LATERAL STIFFNESS OF CORE/OUTRIGGER SYSTEMS.

Abstract

It is common to increase the lateral stiffness of braced cores by placing horizontal trusses or outriggers from the core to the exterior columns. Outriggers, in effect, apply moments which reduce the rotation of the core at outrigger locations. The smaller rotations at those points in turn reduce the overall sway of the structure. Taranath, McNabb and Muvdi and others have analyzed such systems and have provided insights useful for design. McNabb and Muvdi analzyed the case of multiple outriggers and concluded that the gain in stiffness decreases as more outriggers are added. Herein the case of outriggers at only one location is analyzed. The work presented generalizes the results of the references cited by explicitly considering flexible outriggers, nonprismatic elements and a triangularly distribued lateral load.