ABSTRACT
Structural systems for tall buildings have undergone a dramatic evolution throughout the previous two decades and into the 2010s. Developments in structural form have historically been realized as a response to emerging architectural trends in high-rise-building design. In the 1980s, international style and modernist high-rise designs, characterized by prismatic, repetitive vertical geometries and Šat-topped roofs, were predominant. The development of the original tubular systems for tall buildings was indeed predicated upon an overall building form of constant or smoothly varying prole. The rigid discipline of the exterior tower form has since been replaced in many cases by the highly articulated vertical modulations of the building envelope characteristic of the present day high-rise expressions. This general discontinuity and erosion of the exterior façade has led to a new generation of tall building structural systems that respond to the more Šexible and idiosyncratic requirements of an increasingly varied architectural esthetic. Innovative structural systems involving megaframes, interior super-diagonally braced frames, hybrid steel and high-strength concrete core and outrigger systems, articially damped structures, and spine wall structures are among the compositions, which represent a step in the development of structural systems for high-rise buildings.
