Outrigger Design for High-Rise Buildings by Hi Sun Choi

The Council on Tall Building and Urban Habitat’s Outrigger Working Group has addressed the pressing need for design guidelines for outrigger systems with this guide, now in its second edition, providing a comprehensive overview of the use of outriggers in skyscrapers.

This guide offers detailed recommendations for analysis of outriggers within the lateral load resisting systems of tall buildings, for recognizing and addressing effects on building behavior and for practical design solutions. It also highlights concerns specific to the outrigger structural system such as differential column shortening and construction sequence impacts. In this edition, a new chapter explores the use of “hybrid” outrigger systems that can “tune” the stiffness of outrigger trusses, use leverage of the outrigger arms to drive non-linear damping devices, and use “yielding” materials that absorb seismic energy.

Several project examples are explored in depth, illustrating the role of outrigger systems in tall building designs and providing ideas for future projects. The guide details the impact of outrigger systems on tall building designs, and demonstrates ways in which the technology is continuously advancing to improve the efficiency and stability of tall buildings around the world.

The new second edition features updated design considerations to reflect current practices, Expanded systems organization and examples, and updated recommendations and suggestions for future research.