Lateral Load Distribution in Asymmetrical Tall Building Structures

An approximate method is presented for the analysis of the distribution of lateral forces among the components of a three‐dimensional tall building structure that consists of assemblies of shear walls, coupled walls, and rigidly jointed frames, subjected to both bending and torsion. The load distribution on each element is assumed to be represented sufficiently accurately by a polynomial in the height coordinate, together with a concentrated interactive force at the top. The presence of the latter is essential for obtaining accurate results as simply as possible. A set of flexibility influence coefficients, relating the deflection at any level to any particular load component, is established for each element using continuum techniques. Use of the equilibrium and compatibility equations at any desired set of reference levels enables the load distribution on each element to be determined. Good results appear to be achieved for regular structures by using no more than about four reference levels, requiring the use of matrices of no more than order 4 in the analysis.