Office building at 70 St Mary Axe

70 St Mary Axe, known informally as the ‘Can of Ham’ because of its curved shape, is an office building in the City of London. Rising to a height of 90 m, it has 24 storeys and a footprint of 48 x 40 m. The load-bearing steel structure of columns and floor beams is built around a concrete core that houses all the pipes, lifts and stairs, and the steel skeleton contains almost 3,000 tonnes of grade S355 steel. The columns are a combination of UC profiles and UCs with welded-on plates; floor beams are either welded-together sheet steel girders or UC profiles. The construction technique selected for the floor – the 33,000 m² floor plates are made of 0.89 mm galvanised steel profiled sheets filled with lightweight concrete – meant that it could be walked on within a week. Each floor comprises an average of 100 structural steel elements that took on average 1.5 weeks to assemble per floor. The roof structure is made up of 5 curved composite profiles.