(13 July 2011)

Some thought it was the building that couldn’t be built. But now, three years and 7,800 tonnes of steel later, Cannon Place has won a Structural Steel Design Award for its “heroic concept and striking appearance.”

The awards, which are sponsored by the British Constructional Steelwork Association, recognise high standards of structural and architectural design in the use of steel. The judges were particularly impressed with the way in which the project overcame site constraints and the challenges of constructing an eight storey office block above the busy Cannon Street station.

In total, Cannon Place contains around 7,800 tonnes of steel with four central cores from which the northern third and southern third of the office floors are suspended. The 21m cantilevers are supported via large exoskeletal cross frames back to the cores which in turn are tied together via similar cross frames to enable the whole structure to balance. The north cantilever supports the south and visa versa.

During construction, twenty two 300 tonnes strand jacks and over 10,000m of steel cabling were utilised to construct the cantilevers due to the railway infrastructure beneath. Over 2,000 tonnes of temporary steelwork has also been employed on the project to enable both stations to remain open during the construction process.