New Street Square

Structural design to manage high-rise load distribution

This landmark commercial development in the heart of the City of London, comprises of five buildings, ranging in height from five to 17 storeys, all positioned over a single basement. These high-rise blocks presented uncommon weight distribution challenges.

Walsh was responsible for the detailed design of the superstructure above ground floor level on all blocks. We recommended a long-span post-tensioned flat slab solution to minimise the structural depth and reduce deflections. At the time of construction this was the largest post-tensioned development in the City of London.

We also carried out a detailed stability analysis to minimise the extent of the walls and chose high-strength concrete for the columns to minimise their size. These lean design principles were able to save our clients money on materials and add value to the project.

The tallest block in this development was over 100m in height. This was slip formed and intentionally built out of plumb to counteract the natural lean. The unique weight distribution of this structure was due to the gravitational loads from the position of the core and the stress levels on the core and columns. We worked closely with the contractors on the design of the slip form cores to successfully manage this situation. Furthermore, we carried out analysis at several stages to evaluate the post-construction movements of the cores prior to the floor plates being constructed.