column

The columns in a building do the same job as the legs of a chair. When someone sits on a chair, the legs transfer the load from the person to the ground. The chair legs tend to be squashed by this load. Engineers call this squashing action compression.

The weight of the building and things inside it is transferred to the ground by columns acting mainly in compression.

During an earthquake, buildings can sway, pushing down into the ground on one side and pulling away from it on the other side. This causes the columns to bend and work in tension or compression at the same time.