Bill Burton: It's time for us to take a look at the Science Behind the Forecast, as I am joined by WAVE 3 meteorologist Tawana Andrew. Good morning, Tawana.
Tawana Andrew: Good morning. Today's topic has a lot to do with very important infrastructure that we use every day.
BB: Yes, and we may unsettle some folks, but as I like to say, knowledge is power. We're going to be talking about how the weather and climate change can play a role in bridges and overpasses and how they deteriorate. Explain, please.
TA: So of course, you know me. I'm going to dive into the numbers. And I found, I found that of the more than 600,000 bridges in the US, about 7% of those bridges are deemed structurally deficient. That means they're basically in poor condition.
Now for Kentucky, 7% of our 14,000 bridges are deemed structurally deficient. And in Indiana, that number is 5% of the more than 19,000 bridges across the state of Indiana. Now to switch things and put things a little bit more into context, 42% of bridges in Indiana and 27% of bridges in Kentucky are deemed in good condition. So with that information, I was like, "How does weather, of course, play a role in this?"
Now, I looked into what makes a bridge as strong as it is, and for a lot of bridges, they have basically these expansion joints that are embedded into the steel and pavement. And they're built this way because it allows bridges to contract and expand with general temperature changes. Now, if we start to see increased temperature spikes, like what we see like a year like this, where we have record breaking heat across the entire world, this can lead to expansion joints swelling more dramatically and more often, and when you have these joints expanding even more around the debris that typically accumulates in these areas, it could lead to the steel deforming the bridge that cracking and moisture even infiltrating the bridge itself and causing corrosion.
Now also, with the wild temperature swings, you can end up with pavement actually squeezing on portions of a bridge span, and that can cause the bridges, steel or a road to buckle and crack, and steel beams can be pushed out of alignment. Thankfully, this is not an instantaneous issue. You don't have to panic about it. This is a slow and steady process that, of course, people who are inspecting these bridges should and will see as they look at it as we get over the next decade or so.
BB: I sure hope so.
TA: I really hope so myself, also we have heavy precipitation and higher water levels that could lead to corrosion on bridges. We saw this in eastern Kentucky, across our and also in parts of North Carolina as well. We saw how higher precipitation and flooding can wash away a bridges foundation. So that's technically called bridge scour, the erosion of sediment around the bridges foundation was found to be the leading cause of bridge failures in the US between 1989 and 2000.
It actually led to the collapse of the I-90 Bridge in New York State in 1987 that was after record breaking rainfall. So the heavy rain also plays a role in all of this as well.
This transcript was edited for clarity
