Another Look at Structural Robustness by Yasser Eljajeh

A talk (hybrid) by Yasser Eljajeh, Principal Structural Engineer, RBG on the topic “Another Look at Structural Robustness - How to design efficient structures against disproportionate collapse”
This CPD Session will go through past and current examples showing how design of structures to resist disproportionate collapse should be approached with an award-winning case study project.
This CPD session will start with a brief introduction to structural robustness, followed by an introduction to current international guidance to avoid disproportionate collapse of structures, analysing the gaps in the current design guidance, introducing the new ASCE Standard for mitigation of Disproportionate collapse, and presenting an award-winning case study- The Viadux II Project.
Viadux II is one of the most challenging current projects in Manchester. Due to the level of complexity associated with this project, innovative solutions were essential in the design process.
The overall Viadux development includes the construction of a 39-storey residential tower, 15-storey office building, connecting podium structure, and the conversion of a Grade II listed masonry viaduct. The proposed buildings are to be built over an existing viaduct structure.
This case study discusses the challenges faced during the design of the office building’s transfer truss. As the project is being constructed on top of a Grade II-listed viaduct, minimal penetrations had to be achieved by reducing the number of columns supporting the building. Another restriction to the locations of these columns was a tram line crossing the site from southwest to northeast. With these limitations in mind, 10 columns with spans of up to 34.5m were strategically placed.
Due to the large spans, a transfer truss was needed to help transfer the loads from the structure’s 15 storeys to the columns, making it a crucial aspect of the structure’s loadbearing system. In addition to the reduced number of columns, the need for heavy goods vehicle access to Manchester Central Service Yard dramatically increased the risk of progressive collapse of the entire structure. The risks associated with this building and other high-risk structures were effectively mitigated by the proposed state-of-the-art solutions.