Making Buildings Earthquake Proof

Posted by Maureen K. Fleury Aug 19, 2008

Studies done on making buildings withstand strong earthquakes have usually concentrated on the lateral (side-by-side) movement of buildings. Now scientists are considering the vertical acceleration that occurs during an earthquake.

When an earthquake hits, there is side by side swaying but that is combined with up and down movement. It’s all to do with how columns and beams are reinforced. Scientists have discovered that masonry can handle downward force but does not do well when being forced upward.

Here is what scientists have suggested and buildings have implemented for minimizing the damage from movement in all directions.

• Isolate the building from the ground in order to reduce the vibrations from an earthquake. Instead of having the foundation rest directly on soil or rock, use a material that will provide an cushioning effect and reduce the energy transfer from the ground to the building. One material being studied is fibre-reinforced polymers.
• Counteract the the side-by-side load by installing liquid dampers. These dampers are similar to putting a water tank at the top of the building. This technology is already being used in Vancouver and in other cities to counteract the effect of high winds on high rises.

I felt this multi-directional movement when a mild earthquake hit Vancouver in early 2001. I was sitting at the kitchen table and while I was being jiggled from side to side, I was also being raised up and down. Reminded me of pictures I see of people riding bucking broncos.