Dear Editor,

There are a lot of tall buildings being built today and there are often lots of stiff walls on the upper floors and few walls and lots of columns on the ground floor.

Unless a competent structural engineer was the designer, there is the possibility of the formation of what in seismic design is called a soft storey.

In an earthquake the earth mostly moves violently sideways, and up and down. If the building has a lower floor with only relatively flexible columns to one side of the lowest floor and stiff walls on the other side, this can cause the building to twist when the earth moves sideways and the floor above tries to stay stationary. Structural engineers can counter this tendency by having strategically placed stiff structures on this floor, such as extra-thick walled elevator shafts.

If a soft storey is not countered in the design, or avoided, it becomes an earthquake sad story when the tops and bottoms of the columns and the few walls fail, and the stiff floors above fall about 12 ft as one block with nothing to cushion it.

Dropping thousands of tons of concrete that far may make even the walls above fail and crush as we have seen in the videos of tall buildings collapsing into piles of rubble in Turkey and Syria. Survivors weeping and wailing. A real sad story.

Howard Chin

hmc14@cwjamaica.com