Distribution factor method with cubic interpolating correction for analysis of building frames

Abstract

A more accurate approximating method for the analysis of building frames than a previously described distribution factor method is presented. This paper makes corrections on the displacements for very tall buildings where uneven elongations of columns along the height are important. A new distribution pattern in terms of cubic polynomials with an additional ten unknowns per floor is added to the original sets of distribution factors. The total number of unknowns per floor for a three-dimensional building is 22 (9 mixing factors plus 10 coefficients of the cubic polynomial plus 3 horizontal displacements) irrespective of the complexity. Less than 5% errors in the computed nodal displacements are achieved. The method is particularly suitable for microcomputers.