amendment to account for the different mechanical behaviour. This paper presents the findings from a novel bibliographic study of historical documents published soon after Ronan Point collapse which influenced the development of relevant design guidelines. The technical information was analysed chronologically to determine the intended purpose of such requirements and the assumptions they were based on. It then traces the development of progressive collapse design requirements to the current Eurocodes to consider if they are being applied as intended. This critical review is timely since robustness considerations in Eurocodes and other international codes are currently being reviewed and general misconceptions regarding existing prescriptive rules have been identified among practitioners in the UK and internationally.