The Structural Systems oF Tall Buildings - Tall Buildings: Structural Systems and Aerodynamic Form - page 13

The sTrucTural sysTems oF Tall
Buildings
Structural systems in the early twentieth century buildings were basically designed to
resist vertical loads. Today, thanks to developments in this field and to high-strength
materials, with the increase in the height of buildings and the decrease in their weight,
wind and earthquake induced lateral loads have become the primary loads, especially
in tall buildings, and have begun to pose more of a threat than before. As a result,
for structural engineers, providing the strength to resist lateral loads in tall buildings,
whether wind or earthquake induced, has become an essential input in the design of
new structural systems.
Owing to developments in computer technology, construction materials and
structural design, tall building structural systems have gone far beyond the rigid
frame system of the 12-storey, 55 m high Home Insurance Building (Chicago, 1885)
( Figure 1.2 ), recognised as the first skyscraper, and have today reached a point that
could not have been dreamed of in Le Baron Jenney's time, attaining a level that has
made possible the construction of buildings using outriggered frame systems, such as
the 101-storey, 508 m high Taipei 101 (Taipei, 2004) ( Figure 3.36 ) , and the 163-storey,
828 m high Burj Khalifa (Dubai, 2010) ( Figure 3.30 ).
As the height of buildings increases, the choice of structural system decreases.
While the choice of structural system in low-rise buildings is considerable, the alter-
natives in choice of a structural system become restricted by limitations imposed by
the height of buildings. Therefore, especially in tall buildings, architectural and struc-
tural design should be considered together.
Buildings can be classified on the basis of the materials used in their structural
systems [structural materials of the columns, beams, shear trusses (braces), shear walls
and outriggers] as:
• steel
• reinforced concrete
• composite.