What forces affect skyscrapers?

Answer 1

Skyscrapers must be designed to withstand all the same forces in a shorter building: vertical loads (ex: gravity, snow, the weight of the building itself) and lateral loads (wind, earthquakes).

However, because of the slender proportions, some of these forces become more critical in skyscrapers. for example, wind blowing on a high rise that is asymmetrical in cross section might cause the building to "twist". This torsion can cause dramatic problems with the cladding and windows on the building.

Similarly, high winds at the top of the building create a suction force on the side of the skyscraper not facing the wind. This suction force can become so great that windows will actually pop out if not designed correctly!

Tall buildings must also have special ways to deal with earth quakes. As the ground beneath the skyscraper slides back and forth, the top of the building will tend to sway in reverse direction - almost like a whip. Structural engineers must control this by enormously complex calculations and designs.

Even when a high rise is designed to safely resist all loads, they still must provide an atmosphere pleasant to the occupant. For example, a very slight sway in the top floors of a building (due to normal wind) might make people motion sick, and/or too scared to focus on work!

Skyscrapers are obviously much heavier buildings that shorter buildings with the same "footprint". Thus, the foundations under the building must be more advanced and more capable of withstanding such intense force.

Other forces that must be dealt with include air pressure differentials between inside and outside, and top to bottom.

A final example includes the design of Plumbing systems to provide sufficient water pressures to floors that are very high up.