Bridging the Gap: An Analysis of Proposed Evacuation Links at Height in the World Trade Center Design Competition Entries

Abstract

The 9/11 collapse of the World Trade Center Towers has created the largest single retrospective analysis of tall building design in the past 40 years. In no field is this more relevant than in the field of evacuation. The case for an ‘alternative’ design solution for tall building evacuation—allowing horizontal evacuation at height through skybridge linkages—has already been made. However, to many people—and despite the real advantages as exemplified in built examples such as the Petronas Towers—the skybridge seems a purely fantastical proposition, with no relevance beyond isolated, one-off scenarios. This paper analyses the skybridge links of the numerous re-design proposals for the World Trade Center Towers, with the aim of establishing their advantages and how they could be incorporated into tall building design in the future.