“The proportion of height to width in the tall blocks indicates the need to place at least part of the load- bearing structure round the periphery of the building, on the same principle as is familiar in a chimney or simple tower.”
Chamberlin, Powell & Bon, Architects “Barbican Redevelopment” April 1959
The tower blocks were constructed on the same principle as the Victorian industrial chimney. The load-bearing structure is mainly round the outside.
The problem -not faced by chimney designers – was how to combine an outer shell with the requirement for windows. It was solved by using a network of pre-cast frames of reinforced concrete, which together form a monolithic framework over the entire face of the buildings.
The vertical structure is formed by the inner core of lift shafts and stair wells, with a system of split piers and beams round the perimeter. This structure provides the necessary lateral stability against wind-forces and support for the vertical weight. Direct overturning forces are resisted by the inner core. Rotation forces caused by the non-coincidence of the centre of pressure and the centre of reaction are resisted by the outer system of piers and beams. I’m quoting – I’ve absolutely no idea what that actually means!