Analysis of Multioutrigger‐Braced Structures

Abstract

An approximate method is presented for the analysis of multioutrigger structures subjected to lateral forces. The discrete set of outriggers is smeared over the height to give an equivalent uniform connecting medium between the central core and the perimeter columns. The equations of equilibrium and compatibility yield a second-order governing differential equation, which, when solved, leads to closed-form solutions for all forces and deflections, independent of the number of outriggers. Particular attention is focused on two important design parameters, the maximum drift at the top of the structure, and the maximum base moment in the core. Comprehensive design curves have been produced to show the variation of these two quantities with two generalized parameters that define the relative stiffness of core, outriggers and columns. Comparisons between these results and those from a flexibility analysis indicate that the approximate method can give reasonably accurate results for even a very small number of outriggers.