The development of the lean-core + blade-wall system grew out of a brief to create a new high-rise living typology that was lean, flexible and driven by a standardized, prefabricated approach. The objective was to reduce reliance on the central core for stability, allowing the core design to be lean in terms of the size and thickness of walls. This drove the need to develop a supplementary stability system that could be integrated into the required residential brief.
To achieve this, the team researched using an outrigger system to mobilize the full stiffness of the tower footprint, but instead of dedicated outrigger floors, all the reinforced-concrete flat slabs act as outrigger arms, mobilizing the perimeter structure. The key to this unique system is that it relies on the concrete that is already required for vertical loads (i.e., there is no increase in slab depth). This makes the “typical frame” work harder and provide multiple functions. An arrangement of four internal concrete blade walls provides buttressing to the central core, while every floor slab acts as an outrigger, engaging eight perimeter blade walls. The framing system works holistically, as all elements contribute to both lateral stability and vertical support. The system was first deployed at the 80 Newington Butts residential tower, which is expected to complete construction in 2018.