Earthquake Lessons

I was in communication with a structural engineer, originally from India, after the 1994 Northridge earthquake in California. He, and a group of independent engineers were assigned to examine the Sherman Oaks Galleria, a huge shopping center, that was built using the latest state- of the- art earthquake designs at that time. What they found was a line , about 2 feet above the ground , in the structural columns, under the prefab parking garages, that looked like it was drawn by a laser. He said that everyone understood what they were looking at, but could not believe it. The columns had been sheared at 2 feet off the ground , in place, with no vertical misalignment. After chiseling out the columns, it was found that all of the columns were impaired, steel sheared, and resting upon the lower section, no longer in tact. After speaking with fellow engineers, in a mute tone, the agreed comment was---"HOW IN THE HELL CAN WE ENGINEER OUR WAY OUT OF SOMETHING LIKE THIS??? The forces are beyond what the engineer can plan for. As a Boeing executive said, in Congressional testimony, after a plane crash in Atlanta,due to windshear, in a turbulent thunderstorm that killed many people--Responding to a question by a Congress women that basically asked him ? "Why can't you design a plane that will not have anyone die in an accident""?? He responded-- "-Yes we can Mam'---Unfortunately, we cannot get it to fly"---I think that is a problem with trying to engineer the unknown--We do the best we can , with what we have---The rest is all learning....

This raises a good point. Some new event can come along that exceeds the design knowledge available from past experience. Because of this, it may be inappropriate to find fault with the earlier design.

But then one should study the new information that has emerged, and account for it in future designs, including possible retrofits of older construction.

It should be recognized, however, that money doesn't grow on trees, and that citizens/companies cannot reasonably be expected to shell out vast sums in short times to fulfill new standards. The economic damage from excessive regulations may well outweigh that from rare catastrophic events. Good regulation realizes this; poor regulation does not.