Bomb Blast Engineering for Entrance Hall at Blackfriars Station
London’s rail infrastructure has received massive investment to ensure that it can meet the challenges of the 21st Century. This has led to several huge projects over the last decade, one of which was Network Rail’s ‘Thameslink Programme’ to improve passenger flow through central London.
Blackfriars was one of the stations included within the programme, and its upgrade included platform extensions, and the provision of a new entrance hall, with a large, curved, glazed façade.
The station (left) with Architectural Vision (right)
MMI, working through their client, were responsible for the bomb blast engineering of the new entrance hall façade, including blast hazard modelling, glass specification, design of supports, and confirmation of acceptable dynamic response of the supporting mullions and trusses. MMI also provided advice on other glazed systems around the station upgrade.
In undertaking blast hazard modelling analyses, MMI converted 3D models of the entrance hall into CEBAM, which provided details of the external and internal blast load time histories.
MMI worked closely with their client and a glass supplier to investigate the blast performance of planar glass, which uses point fixings at the panel corners. Despite initial concerns regarding the possible poor performance of such systems, MMI made use of historical blast test data to confirm that a suitable level of protection could be provided subject to a number of design enhancements, such as increased glass thickness, enhanced fixings, and the use of external caps/structural silicone sealing.
Once the glass performance had been understood, MMI developed suitable Finite Element (FE) models, which were validated and integrated with representations of the supporting structural system. Specifically, the glass was modelled along with mullions, assuming rigid trusses. However, the trusses were then also verified to withstand the mullion reactions.
The peak reactions at the various connections within the system were extracts and used to support hand calculations to demonstrate that the connections were strong enough.
MMI worked closely with their client and leading UK glass supplier to develop a safe solution, which met the expectations of Network Rail and its security advisors.
For more information surrounding our bomb blast engineering capabilities and work within the Security Sector, please contact us on 01925 230 655 (Warrington) or email us.