AASHTO re:source Q&A Podcast Transcript

Season 3, Episode 21: Resiliency, Ultra-High-Performance Concrete, and the Future of Bridge Construction

Recorded: September 16, 2022

Released: September 27, 2022

Host(s): Brian Johnson, AASHTO Accreditation Program Manager and Kim Swanson, Communications Manager, AASHTO re:source

Guest: Dr. Atorod Azizinamini, the Director of Infrastructure and Sustainability at Florida International University in Miami, Florida

Note: Please reference AASHTO re:source and AASHTO Accreditation Program policies and procedures online for official guidance on this, and other topics.

 Transcribed by Kim Swanson and MS Teams.

 [Theme music fades in.]

 [00:00:00] Announcer: Welcome to AASHTO resource Q & A. We're taking time to discuss construction materials, testing, and inspection with people in the know from exploring testing problems and solutions to laboratory best practices and quality management, we're covering topics important to you. 

[00:00:20] Brian: Welcome. AASHTO resource Q&A. I'm Brian Johnson.

[00:00:24] Kim: And I'm Kim Swanson. And who do we have with us today, Brian?

[00:00:27] Brian: Well, today we have a special guest, Dr. Atorod Azizinamini, Director of the Infrastructure and Sustainability Department at Florida International University in Miami, FL. Atorod. Welcome to the podcast.

[00:00:42] Atorod:  Thanks for the opportunity to be with you.

[00:00:44] Brian: And now before we get started with questions, I just want to introduce our audience to the concept we're going to talk about today. The term is becoming more and more popular in civil engineering in that term, is resiliency. To me, this term represents recognition that engineers need to now design not just for conventional purposes or applications anymore.  Engineers need to design for potentially catastrophic events, such as, you know, 100-year flood, hurricanes, rising sea levels, extreme temperatures.  And it really doesn't seek to determine why these things are happening, but instead just the understanding that these things are happening and that engineers need to design around them to protect or make the infrastructure more resilient, hence the term. Resiliency. But that's just my layman's explanation of what this is for our audience. But we have our special guest here who is an expert who can probably give us a better definition. So, Atorod, how would you define resiliency?

[00:01:53] Atorod: I think there has been many different definitions of the resiliency. But really resiliency means that, you need to design the buildings and the constructed facility so that they can return to the full function that they were designed originally. Soon after the extreme events like a hurricane for example, let's say, or the flooding that you can have. In our case, let's say in the coastal area where we are dealing with the salt water and the corrosion issue, really the resiliency means that to be, in my mind, is to be proactive and do whatever that we can do so to prevent the damage. Because if you have a damage, it's going to take a time before you can repair it and then return the building or the constructed facility back to the full functionality. So in in my mind, in the coastal area. Especially where we have the hurricane or so on really to be a proactive and do whatever that we can do to beef up or upgrade the existing constructed facility so that they don't sustain a damage. That's the best way to really to return it back to full functionality immediately means that there is no damage because once you have a damage, it's going to take time to repair it. And that's and it's going to paralyze the economy and the functionality and the people's daily life.

[00:03:16] Brian: Absolutely. Now you've been at this for quite some time, right? Working in this field, what first got you interested in this?

[00:03:24] Atorod: You know, I think more than anything else, probably because of the location, Miami, I mean, Miami is a Ground Zero when it comes to the issues related to the resiliency. I've been here since January 2011, fortunately we haven't had a major hurricane that has hit there for example, the area. But there's a lots of preparation that goes, people get really concern about, for example, when there's a prediction that that is of a, let's say, major hurricane that's coming. So continuously we think about that from or sometime in the June to the November 9th of December seemed like the period that we have to be concerned about the hurricane is really increasing. So, I think it's more has to do with the probably where I'm at and I've really have paid more attention to the concept of the resiliency and designing the constructed facility for resiliency since I've been in Miami area.

[00:04:23] Brian: Yeah. Now when it comes to this topic, the items that make the headlines are the building collapse, the bridge getting washed out or the road getting washed out. But you touched on an issue that I think the traveling public doesn't think about a whole lot which is corrosion. What is the impact that you know...Well, you did mention the, you know, the water covering these structures is going to lead to corrosion. But what really happens that's so damaging about corrosion and how long can it take for the negative outcome to occur when corrosion begins?

[00:04:56] Atorod: Yeah, you know the corrosion issue.  First of all, we as a structural engineer we are very good. That's a way of background to tell you we are extremely good if we say for example, give me a beam and I'm going to have so much load and we have a mechanics basically. Our design equations so we can design it for the two resistor. Let's say the load we can calculate the stresses and then put it off material in the that provide the resistance that is needed. But other structural engineers really, we don't quantitatively try to assess the, and design for the corrosion, I mean corrosion, you can have the basically the specially with the still element that are embedded in a in a concrete. So, the concrete provides a protection for the steel enforcement. But you have a salt water and the chloride kind of seeps through because the concrete is porous material. So, the chloride itself really doesn't cause the corrosion but it.

[00:06:02] Atorod: Ingress, through the concrete and then destroys the film, the protection film that the concrete is providing for the steel enforcement, and it causes basically cracking initiation and then the corrosion starts. Once the corrosion is starts then you're building with the material that's is going to be taking more space and then causes the expansion of the basically inside the concrete and the cracking and unfortunately you.  It's very difficult to see it until the you see the cracks outside and that's probably it's a little bit too late. Now in the coastal area, we have two way. There's a the carbon induced basically corrosion.  And there's also the chloride induced, basically corrosion. And there are some tools that you can predict how long it takes, right.

[00:06:57] Atorod: But those tools that we have to predict, for example, it's called technical term, the error solution to the fixed second log, for example that we can use to predict how long does it take for the chloride to reach the steel level. But there are many assumptions that goes on in there, but the factor of safety could be 4. That's ridiculous. I mean, that means basically you are just crossing your finger and that. Hey, nothing bad is going to happen. Let's say in the case of bridge elements for example. We do a fantastic job to design something for the strength, but then after we design for the strength. And then we come back and then do some selected certain details and they would say, OK, no, we have designed it for the basically against the corrosion. But I think my mind, I think we have to be in a very quantitative manner we need to design for corrosion the same way as we do for the strength. 

[00:07:58] Atorod: One more point in my opinion, if you design, especially in the case of the bridge, buildings are a little bit different. In the case of the bridge, if you design let's say a bridge deck, against the corrosion, again which is service life, I call that service life. If you design first for service life.  And then check for strength. You're going to find out the strength is a bonus. You're going to. You're going to have so much strength that you won't need. So, what does that mean? I mean that that really points out something that I've been kind of preaching in in recent years. And that is we need to make a fundamental change in our approaches in design, especially with respect to the bridge.  Not every element of the bridge, but there are good number of the bridge elements that we need. First design for service life and then check for the strength.

[00:08:57] Atorod: That means, in my opinion, is a time to take your step toward development of the next generation of the AASTHO RFD. This is a very probably loaded statement that I'm making. OK, but if you think about that, and it really relates to the resiliency too.  There are very few examples that you can find that the bridge element the bridge have collapsed because extremely heavy. This humongous load that passed over it. It does happen in the in the rural area the steel trust bridge and but it's not. It's not the common, but what is common is the bridge, because of the corrosion. And where do we spend most of our time? We spend most of our time in design for strength. And we cross our fingers so that it has a service life, and that's what I've been in recent years. I've been preaching that really, it's time for us, I think to...

[00:10:00] Atorod: Just like the fact that in the 80s we switched from the.  The AASHTO bridges specifications, which was an older version.  For to development of the AASHTO LFRC, bridge design and specification. That was a major transition, I think now.  It's time for us to take a step to develop the next generation of the AASHTO bridge design and specification. One. that for most bridge elements. Tries to address the service life.  It doesn't matter in which order, but in a very quantitative manner, not just by selecting the details.  And you're going to find the, for example, the bridge deck. If I design a bridge deck for service life, trust me, you're going to have so much thickness in there.  That the strength is going to be just a number. the Hardy Cross actually in 1940s he made the statement, and I don't remember exactly which, which one of his books was that he says “strength is a number; other than that, doesn't mean anything.”   So.

[00:11:10] Brian: And yet we’ve hung our hats on strength. Right, all these years. So what you're saying is we should have a fundamental change in the way we're thinking about what makes a bridge good. What's the point? Right. Like, we kind of assume these bridges are going to stand forever. But obviously that is not the case. So how does one design for that service life and for ensuring that you don't have these issues with corrosion and other problems that you've seen pop up?

[00:11:43] Atorod: Well, there are minute things that for example, in the recent years, I think some advanced materials have also become available.  For example, ultra-high-performance concrete.  Ultra-high-performance concrete in my opinion, I think it's a future of not only the bridge engineering, but it's the future of the structural engineering, in my opinion. I think ultra-high-performance concrete has opened a in new horizon. And now it is allowing us to do things that we were not able to do. For example.  I work in an accelerated bridge construction area, ABC, right, and one of the most there are three different methods of they're trying to design or to constructed bridge using ABC method and the most popular one. OK, it said SPMT. It's a ladder on the slide and then it's a modular approach. The modular approach is the most used technique, ABC technique is a modular what the modular means is that you take a, let's say steel beam or a concrete beam, you take it...

[00:12:44] Atorod: With a concrete deck on top of it and that becomes an one module.  You get about four modules, you bring it to the side and you reduce the number of the construction days and then you attach them together, which is a joint. No. The common sense in the bridge engineer didn't says the less joint you have, the better off you are.  So here we have it. ABC which is.  Great idea because you reduce the number of the construction activity days on the site, the total construction time doesn't decrease. It's just an onsite construction, right. But then you have these joints now if you use the ultra-performance concrete to connect them together. You will have solid structures, so it is allowing us to that, not closure joints, for example. The other thing is that ultra-performance concrete, you know one of the reasons that in fact bridge industry is way ahead of the building industry and use of the ultra-performance concrete.  

[00:13:45] Atorod: I think it's going to get more popular. One of the reasons that last few years I've said looking at maybe six years ago, seven years ago, people were hesitant to use because of the price.  But now there are many universities, including our University Transportation Center, ABC UTC. We have developed a nonproprietary UTC. PCI has developed. A good friend of mine, Mehrdad was at the University of Nebraska, Lincoln, and with his team they have they have developed at this nonproprietary you UHPC. University of Michigan has developed it. New Mexico or has developed it, several other. So, there's nonproprietary UHPC is now becoming available and the price everybody agrees somewhere between $500 to $800 per cubic yard, whereas the commercial version. That's not there. All in order of 4-5 in place, it can cost you. I've seen number 10,000 dollar, $12,000.

[00:14:47] Atorod: The reason for that high prices because when you get the commercial version, you have to get the technicians, you have to get their mixers, you have to get this and that adds up. It's not just a matter what the not, it's not a brain surgery to make it concrete mix. Our graduate student makes the UHPC in the lab. So, everybody can do that. The contractors are much smarter than in the field and graduate. So, to make it longer story short, I think the UHPC I think it's a future and the one of the things that was blocking the use of it was the price of the price is going down because of the availability of all these nonproprietary UHPC now. So you wrap, it the if I may just add more to it. Why? Why UHPC can really help. Let's say for example, if I take a, we have one concept. Actually, that's called the UHPC shells. So, what we do?

[00:15:43] Atorod: We replaced the form work with the UHPC. Now you’re printing it.  You're printing the basically the form work with the UHPC right? Imagine you want to make it just a box for rectangular box. Very simple, right?  We have printed.  12 feel wide, 12 feet long.  14 by 14-inch box. Using a UHPC, using a 3D printer using the printer that we have developed ourselves, right? So now imagine you want to that box is a let's say cap bean I'm just giving example so you can print it right and it should be just an inch and half thickness the walls. You can take it to the field. You can put the steel cage in there and then you can fill it with the even lightweight concrete, right?  Now you have eliminated the time that it takes to build a form work on-site. You are eliminating the time to go back and remove the forms. You have made your structure resilient because what's inside is probably is going to be protected for life.

[00:16:48] Atorod:  The nothing penetrates through the UHPC the rapid chloride permeability numbers that we are looking with UHPC is an order of 50, 60 Coulombs. The other thing is that even that small thickness, that of the UHPC that use.  It allows you because it is so strong it's 5 times, 6 times and more stronger than the regular concrete. It allows the member size to get the smaller. Members get the smaller, I can put lightweight concrete inside.  Now the total weight of the structure gets smaller, the foundation size gets smaller. UHPC now is allowing us to make our structure resilient against extreme event. It allows us to develop the structures that are almost maintenance free.

[00:17:37] Atorod: And also, it makes the very fast construction. It's a form of ABC. The contractor cannot say I don't have experience. What do you mean experience, or you’ve got the element you just stacking on top of each other and it's not there's nothing. The contractors usually like to be for the prices because our perceived risk. So, this is a fantastic, great idea. I think its a future. Now some people have. I will say this one and some people have accused me of.  Being a more of a steel guy.  I look at the what is the best way to build this structure? I don't care if it's a steel, I don't care if it's a concrete, but I can tell you that over the last four years, 95% of my research has been on the UHPC because I truly believe in. That's the future of this structural engineering.

[00:18:28] Brian: Okay, let's pull back a little bit and talk about UHPC. Some of our listeners may not even be familiar with that term. So, can you just give us a general description of what ultra-high-performance concrete is and what makes it so revolutionary and effective?

[00:18:45] Atorod: Yeah.  Ultra-high-performance concrete. The mix is similar, in a sense, to regular concrete, but we don't have a coarse aggregate. It's very fine aggregate and it has a very low water cement ratio, very similar to high strength concrete that was back in the late 80s, early 90s. The major difference is that in the UHPC we used lots of steel fibers. And that's what actually adds to the cost. That the reason for the cost of the UHPC to be high is because of the fact that we are using steel fiber. So, you're using it more cement, usually cement type 1 user water cement ratio of something order of the point 2, point 22, you don't want to go higher than that. You use basically sand as or aggregate. It's a very compact material, that's why nothing goes through it.  And then you use lots of high range water reducers because you have a very low water cement ratio. So, to make it flowable to make it workable. That's why we use a higher range of water reducers. 

[00:19:52] Atorod: And then we use lots of steel fiber like 250 pound of steel in one cubic yard. So that's it. That's a quite a quite a bit. So, it's a 2% usually use a 2% by volume of the material is still fibers and that's a very small steel fibers, very high strength about 300-400 KSI steel fiber is very short and very small diameter.   And then the material, the UHPC. First of all, the strength is about could be anywhere between 18 and 30 KSI. So, and then, but the post cracking once the cracking forms, you can sustain that. Basically, the tensile strength. So, the tensile strength could be about the .8 KSI which is very good. So, it has a good tensile strength to it. So that's what really the UHPC is. And the good thing is that in the Europe they've been using this UHPC for number of years for upgrading, strengthening the deficient structures.

[00:20:52] Brian: When we look at specifications for materials, a lot of times these materials are tested based on conventional properties such as strength and as you mentioned just in the example you gave for strength, that strength is going to exceed most designs for typical concrete strength anyway. So, like you said, it's kind of just, it's just there, it's assumed it's going to be strong enough. So, are there some tests that we should be thinking about to determine the quality of the ultra-high-performance concrete rather than strength? 

[00:21:26] Atorod: There are the standard tests that you can use like rapid chloride permeability numbers, for example, to assess the durability of the of the material, freeze-thaw cycle. For example, there are a standard ASTM test. With respect to the UHPC, there's a one additional test at the Federal Highway Administration have suggested.  Ben Graybeal and his group has done a wonderful job at the FHWA: that's a direct tensile test basically. And so, there is a specification for that. Another thing with respect to the UHPC that has been kind of lacking is a specification.  Because the structural engineers like to have a like ACI code, AASHTO code - so that is working. So, the AASHTO is working. I think the draft is out. The draft of the design provisions for the UHPC. 

[00:22:23] Atorod: AASHTO has led. There's no standard, there's no ASTM become because that takes a long time. I believe probably that was one of the motives to go through the AASHTO. So, the AASHTO design guide for the UHPC should be out fairly soon. And in fact, if anybody is interested in that, if they go to our website ABC UTC.  Website.  At the FIU.  September 13, we had a four-hour webinar that's going to be archived soon.  Ben Graybeal actually gave you a presentation on the upcoming specifications for the design of the UHPC.  And if they're interested in the how do you produce nonproprietary UHPC. They can go to the same in-depth webinar that we had at the ABC UTC website. So that gives you all the information that really you need, how to produce it, how to test it and everything that you know you need to know from A-Z But the UHPC.

[00:23:27] Brian: Great. And we will have a link to that for our listeners on our website along with this podcast episode, we'll put some links that are relevant for you so that you can learn more about it now. We talked about design; we talked about the 3D printing process. Are there any other processes that can be used for fortifying existing structures that may be experiencing inundation with sea water or something that could lead to rapid corrosion?

[00:23:58] Atorod: I think the one of the best uses of the UHPC is retrofit and upgrade and be proactive.  Especially in case of the coastal areas. I mean, if you have a bridge that is being exposed to saltwater and so on, the best way is just to put a layer of UHPC around it.  So, we have developed it technology, right, right now actually to retrofit and upgrade concrete columns, timber piles, using UHPC.  The use of the UHPC for a bridge overlay has taken off right now.  Because you can take your top layer of the bridge deck, and then put a…expose some steel reinforcement or you can add some steel enforcement and then just cover it in the UHPC rather than the silica fume overly or whatever you have. And that will not the only add to the strength, but it will add to the resiliency and prevention of the corrosion. So, we have a tremendous amount of activities in that area right now and in trying to beef up, upgrade, retrofit existing structure using a UHPC.

[00:25:14] Brian: One technique that I heard about recently at a meeting was using it in the shot Crete application. That kind of surprised me, especially with the steel fibers. [Atorod: Yeah.] I would have expected there to be a lot of. Challenges related to just being able to have that pass through.  A shot Crete applicator and be able to be applied in a in a consistent way so that it remains in a homogeneous state as it flows through. Do you have any insight into how that application works and its effectiveness?

[00:25:49] Atorod:  Yeah, you read my mind: the shotcrete, actually, I think that's it. The one of the best ways trying to retrofit and upgrade, let's say existing let’s say columns you have.  Is a pneumatic basically “shotcrete” usually using pneumatic, not “shotcrete” because “shotcrete” is a copyrighted term or whatever it is.  When we started using a shotcrete, using the UHPC. We had lots of challenges. And like you said, one of the challenges was that we were using a basically we had a pump that we would put the UHPC and then you would pump the basically the UHPC that has a fibers and this had exactly the same mix that we use to cast for cast in place. But then the fibers would get clogged in and then we had lots of problems with it. And we finally after a year. They figured out what to do. Basically we use some admixtures.

[00:26:48] Atorod: VMA Viscosity modified agent basically trying to change the viscosity of the of the material without changing its property short term and long-term properties. OK and then the other thing that we that we learned was that we had to prime the line. So, we would put a basically grout prime the line and then once the let's say regular grout would come out of the nozzle then right behind it.  There was a basically UHPC and now we are able to shotcrete basically vertical surface or upside down or whatever you have. And I think we have taken the first step. I can't see in future should be able to use a shotcrete for the bridge deck overlay. Might imagine that. We are your long way from there, but I teach school.  Imagine you go in like a hose. You just spread the UHPC on top of it. It takes you a 10 hours. It's already set.  You've got a new bridge.  A fraction of the cost of the replacement. I see in the future may be moving to that, but we are not there yet.

[00:27:54] Brian: That would be a really interesting process. I imagine that would probably get the bridge to be put back into service pretty quickly too with a process like that. 

[00:28:05] Kim: So, I have a question. So, if you are putting the ultra-high-performance concrete over the bridge, because I'm not technical, so I'm just trying to like envision this. So that would basically your it's like a exoskeleton around the bridge supports and then.  So, anything inside of that is preserved at the same strength, and then it's adding strength on top of it. Is that what's happening in that scenario?

[00:28:29] Atorod: Actually, you’re asking a good question. OK, let's say for example you have a column right, a bridge column.  And you are seeing some sort of a corrosion activity going out. But what you have to do you have to with the sandblast or the water pressure, you need to remove some of the concrete. The European experience is that you don't need to remove all the contaminated concrete.  You need to remove but the one inch beyond the steel main steel reinforcement that there is. And then cast the UHPC around it. You have to be careful with the surface condition because the existing column is going to have a regular concrete aggregates. You have to have a good aggregate exposure. And you have to make sure that before you cast the UHPC against it you have to make sure that it's a dampened. So, there's a moisture in that interface, that surface. Because UHPC doesn't have that much water in it. Water cement ratio is .2 and if you if the surface that you are casting the UHPC against is not moist it's going to suck all that little water there is and they cause a cracking. So, to answer your question, with the sandblast or other techniques we can remove some of the concrete and depends on the how much corrosion do you have activities you can add some steel reinforcement in there if you want to and then...

[00:29:53] Atorod: The prepare the surface conditions, expose the aggregate, moist-condition the surface, and they cast the UHPC against this. Now when you do that, you don't need too much material.  In the case of the timber piles, it's different.  In the case of the timber piles, we concluded that you cannot rely on existing timber pile to carry any portion of the load. So, we said we're going to just, we're going to in case that tempered part with the UHPC and design it so that all the load is carried by the UHPC not the timber pile. There was a one major problem.  Timber. Depend on the moisture can expand and contract and so the in initial work that we did was this timer piles would kind of expand a little bit and then cause a tensile stress in the in the shell the UHPC shell that you were casting against the timber pile, because the cracking. 

[00:30:54] Atorod: We solved that problem by putting in a very thin layer of foam on the surface of the timber pile and then cast the UHPC against that, and that's solved the problem. You do need some reinforcement and all that. So, there is some preparation work that comes in. You don't just go and just spray or cast your UHPC against the existing you have to prepare the surface.

[00:31:17] Brian: I'm really glad you addressed that because that was one of the things I was wondering about is there's differences in thermal expansion. Because what you're doing is you're applying something that where you've tested and thought about that.  [Atorod: Yeah.] On something where they did not think about that. So, you could have some variability there, but yeah, that answers my question there. But I've got another tough one for you. You know, bridges aren't just a means of getting across the river or over, or some body of water, or gully or something like that. They often have cultural significance. Some of them have been designed with artistry, and they have, you know, social value beyond.  Transportation, right. So, when you've got an old bridge and it's probably happens in Europe and other parts of the world that are older than America where you've got these problems going on, it. Can this material be used and still preserve the other value of those structures?

[00:32:17] Atorod: Yeah, I mean, you're referring to historic bridge. So, the historic bridge, the appearance should not change. So UHPC is not going to solve all the problems. So, I have a strengthened for example that the historic bridge for example when I was at my previous institution, I saw any element that you put in the historic bridge that is meant to increase the capacity have to be hidden basically. So, you don't you don't change the appearance of it but the foundation part of it, yes.  So UHPC probably is not a good application there because it may change the appearance of the bridge and you don't want to do that in the case of the historic bridges. But the foundation part of it, yes you could do that.

[00:32:56] Brian: Now what one last thing I wanted to ask about is, you know, the traveling public can misunderstand things, or be concerned about things they don't need to be concerned about sometimes. And one thing that I could see coming up here is we're talking about putting little threads of steel throughout concrete which could be used on an overlay, and I could imagine somebody saying, well, what about my tires? You know, I'm worried about tire damage. Can you, can you say anything to address any potential concerns people might have about that issue?

[00:33:28] Atorod: Yeah, sure. I mean, first of all, this fiber is very, very small, OK and there are solutions the in the cases there has been several bridges, especially actually long span bridges that they have put a UHPC overlays and the contractors actually have gone back. And by grinding and making this, we're getting rid of steel reinforcement so that that is not an issue at all, because this is steel fibers is a very.  Tiny still fiber that some of it is sticking out what the contractors have found their way is trying to get rid of that and make it smooth. So even if somebody walk bare footed in there so they don't, they don't get basically injured.

[00:34:07] Brian: Sorry I said that was my last question but one other question I have for you. This will really be the last one. Other than what we've been talking about today. Are there any other applications or materials that you're particularly excited about in the future beyond what we've been discussing right now?

[00:34:23] Atorod: Yeah. I think if I look at the crystal ball.  That what holds in the future. I see several things. Automation I think is going to play major role in the coming years. It's not a science fiction anymore. I mean, different industry have moved into the automations and the construction industry has been fairly slow. But believe it or not, actually bridge industry is ahead of the building industry when it comes to the automation. Like a 3D printings and things like that. The other thing that I see with respect to the bridges structures that I see major changes that are being incorporated. I think technology is advanced. Technologies are finding their way into bridge engineering like artificial intelligence. For example. So the decisions that we were making. Based on just the one’s experience, no you can't couple that with the with the artificial intelligence in order to make your better decisions. 

[00:35:28] Atorod: The other changes that I see that for example, that you're paying more attention now in making all the decisions that we are making is.  Now, we are considering it's going to be more and more the safety, the mobility.  The resiliency.  The social equity, for example.  These are the factors that really goes engineering. Bridge engineering is just like you said, I mean, it's not just building a really bridge. I mean you, you shut down. For example, if one. One bridge, I mean that get that can have a really.  That's significant impact on the on the businesses. I'll give you one example. Actually, I come to the TRB of course, every year. I believe it was in 2019...  

[00:36:20] Atorod: There is a restaurant that you really like in the Washington DC area. I went 2018.  And I went 2019. They were replacing one bridge and it was in a street that they were lots of restaurant and there was one restaurant I love, so anytime I come to Washington, DC I go there just because of the food and.  And every time I went, I didn't. There was a big sign, too, that the I don't know what agencies building the bridge over here. And this poor businesses on the side they were suffering basically from that because the construction was going on.  And I talked to actually the one of the businesses I said, do you guys know that you can probably replace this bridge over the weekends and ohh yeah, I said yes, there's something called accelerated bridge construction. So actually. These are the not the decisions that we are we are making. I think it's going to change the way there's going to be more tools available for the decision makers. OK, not just the structural engineers to make decision that accounts for the resiliency, climate change, social equity impact on the impact on the businesses and so on.

[00:37:31] Atorod: So, you know, you look at the 1940s.  I think during the time period that we build the Golden Gate and the Manhattan Bridge and all that they were, I mean you look at it, the amount of the different innovative technology that was incorporated was tremendous. But then you see a gap, a little bit, things are steady, right. But now I can see that with this artificial intelligence, monitoring sensing and blockchain.  Advanced Materials automation, 3D printing. I see exponentially. We are going to, you know, our bridge industry is going to really move forward is much faster way because of all these advanced technologies and the credit to the US DOT. The US DOT is putting it lots of emphasis now on advanced technologies such as the automations, 3D printing and so on. The bridge engineering is going to move...I can see in the in the next 10 years...It's going to look. Nothing like what we have right now.

[00:38:59] Brian: Yeah, that's exciting. And I I think that like you mentioned that a good example of what is in it for us, you know, not just as the traveling public, but just the public in general. You know, people who have restaurants, people who just want to have a better life. So Atorod, I really appreciate your time today you you've covered so much of this in such a great way and you've given us a lot to think about. I'm excited to see what comes next and if somebody has any questions or follow up where they where can they get in touch with you or get more information about what you've been working on?

[00:39:12] Atorod: My e-mail address is very simple, just contact me through the e-mail address AAZIZINA@fiu.edu.  So just send me an e-mail, I will be more than happy to talk with anyone that wants more information on what we do so. We'll be happy to do that.

[00:39:34] Brian: Alright, sounds great. Thank you very much.

[00:39:37] Atorod: You bet. Thanks for the opportunity. 

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