Design approaches against wind excitation - Tall Buildings: Structural Systems and Aerodynamic Form - page 160

Examples of buildings with tapering include:

• John Hancock Center (Chicago, 1969) ( Figure 6.5g )
• Chase Tower (Chicago, 1969) ( Figure 6.6 )
• Transamerica Pyramid (San Francisco, 1972) ( Figure 6.7 )
• Shanghai World Financial Center (Shanghai, 2008) ( Figure 6.5c ).

Buildings in which setbacks have been used to reduce the plan area:

• Petronas Twin Towers (Kuala Lumpur, 1998) ( Figure 6.5d )
• Bank of China Tower (Hong Kong, 1989) ( Figure 6.5f )
• Willis Tower (Chicago, 1974) ( Figure 6.5e )
• Burj Khalifa (Dubai, 2010) ( Figure 6.5a ).

Among these examples, aerodynamic form played an important role in the architec-
tural design of the Burj Khalifa from the earliest stages of the design (Irwin and Baker,
2006).
The Taipei 101, completed in 2004 ( Figure 6.5b ), is an example of the use of both
setbacks and tapering. However, since the facades are tapered outward, in the form
of repetitive modules, setback formation does not cause a reduction in the plan area
toward the top of the building.
Varying the plan by changing the plan shape at various levels throughout the height
of the building causes a corresponding change in the vortex shedding effect, which
disorients the across-wind vortices and breaks up their organization (Irwin, 2009).

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Figure 6.5

Some examples of buildings with tapering and setbacks