Figure 2. Kingdom Tower Y-shaped plan
Supertall Buildings and Wind
The Y-shaped plan forming the base of the design offered several advantages. A 120-degree separation between wings allows for views to be expansive but not directed toward adjacent units, which would have created privacy issues. A Y-shaped plan would provide a higher ratio of exterior wall to internal area, which would maximize the residential units’ views and exposure to light (see Figure 2).
The “Y” shape also allowed the spreading of the base of the tower without increasing the depth of the lease-span. This means that the building can still maintain a reasonable 10:1 height to width ratio without having a large amount of unusable deep internal space. The “Y” shape also helps develop a clean and simple structural diagram in which every element participates in both gravity and lateral support. If one considers the shape as being similar to a wide flange beam with its mass of structural material at the end of each wing (the “flanges”) where it is most optimally placed, connected by shear walls (the “webs”) forming the corridor walls and core, the structural efficiency is maximized by placing the material where it will do the most good in resisting wind-induced bending loads. The triangular core thus formed by the shear walls is also an optimized shape, very good at resisting wind induced torsion. Lastly, the unique nature of the Y-shaped plan and structure allows for certain serendipitous results. Having three legs, the plan naturally has at least three stairs, creating an immediate redundancy. With its continuous, reinforced concrete shear walls, those stairs are completely enclosed within a very robust and secure environment, again enhancing that aspect of the life safety system of the tower. Furthermore, these very thick shear walls provide more than the minimum required fire separation and are a very effective sound-control mechanism between public corridors and private residential spaces (see Figure 2).
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