Episode 123 – Dreams of Richter

Fun fact (based on a presentation I attended given by the church engineer): the faults in Utah have the capacity to make an earthquake just as strong as faults in California. But it’s not likely they ever will. Can we trust that analysis? With God, anything is possible. Even knocking a trumpet out of a statue’s hand due to ground shaking.

The building code doesn’t ensure that your building will be ready to continue operation after the level of earthquake that you design for happens. It’s aim is public safety. They shoot for a small percentage of collapse (I forgot, 1% or 5%) after a design level earthquake. If it’s a hospital or a building that has hazardous materials, the design load factor is 50% more than your typical building because those need to be operational after the shaking stops. It’s all about determining what’s likely to happen statistically. It would be super expensive to demand every building be designed for the biggest earthquake possible, especially for commercial buildings. But you have the freedom to design your building for higher loads than the low bar set by the building code. If I remember correctly from that presentation, the LDS church is having the temple renovations designed for the highest likely earthquake. If the trumpet being knocked out of the hand was a warning and not just a cute coincidence then can’t God be like, “Challenge accepted!”

For a typical house it wouldn’t cost much more $ to design for a much larger earthquake demand. But contractors pinch every penny. For example, my family room floor is really bouncy. If they would have just added 1 or 2 more joists then I’d have a much more firm floor. I’d be willing to spend $100 more dollars for a firm floor.

But just because your building is designed for the highest load doesn’t mean it will be able to resist it. And even if you’re designed for a lower load you might luck out and have much more capacity. Lots of things aren’t engineered to the edge of the code required loads. There’s always room for jello and there’s probably room for a little more resistance. Then again, there’s probably not. I saw a presentation on that Florida tower that came down. It all started with the outdoor pool deck slab over the parking garage coming down. That progressed over to the building and something happened to bring the whole thing down. The slab was too thin to even handle the dead loads yet it still hung on for a long time. There’s a detailed presentation on it by the Miami Herald I believe that explains it. The engineer professor who did the analysis for the article presented her findings to Utah engineers in February. Fascinating but sad. For a more detailed analysis on what went wrong, NIST is on the case . Have I been rambling enough? Has anyone made it this far? I actually wrote this and didn’t have an AI write it for me.