Parameter Study of Outrigger-Braced Tall Building Structures

The behavior of outrigger-braced tall building structures is studied taking into account the flexibility of the outriggers. Expressions are developed for the core moment distribution, the top drift and the optimum location of the outriggers for minimum top drift. A characteristic non-dimensional parameter is developed that takes into account the core-to-column and core-to-outrigger flexural rigidity ratios. Graphs are plotted as functions of the characteristic parameter which allow the determination of the optimum outrigger levels for minimum drift and the corresponding core base momnet for structures with up to four outriggers. The study is based on the assumption of a uniform structure and uniform horizontal distributed loading.