ABSTRACT
The braced tube system developed in the mid-20th century is a very efficient structural system for tall buildings. The diagrid system prevalently employed for recent tall buildings of the 21st century is another very powerful structural system for tall buildings. Both systems carry lateral loads by axial actions of the primary structural members. This paper investigates comparative structural efficiency of the conventional braced tube and more recently developed diagrid system employed for tall buildings of various forms. Structural design of tall buildings is generally governed by lateral stiffness. Tall buildings of various heights are optimally designed with braced tubes and diagrids to meet the lateral stiffness requirements. The comparative structural efficiency of the two systems employed for conventional rectangular box form tall buildings is studied first. The study is further expanded to investigate the structural efficiency of the two systems employed for recently emerging complex-shaped tall buildings, such as twisted and tilted tall buildings. Based on the design studies, comparative structural efficiency of the braced tube and diagrid structures of each form category is presented.
