First off, everyone needs to understand that strong winds and tornado winds are in completely different classes.
Fortunately, there is a phenomenon called the heat island effect that tends to steer wind events such as tornados away from areas with skyscrapers. Basically, areas, where we build such structures, are also accompanied by large areas around them covered with concrete or asphalt. This creates areas of heat being released back into the air, much more than grass, dirt, or most normally encountered naturally occurring surfaces. In order for a wind event to move into this area, which is quite large and with skyscrapers more or less in the middle, the system has to expend more energy to move in that direction. As such, there needs to be a lot of factors working against you for a tornado to run into a skyscaper.
Skyscrapers are designed to withstand high winds far and away beyond the highest wind recorded in that area. There two areas of concern in the case of a tornado hitting a skyscraper. First, weak or brittle structures, such as glass, are likely to break apart from the shock. This opens the building up allowing for forces to be applied to the structure that were never intended by its designers. Second, the sheer magnitude of the wind can cause force-multiplying effects that were not considered as the likelihood of the situation was too remote.
Just as a side statement. It isn’t the goal of building designers to keep the building safe in all situations. The goal is to keep the structure sound enough to allow the occupants to escape.
Most skyscrapers have a large glass area allowable due to the structural frame tending to be internal. The problem here is that occupants that weren’t in a protected part of the structure, such as the stair or elevator cores, are not only subject to the full force of the tornado, but likely tunneling or vortexing action which would intensify the wind speed and pressure within the structure. This would be like a car crash occurring everywhere within the building. People, furniture, partition walls, anything except for the cores stand an excellent chance of being swept out of the building. Anyone in the cores would experience large pressure swings likely sufficient to buckle doors making the problem worse. A lot of these people would find themselves being thrown down at least one set of stairs to the next landing.
The frame of the building will likely do fine as it has a much smaller profile than the whole building so collapse is relatively unlikely.
The only saving grace in this scenario is that the tornado would move through the building quickly, about the speed of a car. Once past the wind force drops immediately back to high winds or less. So, if the initial blast hadn’t pulled you from the building it is unlikely to do so at this point. But, you’re still in the debris field except that you are no longer protected from it by the skin of the building, and there are many loose objects around you.
You would need to find cover as best as possible until the winds died down to a manageable level, which should be in the next few minutes. Now you’ll need to work on getting those stair doors open and getting down to street level.
Rejoice, kiss the ground, you just survived one of Earth’s little miracles.
Remember that once a tornado passes through an area you need to be very aware of your surroundings as many things have become unstable and dangerous.
MKDesign 