Structural Systems of Tall Buildings

The structural system has a great impact not only on exterior aesthetics of a building, but also on its interior space planning. Thus, it must be considered with its structural material, functional requirements, and building shape and form such as the location of columns and bracing, the relationship of columns to the planning grid and the size of the service core.

In addition to its dead and imposed loads, a super tall building must be designed for resisting horizontal wind or seismic loads, whichever is greater. For a building located in a seismic area, even when wind forces govern the design, structural connections must also be designed to absorb seismic energy.

1. Taipei 101- 509 m tall - 101 floors -Taipei: The structural system primarily comprises eight 3 x 2.4m steel box section mega-columns filled with reinforced concrete up to level 62. Main floor girders connect each mega-column with a core corner column, forming a ticktack-toe board. The square-shaped core comprises 16 box section columns, which are fully braced between floors. Outriggers connect mega-columns and the core at every eighth level.

2. PETRONAS Towers 1 & 2 - 452 m tall-88 floors- Kuala Lumpur: The structural system comprises high-strength reinforced concrete perimeter columns and ring beams which are tied with a reinforced concrete central core by a 2-storey deep outrigger truss. Typical floor system consists of wide flange beams spanning from the core to the ring beams with a composite metal deck with concrete topping.

3. Jin Mao Tower - 421 m tall- 88 floors - Shanghai: The structural system primarily comprises eight perimeter composite mega columns encased with concrete. The mega columns are linked to an octagon-shaped reinforced concrete core by steel outrigger trusses at three levels and capped with a 3-dimensional steel space frame at the top level. The floor system comprises composite wide flange beams with a composite metal deck with concrete topping floor slab

4. International Finance Centre - 415 m tall - 88 floors- Hong Kong: The structural system primarily comprises eight perimeter composite mega-columns which are encased with concrete and linked to a square - shaped reinforced concrete core by steel outrigger trusses at four levels.

5. CITIC Plaza- 391 m tall - 80 floors - Guangzho: The structural system is based on a tube-in-tube system comprising twenty high-strength reinforced concrete perimeter columns and floor edge beams and an octagon shaped reinforced concrete central core. The beams and floor slabs connect the perimeter columns and central core.

6. Shun Hing Square - 384 m tall- 69 floors - Shenzhen: The structural system primarily comprises a peripheral rigid steel frame and reinforced concrete rectangular central core which are connected by rigid steel outriggers at four levels. The floor plates comprise closely-spaced steel beams and one-way spanning slabs.

7. Central Plaza - 374 m tall - 78 floors-Hong Kong : The structural system is a tube-in-tube system comprising high-strength reinforced concrete perimeter columns at 4.6m centers and 1.1m deep floor edge beam and a triangular-shaped reinforced concrete shear-wall core.

8. Bank of China Tower - 367 m tall - 70 floors-Hong Kong: The structural system is a cross-braced space truss system comprising four concrete encased composite steel mega columns at building corners and one column at centre to resist both lateral loads and almost the entire weight of the building.

9. The Center- 346 m tall - 73 floors- Hong Kong: The structural system primarily comprises twelve steel box section mega-columns and steel outrigger trusses at three levels. The columns are filled with concrete for 20 storeys, then reduce in size and become hollow as they reach the top.

10. Burj Khalifa, Dubai - Over 828 m tall- 160 floors - Dubai ( added for comparison): Designers purposely shaped the structural concrete Burj Dubai - Y-shape in plan - to reduce the wind forces on the tower, as well as to keep the structure simple and foster constructability. The structural system can be described a "buttressed" core. Each wing, with its own high performance concrete core and perimeter columns, buttresses the others via a six-sided central core, or hexagonal hub. The result is a tower that is extremely stiff torsionally. SOM applied a rigorous geometry to the tower that aligned all the common central core and column elements to form a building.

Each tier of the building steps back in a spiral stepping pattern up the building. The setbacks are organized with the Tower's grid, such that the building stepping is accomplished by aligning columns above with walls below to provide a smooth load path. This allows the construction to proceed without the normal delays associated with column transfers. 

References:

1. Economics Planning of Super Tall Buildings in Asia Pacific Cities- by Dr Paul H K HO, Hong Kong SAR, China; papers/ts_4g/ts04g_01_ho_1673.pdf.

2. www.burjkhalifa.ae