Talking Michigan Transportation

Are we talking enough about crumbling bridges?

• Michigan Department of Transportation • Season 7 • Episode 233

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On this week’s edition of the Talking Michigan Transportation podcast, a conversation with the state’s chief bridge engineer about the dire forecast for bridges without additional funding.

Beckie Curtis, director of the Bureau of Bridges and Structures at the Michigan Department of Transportation (MDOT), explains the stark reality.

  • Bridges must maintain a minimum condition to keep the transportation system open.
  • Bridges are expensive investments in the highway network.
  • Bridges are long-lived assets, and many bridges on the trunkline system were built in a short window of time as part of the interstate and other freeway systems.
  • Because of these factors, combined with historic underfunding, widespread bridge closures can be expected in the next 10-20 years unless funding is increased.
Jeff Cranson:

Hello, welcome to the Talking Michigan Transportation podcast.

Jeff Cranson:

I'm Jeff Cranson.

Jeff Cranson:

I spoke with Beckie Curtis, who is the Director of the Bureau of Bridges and Structures, or BOBS, as they say at the Department of Transportation.

Jeff Cranson:

She has a great deal of experience working on bridges, inspections, overseeing the program and everything that's involved and trying to preserve bridges in a funding-challenged time which we live in and has been a problem for a long time in Michigan as we've underfunded our infrastructure. We talked about how people take bridges for granted even more than roads. Most of us probably don't even realize how many bridges defined broadly, as you know, anything that crosses over another road or a body of water even culverts every day, and what it's going to take long term to shore them up and get a sustainable funding source, as Michigan could be looking to close bridges on the state system in a 10 to 20 year window if we don't do something soon. So I hope you enjoy the conversation, Becky Curtis, who is the director of MDOT's Bureau of Bridges and Structures, or BOBS, as the insiders say. Becky, it's been a while since you've been on the podcast. Thank you for taking the time to be here.

Beckie Curtis:

Yeah, happy to be here.

Jeff Cranson:

So there's a lot of talk now. As you know, there's always a lot of talk about a funding increase for roads and bridges. In Michigan, every level from you know the county roads to the city, roads to the state trunk lines are in need of additional investment. They have been underinvested for decades. There's been some one time fixes, there's been some incremental steps. Certainly, the Rebuilding Michigan Bonding Program that put $3.5 billion into trunk lines was a huge boon, but that's going to run out and while the lawmakers and the governor are working on negotiations, I thought it would be a good time to focus on bridges.

Jeff Cranson:

We think that transportation infrastructure is something people take for granted. People say, yeah, everybody takes roads for granted, but I think they really take bridges for granted. The big ones get our attention, they even get stamped on our license plates. We feel very proud of the Mackinac Bridge, for instance, but we all go over other bridges every day and don't even think about it, and we've got some that are really in bad shape and we're talking for the first time, I think, maybe in MDOT's history about the possibility of having to maybe close some in 10 years in that window, which has never been done. Other states have had to do that because of funding and I just I guess I want you to give your overview and how we got here and what it takes to get out of it.

Beckie Curtis:

Yeah, I think it is a really critical time for us to start talking about bridge funding and a lot of that's going to be tied to the age of the inventory of our bridges. So, when you're talking about bridge condition and bridge funding, there's kind of like four key points. First, you know, especially compared to roads, bridges must maintain a minimum condition in order to keep the transportation system open. So, if a bridge condition drops enough, the owner has to close it to keep the public safe.

Beckie Curtis:

Secondly, bridges are really expensive investments in the highway network. You know they're usually a short segment of the roadway and yet they can be more than the amount of funding that a local agency gets for transportation in an entire year to do a project on them. Third, bridges are long-lived assets, so that's a benefit. We have a lot of opportunity to do preservation, mix and fixes to keep that bridge going. But at the same time, for the trunkline bridges, most of our bridges were built in a short window of time as part of the interstate and freeway system and we're getting to the point where we're seeing the end of the service life of that large population of bridges coming up in the not-too-distant future and being in a position where we don't have the funding to address all of them at the same time. And so, because of all these combinations of factors, you know, combined with historic underfunding, we are predicting, you know, the potential for widespread bridge closures in the next 10 to 20 years, unless funding is increased.

Jeff Cranson:

I wonder if you have a lot of counterparts around the country that you confer with on various committees? There's a lot of peer sharing. Is a major topic of conversation the idea that our forebears had the vision, y ou know President Eisenhower collaborating with then Al Gore Sr, who was the senator who actually carried a lot of the water for the interstate system. Everybody was excited about building these roads and bridges. I wonder if there was enough thought given to what it was going to take to maintain them going forward and how much that would eventually cost, because it just seems like a lot of people don't get that.

Beckie Curtis:

I think that you know in the industry at the time this concept of service life, how long the bridge was going to last. It wasn't even a topic of conversation like we do now. You know you couldn't even use federal funds to do preservation on your bridges until like the 2000s and so we had this. You know large population, this very important interstate system which is important for commerce, built, constructed without a plan for how to maintain it, and it is absolutely a conversation that we're having at the national level. I'm the chair of the Asset Management Technical Committee for the Committee on Bridges and Structures and our technical committee has focused the past year on trying to collect that data. You know, looking at the number of replacements we're doing on the interstate per year nationally and how it really falls short of what's needed to keep the interstate open long term.

Jeff Cranson:

So we wouldn't. I mean, this comes up a lot and you never would call a bridge unsafe. If we thought a bridge was unsafe, we'd close it obviously. We have to make a lot of emergency repairs and some of that kind of masks how bad things are If you get out and get underneath some of the bridges it can be really stark. Talk about how you and your staff have had to be very creative in preserving what we have.

Beckie Curtis:

Yeah, so we are doing our best to manage the inventory and to impact the public and traffic as little as possible while keeping the bridges safe, and so as part of our inspection program, we go out at least every two years. But as a bridge condition declines, we're going to go out at a reduced interval. So more frequently we're going to identify anything we see that could be a safety issue. So that could be concrete that might fall off and fall the traffic below. That could be substructure units that are spalling and need temporary supports. We will flag those as a request for action. We're going to send out, depending on the emergency, we have a statewide bridge crew that will respond to these. Put up temporary supports, w hatever we need to do to keep traffic flowing until we can find the resources and the time to make repairs.

Beckie Curtis:

And with our condition that it is now, we find that we are able to keep up on those critical, we call them critical findings. If they impact traffic that would be a lane shoulder or bridge closure. We're able to keep up on those, however, as our condition deteriorates, we expect more of those to happen, and the more that they happen, the harder it will be to mask those impacts to the public, and they're going to feel it. They're going to have their bridge closed, maybe for weeks to months, until a more permanent repair can happen. And as more and more bridges enter that stage where they have these large issues, eventually we'll have to close them because we don't have the funding to replace all of the ones that we predict will need work in the future.

Jeff Cranson:

It's a little counterintuitive. People think I mean I've actually heard this from people that say "my God, you guys are doing so much, I can't get anywhere. And the Lieutenant Governor, when he gets that question, he says you're welcome. But the same thing that applies to the roads in terms of the need for ongoing maintenance and asset management, because we can't replace that, we don't have the funding to just rebuild them down to the base. And it's the same with bridges, right, You're going to have to do a lot more maintenance, so there's going to be temporary closures, temporary inconvenience, Whereas if you could replace some of those, many of those that just need replacing, then the maintenance intervals wouldn't be as frequent and you wouldn't be as inconvenienced. Is that basically right?

Beckie Curtis:

Yeah, absolutely.

Beckie Curtis:

I think one of the greatest success stories of our bridge inventory is that you know you take that large population of bridges that was built when the interstate and the freeway system went in and while they didn't have an official service life at the time, nationally bridges are being replaced at about 53 years of age.

Beckie Curtis:

So if we say 50 years of age was the average service life of the bridges built when the interstate went in, two-thirds of MDOT's inventory has exceeded the service life already, and the reason why they're still open is because, you know, in the early 2000s we adopted a very aggressive asset management process. We have a mix of fixes. We do preservation on our bridges, and so we are extending the service life of the majority of our bridges beyond what they would have been designed for. So that's a great success. However, we can only do so many interventions before they're not as effective, and so they'll have to continue to happen more frequently, or the bridge is going to have to be replaced, because it's just not economically feasible to continue to patch it and keep it together.

Jeff Cranson:

Stay with us. We'll have more on the other side of this important message.

MDOT Message:

In Michigan. Safety comes first on the roads. To combat distracted driving, Michigan passed the hands-free law.

MDOT Message:

The law makes holding or manually using a cell phone or other mobile electronic device while operating a vehicle a primary offense. This means an officer can stop and ticket you for violating the law.

MDOT Message:

This can include, but not limited to, sending or receiving a call. Sending, receiving or reading a text or email, accessing, reading or posting to social media sites or entering locations into the phone GPS.

MDOT Message:

With this law in place, drivers are encouraged to stay focused, keeping their hands on the wheel and their attention on the road. Drive smart, drive safe, drive hands-free.

MDOT Message:

Michigan's hands-free law making the road safer for everyone.

Jeff Cranson:

Yeah, talk a little bit more about that because I've heard it before but I can't remember off the top of my head. I know there have been calculations by people in our Bureau of Planning that if the 4 cent increase that the legislature agreed to in 98 had actually been 11 cents, indexed for inflation, we would probably have a sustainable funding source. Yet even with that less than enough amount that we got in the late 90s, in the 2000s, bridges were in pretty good condition. How did MDOT pull that off?

Beckie Curtis:

So, yeah, so in 1997, I think, michigan had the second worst bridge condition in the country and by 2007, we'd made like significant increases. I think by 2014, we met our condition goals, briefly, and that was because of the, you know, the increase in funding for bridges and then the focus on asset management. So we had MDOT, had about a thousand poor bridges in 97 and we replaced about a third of those. But two thirds of those of those bridges we address the issues with rehabilitation projects significantly less expensive. You know you can do about 10 rehabs maybe for the price of one replacement and you know, without that mix of fixes, we wouldn't have been able to improve our condition. The problem is is that our funding hasn't increased that much when, meanwhile, inflation's been fighting against us.

Beckie Curtis:

For bridges, we have a measurement we need to submit to Federal Highway. It's unit replacement costs, and so we actually have the data from, you know, from all of the states what is it costing them to replace a bridge? It is really only used for inflation because it doesn't include all of the costs that go into a bridge, but it's a consistent number. S o, from 2018 to 2023, nationally and Michigan was right along in this inflationary zone, it was 13%. So, every year from 2018 to 2023, the cost to replace a bridge went up 13% on average.

Jeff Cranson:

So, I should say you pointed out that it was actually 1997 that the legislature made the move that increased and go into effect until 1998. But the bottom line is we got the curve to where we needed it to be for a while and then it's gradually been falling since then and now it seems like it's falling faster. Talk about how a warming climate factors into this. This is Michigan. Obviously, a lot of our bridges are in the water, and what's gone on with resiliency trying to build for resiliency and climate change presents some other challenges for those bridges right.

Beckie Curtis:

Yeah, so even when we're replacing a bridge, we're going to have to go back with a bridge that's significantly longer. And also, you know, we have a lot of bridges that are, it's called, scour critical. That means that they are susceptible to, in a large flood event, having their substructure exposed and they might need to be closed during a flood event.

Jeff Cranson:

Yeah, explain a little more about scour, because that's a term engineers use, but I'm not sure if everybody knows what that means.

Beckie Curtis:

Yeah, so scour is when you have a flood event. The water in that body of water, it's going to increase speed as it tries to move all that water quickly down to the lake or wherever it's going to come to rest at. And as that water picks up speed, as the levels get deeper, it picks up speed and it starts to pick up the soil that's lining the bottom of that stream. And scour wasn't a design consideration. Remember these are. We have a large population of really old bridges, so we design for scour today, but I still have this old population of bridges that were not designed for scour, and so we have to do special monitoring on them to make sure that, if there is a flood event, that the soil hasn't been removed to the point that the footings are undermined and the bridge can't support itself.

Jeff Cranson:

Yeah, that's well explained. I think that, while you keep an eye on that, and we have to recognize and, this has been the source of a lot of study, that we're going to continue to have more volatile weather events and it isn't just the flooding of the recessed freeways like we've had in Detroit the last several years, even elsewhere in the state that you don't think of those kinds of flooding events being a big problem. The water is just moving faster when you get those kinds of rain events and get that much rain in just a matter of hours. So that's basically what you're saying. That's what creates more pressure on the piers, right?

Beckie Curtis:

Right, yep, the speed and the velocity of the water increases in these large storm events, and it can start picking up the soil and transporting it downstream, leaving your bridge exposed. Up the soil and transporting it downstream, leaving structures, bridge exposed. And consideration, then, designers, because in our older structures scour wasn't a consideration the designers at the time might be restricting the waterway, and so you have this large amount of water moving downstream and all of a sudden there's embankments of the roadway that are narrowing bridge, even further, and so at that pinch point of that bridge the water is going to increase in velocity even more, and so that's the local scour you know, around our substructure units. And so to prevent that, when we replace a bridge we're going to have to span that entire waterway, and that increased costs right. So you might have had a 100-foot bridge and it's going to go back at 150 feet, and obviously that's a lot more expensive to do than if we were replacing it in kind. But of course we would never do that because we know better and we know that to keep that bridge in service long term, we need to address scour.

Jeff Cranson:

told me before that we think that the estimate is probably an additional $400 million a year for trunkline bridges, the state routes and $190 million across the local system. We mentioned that in a 10 to 20-year window we could be actually looking at closing some bridges if we don't get more funding at the state level. But some locals have already had to close bridges and in other places they've had to post them for lower weights than they were originally built to carry. That kind of relates to the bridge bundling program and we haven't talked about that in a while. So could you kind of explain how MDOT helps with bridge bundling to help the local road agencies?

Beckie Curtis:

Yeah. So I think, if I wanted to sum up, the local agency versus the trunk line bridge condition issue on trunk line MDOT, bridge needs are urgent because our inventory is, you know, past the service life and the quantity of bridges that we need to replace in the next 10 to 20 years really needs to be flattened to avoid widespread closure because we can't address all of those bridges at the same time in 10 years. On the local system, their population of bridges is actually a lot younger than ours, but it's urgent because they have such a large number of bridges in serious critical condition. So, to explain that bridges when they're inspected, they're rated on a scale of zero to nine, with nine being new, and poor are those that are four or below, but the four and below is further separated. So, there's three rated bridges which are serious, two are critical and then ones and zeros are basically closed. The local agencies have 14% of their inventories poor and 383 of those bridges are serious or critical condition, and so those are bridges that are really one inspection, possibly away from needing to be closed to having a lane taken, a shoulder closed, something to make sure that we maintain safety through the deterioration and because of that there is an urgent need to replace bridges.

Beckie Curtis:

Now, the Bridge Bundle Program was something that was created to be a potential mechanism, if funding was identified to replace a large number of bridges at one time, where MDOT would provide the technical assistance in getting the bridges designed and contracted and out the door. We have been able to do that fairly successfully. The program, you know, isn't as large as we perhaps envisioned originally, but we have had multiple bridges opened. So to date all of our projects have come in, you know, on budget and on schedule, and we're really happy about that. And then, and most importantly, we were able to successfully compete for a $34 million grant to add even more bridges to the bundle. And, you know, I don't think, an individual local agency would have struggled to have as competitive of an application as MDOT was able to put together on behalf of our local agencies through the bundle program.

Jeff Cranson:

It gets confusing because we talk about state bridges versus local bridges and many states don't have as many road jurisdictions as Michigan. But there are pretty clear lines drawn here that you have counties that own roads and bridges, you have cities and villages that own roads and bridges and then the state owns what we call the state trunkline system. Yet the state, your bureau specifically has a role, responsibility charged by the federal government with helping to keep track of that local inventory. Can you talk about how that works?

Beckie Curtis:

Yeah, so the National Bridge Inspection Standards is the requirement at the federal level and you know there's a lot of different aspects of it, but in general the NBIS is going to require that you have a program to inspect your bridges at the right frequency, that you have a program to low rate your bridges which is identifying the safe you know how heavy a vehicle can cross that bridge safely and then to maintain an inventory. And so, we have to submit that inventory with all that inspection load rating data, and MDOT has oversight of our local agency. So, the local agencies are currently doing their own inspections, their load ratings, either themselves or with a consultant partner, and MDOT is collecting that data and doing quality assurance on it and submitting it to Federal Highway.

Jeff Cranson:

And the Federal Highway Administration asks that pretty much of every state, correct?

Beckie Curtis:

Yes, this is across the country for all structures that are greater than 20 feet.

Jeff Cranson:

Yeah, it's not unique to Michigan. Well, as these talks continue, you'll be watching it closely, as many of us will, to see where we end up, and when you do finally hopefully get an increase in funding, then you'll figure out how to prioritize again, because we can safely say whatever it is, it probably isn't going to completely meet the need, so I guess we just hope for the best.

Beckie Curtis:

Yep, that's part of our asset management strategy is taking the funding that we have and applying it in a mix of fixes to see what we can do to have the lowest life cycle cost. And yet, you know, keep as many bridges open as possible.

Jeff Cranson:

Thank you, Beckie. Always good to talk about this with you.

Beckie Curtis:

Thanks for talking about bridges.

Jeff Cranson:

I'd like to thank you once more for tuning in to Talking Michigan Transportation. You can find show notes and more on Apple Podcasts or Buzzsprout. I also want to acknowledge the talented people who help make this a reality each week, starting with Randy Debler, who skillfully edits the audio, Jesse Ball, who proofs the content, Courtney Bates, who posts the podcast to various platforms, and Jackie Salinas, who transcribes the audio to make it accessible to all.