Bending and torison of doubly symmetric core shear walls

Abstract A theoretical and experimental investigation of the flexural and torsional properties of doubly symmetric core shear walls, with lintel beams providing bracing across the openings at each storey level, is described. Such structures are used in tall buildings to support gravity loads and to resist horizontal forces induced by wind and earthquakes. The theoretical model developed is based on an equivalent closed section and is consistent with established open section and closed section behaviour at the two extremes of bracing. For intermediate bracing, the model incorporates the influences of bending and shear deformation of the bracing beams, out-of-plane bending of the side walls and continuousshear flow around the contour of the assumed equivalent closed section. The theoretical model is validated by a series of tests on perforated aluminium tubes, covering a wide range of lintel beam and effective side wall stiffnesses. The results indicate clearly that side wall distortion can reduce the torsional stiffness of such sections very significantly.