Tier buildings with shear cores, bracing, and setbacks

Abstract

The theory of bending and torsion in thin-walled members of open cross section is applied to shear cores included within the analytical model of the tier building. Representative types of bracing arrangements are also considered and their stiffnesses augment those of the beams, columns and shear walls. Changes in floor plan, referred to as “setbacks”, further complicate the analysis; but a relatively simple routine allows automatic handling of this characteristic. Computer programs named STATIER and DYNATIER include all of these features within the linear static and dynamic analyses of three-dimensional multi-story buildings. Results for a twenty-story structure demonstrate the significance of the interaction between a shear core and the skeletal framing. The effect of warping restraints upon the stresses in the shear core is large at the base but diminishes rapidly with height. The normal stress at the base associated with the bimoment is of the same order of magnitude as that due to the combination of biaxial bending and axial force.