Individual bracing units: frames, (coupled) shear walls and cores
The bracing system of multi-storey buildings is normally made up of different units: frames, shear walls, coupled shear walls and cores. Local bending is associated with the full-height bending of the individual columns of the frame when the beams purely act as connecting media with pinned ends between the columns. The corresponding stiffnesses are the shear stiffness, the global bending stiffness and the local bending stiffness. The behaviour of frames under lateral load is complex, mainly because they develop a combination of bending and shear deformations. The structure is thirty-storey high and consists of four shear walls that are connected by beams at every floor level. The situation is very simple with shear walls. The formulae derived for the deflection, fundamental frequency and critical load of rigid sway-frames already contain the solutions for shear walls. The frame can be characterised by its local bending stiffness and its effective shear stiffness.