3.1.1. Extruder

Buildings of this type have the same cross section for their full height. An example can be a rectangular or cylindrical solid (Figure 1a). Within this group the following modifications may exist:


**Figure 1.** Extruder type of high-rise buildings: (**a**) Marina City towers (Chicago, cylindrical central core system), (**b**) Bay Gate (Dubai, wall frame system), (**c**) Doha tower (Doha, tube frame system), (**d**) Greenland Puli Center (Jinan, core and outrigger system) and (**e**) the World Trade Center (Bahrain, shear wall frame system), figure by authors.
