So you're fighting nature. Yes. And what you're doing there, is you're really taking on whatever the motions are. And the earthquake has a very interesting characteristic to it. It's like a musical, effectively. It's got areas where there's a lot of energy, which is at the frequencies that are very, very low or very, you know, very, very high. Excuse me. And then that's where you're getting the most energy. And then as you get the structure to be more flexible, that's where the energy gets smaller. So if you are a little bit careful about it, you can actually design your structure to be in the areas where the earthquake is less damaging. And by making that structure tuned to what Mother Nature's going to apply, you actually avoid that ground of the force. The other aspect of it is designing components, if you will, that are made to take on the damage. Like when we drive cars. If you think about it, cars - we know we drive cars. We know that we'd like not to get into accident, but we planned for that accident. And the idea... It's like crumple zones. Exactly. And the idea behind it, is you get the damage to occur in areas where you keep the car functional to the extent possible when it's a midsized type of accident that you have. And the idea is that the fenders take all the damage. Very similar to that, is our bridge is designed that way. We actually looked at specific areas which we said that's where it makes sense to have the damage occur. We designed those elements to take on that damage, and thereby protecting the more important elements to it.
So you can replace those damaged pieces later on. Exactly. The idea is that, after an event, the bridge is still functional. We would go in - obviously, the engineers at that time would go in and do a, you know, an inspection, evaluate - there will be damage, but it will be in a form where you can actually make it available so that emergency traffic can be - immediately after that, go on it, and shortly after that go through normal traffic. Mm-hmm. Let's see if we can get some questions from our audience here. Yes, sir. Yes, sir. I remember when the Bay Bridge was starting, and it was meared(ph) with a lot of, like, scandal about bad welds. And how's that being addressed? Did they have to start over, or was the cost overruns and things like that? Well, I'm not sure I follow the specific event. But in general, this question goes back to quality, if you think about it. And one of the issues that is great of our engineering profession is that we basically have design codes. We have standards and we have qualification for quality and assurance that we follow. And the idea behind it is that every weld, every material that we have, is inspected either during the fabrication or prior to using that material, that it satisfies those qualities. And if it's not satisfying them, it gets rejected, it gets pulled out. There is a sense that when you sometimes find something that wasn't good, that you - we did something wrong - and, in fact, it's the other way around. If you think about it, it's the due diligence that we do that uncovers those situations, so to speak.
I'm Ira Flatow. This is SCIENCE FRIDAY from NPR, talking with Doctor Marwan Nader. We talked last week on - a couple of weeks ago on the show about the Brooklyn Bridge. And it turned out that Roebling who had designed the Brooklyn Bridge discovered that it was being made with substandard steel cabling on it, and he had designed so much redundancy or overload into it that it went from 10 times it capacity to only six times what it can hold. I imagine you need to do some, sort of, like redundancy in the bridge.
And you're so right about that. It's an engineering intent. What you do is you look at, sometimes, the situation you're faced with, and you look at if there's a need to perform what we refer to as, does this particular element satisfy the design intent? And thereby, do you really need to go in there and do work to it, or is it OK the way it is?And it's been designed to last 150 years, which is a lot longer than Spotlight Housing.Yes are designed to last. What are the design features helps in that longevity?
So you can replace those damaged pieces later on. Exactly. The idea is that, after an event, the bridge is still functional. We would go in - obviously, the engineers at that time would go in and do a, you know, an inspection, evaluate - there will be damage, but it will be in a form where you can actually make it available so that emergency traffic can be - immediately after that, go on it, and shortly after that go through normal traffic. Mm-hmm. Let's see if we can get some questions from our audience here. Yes, sir. Yes, sir. I remember when the Bay Bridge was starting, and it was meared(ph) with a lot of, like, scandal about bad welds. And how's that being addressed? Did they have to start over, or was the cost overruns and things like that? Well, I'm not sure I follow the specific event. But in general, this question goes back to quality, if you think about it. And one of the issues that is great of our engineering profession is that we basically have design codes. We have standards and we have qualification for quality and assurance that we follow. And the idea behind it is that every weld, every material that we have, is inspected either during the fabrication or prior to using that material, that it satisfies those qualities. And if it's not satisfying them, it gets rejected, it gets pulled out. There is a sense that when you sometimes find something that wasn't good, that you - we did something wrong - and, in fact, it's the other way around. If you think about it, it's the due diligence that we do that uncovers those situations, so to speak.
I'm Ira Flatow. This is SCIENCE FRIDAY from NPR, talking with Doctor Marwan Nader. We talked last week on - a couple of weeks ago on the show about the Brooklyn Bridge. And it turned out that Roebling who had designed the Brooklyn Bridge discovered that it was being made with substandard steel cabling on it, and he had designed so much redundancy or overload into it that it went from 10 times it capacity to only six times what it can hold. I imagine you need to do some, sort of, like redundancy in the bridge.
And you're so right about that. It's an engineering intent. What you do is you look at, sometimes, the situation you're faced with, and you look at if there's a need to perform what we refer to as, does this particular element satisfy the design intent? And thereby, do you really need to go in there and do work to it, or is it OK the way it is?And it's been designed to last 150 years, which is a lot longer than Spotlight Housing.Yes are designed to last. What are the design features helps in that longevity?
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