Studies on various structural system design options for twisted tall buildings and their performances

SUMMARY Employing twisted forms for tall buildings is a recent architectural phenomenon. This paper studies various structural system design options for twisted tall buildings and their performances based on lateral stiffness. Twisted tall buildings of various heights and rates of twist are designed with different types of contemporary tall building structural systems, such as diagrids, braced tubes and outrigger systems. The heights of the studied buildings range from 60 to 100 stories, and the rates of twist range from 0° to 3° per floor. As the rate of twist increases, the lateral stiffness of the tower decreases. The stiffness reduction rate caused by twisting is very much dependent upon the structural systems employed for twisted tall buildings. While an emphasis is placed on the structural performance of twisted tall buildings, other aspects, such as architectural and constructional issues, are also discussed holistically.