 Welcome to this episode of the Structural Engineering Channel podcast. A podcast focused on helping structural engineering professionals stay up-to-date on technical trends in the field and also help them to succeed in their careers and lives. I'm your co-host Alexis Clark. I work in Hilti's North American headquarters as the product manager of our chemical anchoring portfolio in the U.S. and Canada. I'm a licensed professional engineer in Texas and I graduated with a degree in civil engineering from UT Austin. I'm your co-host Matt Bacartal. I'm a licensed engineer at DCI Engineers, practicing on structural projects in California with an undergraduate degree from Cal Poly Pomona and a master's degree in structural engineering from UC San Diego. Before we introduce our guests, we'd like to let you know that the Engineering Management Institute recently launched another podcast, the Geotechnical Engineering Podcast, which can be found at geotechnicalengineeringpodcast.com. This podcast will be focused on helping geotechnical engineers stay up-to-date with the latest technical trends in the field. The host is award-winning geotechnical leader Jared Green, a licensed professional engineer who's been practicing as a geotechnical engineer for 20 years. You can find all of the episodes on Apple Podcasts or wherever you listen to your podcast. And you can request guest topics and ideas at geotechnicalengineeringpodcast.com. In this episode, we talk with Jason Lloyd, a bridge steel specialist at NSBA. We found Jason through an article he wrote in the AISC Magazine Modern Steel Construction on redundancy and steel. And in the episode, we will be talking to him about everything from redundancy and steel, steel bridges, failure critical members, and everything in between. He really gives us a deep dive into his entire world in both research and in practicality. Now let's jump into our conversation with Jason. Jason, welcome to the structural engineering channel podcast. Thank you. It's a pleasure to be here with you. Pleasure to have you. We are really excited to have you with us today. Before we dive into all of the fantastic questions we have for you, can you tell us a little bit more about what you do on a daily basis, kind of what your routine looks like at NSBA? Yeah, absolutely. So NSBA, of course, is the National Steel Bridge Alliance. We're a non-for-profit that's headquartered in Chicago. And we have a number of staff that work remotely, you know, from their homes primarily, and then we travel around, you know, different parts of the United States visiting departments of transportation. You know, different, those are the major owners and clients, I suppose, but, you know, they've got different clients that will perform design work for them. So we'll interface with those clients, with those designers and consultants, and provide technical resources, you know, education outreach, continuing education opportunities. We'll develop different evaluation and design tools that help make a designer's life a little bit easier, maybe save them some time, help them in their design processes. And so my day-to-day really is helping develop some of those tools, reaching out to these people, interfacing, providing solutions where there might be questions and those types of things. Cool. Jason, I know you also spent some time in the, from your bio in the Navy Civil Engineering Corps. Could you go into a little bit more about that, maybe what you benefited from it or what it's taught you? Because I just know I haven't, I spoke into a few engineers that have been in the Army or, and they've learned a lot of it, so I'm curious about what that kind of taught you. Yeah, absolutely. Yeah, I guess it's probably a little bit unique. I suppose there aren't too many people that go through the Civil Engineering Corps. It is a section within the U.S. Navy, also known as the CDs. So I don't know if you've heard of the CDs or not. They have a pretty rich and very interesting history. In fact, they started back in World War II. You know, in response to a need for the technical tradesmen like, you know, the carpenters, the electricians, the mechanics, those types of folks who were necessary for the fighting forces that were moving the front forward. And, you know, they were civilians at the time couldn't defend themselves by international law. And so what grew from that was a group of military personnel that was trained to defend themselves as well as be craftsmen craftsmen and tradesmen like, like what I've mentioned so that's hence was born the CDs. And yeah, my time in the Civil Engineering Corps was fantastic. I love the opportunity. I spent about six years in the Navy, all together. I started in a program that's called the collegiate program which is kind of like what most people are familiar with most people have heard of the ROTC program during, you know, you do during your bachelor's degree. This is kind of similar but different in the sense that I enlisted while I was in my bachelor's. You know, I had, you know, you know, I had to keep my grades up had to stay physically fit those types of things the military requires. And then once I graduated I went into officer candidate school down in Pensacola, Florida. And that's where the it's kind of like a boot camp for officers, you might think of it. Okay. So it's, it's tough and it's very stressful. And it's an experience I look back with her back on and think, you know, I'm glad I made it through there but I never want to go back again. So that really, that really pushed me outside a comfort zone for sure and that was, that's really my big takeaway from the Navy is it opportunity and experience after experience pushed me, you know, in directions that I probably would not have chosen for any other path along my career. You know, took me to places throughout the world that I would not have seen otherwise. And so it helped open my eyes to really how big this world is even though sometimes it seems small, and how complex some of the things are that we face as a global community. And so, you know, that was a fantastic experience for me. It, it also gave me an opportunity I think to, to mature quickly in my career path. What I mean by that is, you know, coming out of school, going into the CEC. So almost right out of training they put you into a owners representative construction management role, where you're overseeing millions of dollars in construction contracts, you know, interacting or interfacing with the contractors, the commanding officers who in this sense really are your clients, you might think. And so it pushed very, very quickly into a track that puts you in a role that any, and I think in any other sector of our industry probably would take years and years to get to. And so it, you know, really, really pushed me to mature and to grow up fast, and to, to learn the processes of our industry very quickly. So those are probably some of my biggest takeaways from being in the CEC is a fantastic experience. Thanks. That's, that's great. You know, I never really thought about that contractor side too, because, yeah, you know, if you're a typical engineer, you just go to school and then you're thrust into the industry. It's a shell shock when you see kind of when you go into, I don't know, a heated owner meeting, OAC meeting. So it's like, you get used to that environment. So yeah, that's really interesting to see that you get to put into that environment and and see what it's really about and kind of knowing how to handle yourself and how to, you know, adapt to other people's personalities. That's, that's really good though is pushing yourself to like once you once one challenge after the other then it kind of builds up your confidence like, I've been through worse so I can do this next challenge. That's great. Yeah, exactly. I would also imagine that I mean of course anyone who's gone through an engineering school, even undergraduate degree understands that there's a certain level of discipline that's required to get through there but there's an entirely different category of discipline from any kind of armed forces. I also understand one of my girlfriends from college she actually was a naval officer and having having heard some of her learnings from being in in the forces is kind of learning to almost play politics in a more in a more way because there is a hierarchy of a chain of command and you have to be much more respectful of who you're speaking with there's there's much more rigid expectations of how you handle your your owner and your clients and the people that you also still have to report to and so I imagine that coming out of that experience you probably had a better way of navigating those differences and differences of opinion and perspective and priority and being able to to mitigate those conflicts. Yeah, absolutely. Yeah, I mean I was raised to respect elders to you know that was you know very traditionally I think you might say raised and so that came naturally for me but like you're saying there's certainly within the military. There's a tradition of respect and hierarchy of command and a very strict formality that's put on top of that right and so yeah absolutely come away from that was was it was eye opening and also I think very good for my for my growth in my career as well. And I think you just put your finger at maybe the word I was almost looking for was the formality of having to work in that kind of interaction and I think that's something especially for young college students when they haven't had that kind of interaction whether they you know didn't have those opportunities as an intern when they were in college or if they just didn't have the opportunity to kind of flex this professional muscles. That formality probably gave you a huge leg up in the long run because you did have to to navigate be able to present yourself in a very different way from the typical undergraduate engineering student who's just entering the workforce for the first time. Yeah, for sure, especially nowadays right where we're all in the corona pandemic and we're working in our sweats from home. Yeah, it's it's. Oh yeah. I definitely understand that I think we're all wearing we don't but none of us are wearing a color shirt right now right. I got I got a polo. Women just don't wear polo. Women just don't wear polo is I'm not gonna I'm not playing that game, but I appreciate you dealing with my, you know, my slutty t shirt. Perfect. So you spent several years after after your time in the core as a research engineer and as a graduate student for Purdue University. And from what I understand you did some full scale experimental research. This is kind of way at my alley and I'm really into testing I as a man working for a manufacturer this is like my jam I love this kind of stuff so I have a ton of questions and I'm just going to throw them all out you and then you can just answer whatever order you want. So I am looking for you know I'm looking for you to kind of paint our listeners a picture of of what this looks like what full scale testing looks like I mean this has happened in a facility this has happened on site. Is it a mix of both depend on who you have partnerships with what is the scale of full scale are you are you mean it says 50 feet is 100 feet you know what what kind of site dimensions are we working with here. How is this type of work funded. What is it that you can learn from a full scale tests that you can't from others is there a specific objective that you have going in I want the full rundown. I can tell you definitely are into this right that's exciting topic for you. Good. Great list of questions. I'll see if I can tackle all of them and if I miss something just remind me. I will thank you. Yeah so there's there's I think there's a little bit of vagueness I'll say in the definitions between full scale large scale and small scale experimental research. And so I use those terms a little bit loosely but to answer your question full scale really is anything that in the in the in the test itself represents the scale of what it is in the actual world. And so maybe you've seen videos or maybe even in person you've seen excuse me you've seen structures like 368 story buildings that are built primarily outdoors on top of a big shake table or something like that. So these are structures that are large enough at a scale that they would be built one to one in the real world that you could actually live inside these structures and they test them at that scale for certain reasons. A lot of times. And many many I'll say many types of research you are able to scale the effects of force load displacement strain you can scale those things all down and make those tests much more affordable so that one you can afford to do the research but also so you can increase the sample of their specimens right if the specimens are incredibly expensive and you destroy them every time you run a test and those tests that that experiment the program becomes extremely expensive to do and maybe not even feasible. Alright so that's what the scaling effect allows us to do as researchers. So full scale really is anything that you would see in the real world so in the you know coming back to bridges which is the world I live in so to speak. A full scale specimen would be something that would be of a scale one to one that you might see in a bridge. So, you know my days at Purdue University we did mostly large I'll say large scale but some full scale. Again there's maybe some blurred lines between what those two things are large scale in my opinion is something that is maybe not quite one to one but it's still large so for instance we were performing some fracture tests on axial specimens. And these specimens you know they were you know two feet wide and 16 feet long so they're large specimens it's not something you fit on your countertop at home. But it's also not necessarily the same scale of a specimen or a member I should say that would go into an actual bridge, but it's large enough that it captures the same behavior, maybe locally for some kind of a test parameter that you're trying to observe right. So that's that's kind of the nuance I think between all large and small scale. So, if large and full scale are more expensive and more time consuming to do. Why would anybody ever do them right that's kind of the question what do you get out of full scale testing that you don't get out of small scale and if it does cost more and take longer than you know why do it. Which is a really great question actually. So there are certain aspects of our engineered world that you cannot scale. And one of those is fatigue and fracture. So there are conditions that will affect the behavior of us of a fatigue and or fracture specimen that can't be scaled down so maybe you've heard of the truism that a chain is only as strong as its weakest link. Right. And so, probabilistically speaking as that chain becomes longer you have a higher probability that there's a link within that length of chain that has some kind of a flaw. And when that and that flawed link is going to basically limit the strength capacity of that entire chain right so more chain links higher probability of a distribution of a flaw somewhere. That also applies to fatigue so the fatigue resistance of a specimen has a random distribution of flaws that are introduced either through material processes or assembly processes fabrication processes in the welding etc. And so this random distribution of flaws can't be controlled necessarily can be mitigated a lot and we've you know we've done a lot of things in our industry to improve that. But they still there's still this random distribution and so if you take a fatigue specimen and you scale it down effectively you're reducing the length of that chain. If we continue our analogy right so we're reducing the probability that there's a flaw somewhere that would that would reduce the fatigue resistance of that specimen. And so what you have in a scale fatigue specimen is kind of an artificial increase in fatigue resistance because of that that kind of making sense in that analogy. Yeah. Yeah, so when it comes to fatigue and fracture we have to work in a world of full and or large scale specimens where we have, we're not affecting that random distribution of, you know, a possible flaws in the in the processes are in the materials themselves constraints as well you know contribute to that. So these things all have to be done in a world of large and full scale specimens. I think you asked about the funding. So these, this type of research is funded from a number of different sources. Sometimes it's federal funding will come through programs like the NCH RP which is the National Cooperative Highway Research Program. Oftentimes states will have their own research funding. Sometimes a state will have some kind of a research project that they're interested in and they'll fund it themselves, or if there are multiple states that have a vested or a common interest in that particular project and they'll pull their money and what's called a pooled fund project. And then there's also proprietary funded projects and we did a few of those that Purdue you know you have a manufacturer, for example who's got some kind of a product or a system that they want to test and they'll hire someone like a Purdue University to conduct that research on their behalf and so it's privately funded as well so lots and lots of different ways to fund those types of projects. Gotcha. Do you have anything to do with with sourcing funding. Are you ever involved in in those in evolving those partnerships. Um, at the time when I was a research engineer at Purdue I did not, you know, we would write proposals all the time when, and we would, you know, we would talk to states and see if they'd be interested in this project or the other project you know those types of things and we were soliciting funds and trying to gather interest or if we heard of a project that was being funded then we would go after that funding and you know submit proposals like most people would do. Now that I'm with the NSBA where we do have a little bit of a research arm as well and what can you know it's in our in our mission. Then, you know, we are, we're extending now I'm kind of on the flip side of it where we're extending funding to the researchers now who are out there conducting different types of research for buildings and or bridges. And so in that sense kind of but I think really the answer to your question probably is no. Yeah, but but I've kind of seen both sides of that and it's been great experience see both sides. As enough during your time during research what was, let's say one example of a finding that really stood out to you that you know you can share with our listeners like, like what was like one of the main things that you just really found really interesting and you weren't expecting or something that just stood out to you in terms of your research findings. That's a great question. I think if I if there was like one big takeaway for me coming into, you know, research fairly young in my career. One of the takeaways for me came from after years and years of performing field tests so let me back up just a little bit one of the things that we used to do we so we did kind of the more traditional laboratory based research that, you know, that's been interesting about in this conversation but we also had within our program where we would go out and field test existing structures for DOTs maybe they had a problem or they were curious about something, or maybe a structure had some kind of a detail or a parameter that would pertinent to research that we were also doing in the laboratory either way we were, we would go out in the field instrument bridges and test them. So I got to see firsthand. I got to interview right the bridges themselves I got to put the sensors on the bridges and see how they're feeling so to speak, you know, gather data on the effects that the live load is having in those structures that the temperatures having on those structures as they expand and those types of things. And I think one of the biggest takeaways I get I got from from those days of field testing was that there's an incredible reserve capacity that tends to exist in our structures right when we use these empirical calculations to to compute what the capacity of a beam is a lot of times you know, you know for not using finite element if we're in the empirical world we're using distribution factors we're assuming that is being kind of just floats in space, and we apply these loads to it and these boundary conditions to it, and we predict its capacity, but then we go out in the world and we put that beam into place. And we connect a deck to it and we connect crossframes to it and floor beams and it becomes part of a system, and all of these interconnected components of that system weren't part of the analysis or the design, right. You know the original design so when live loads start to drive drive across the bridge. The distribution isn't really in reality what we assume it is in the design process. And so there's a lot of reserve capacity and you know that it might be said that the sum of all this system, the sum of all is the capacity of that system is greater than the sum of all this parts I'm trying to say. We've heard that synergistic that term before that really happens on the bridge and so I came away realizing that there's quite a bit of reserve capacity in our structures. And it was quite impressive actually just to seeing how effective how efficient the structures are. That's great. Fantastic and that's such a perfect segue. Sorry, Matt, did you want to ask something. Yeah, I had one. Yeah, I just had one tidbit on that just because I you know I spent some time at UC San Diego for my master's and over there they have full scale testing and that was really cool. And the professors would share their findings and they were mostly buildings I'm a building engineer and they were doing mostly buildings but also bridges to. But yeah, it was really interesting to see what their research findings were, you know, comparing the stuff that we design and code like per code but then when they actually do the research. They do find all these things it reminds me of, let's say for a wood shear wall building we're only taking to account the shear walls, the structural wood shear walls but in reality there's so many non bearing walls that contribute to the stiffness of the structure and all these things that don't really get taken into account to with our codes, which is good for some for most of the buildings out there they're simple but it really is interesting to see once you actually get into the full scale world large scale world, what they find out in full scale testing that which is cool because now we have some it kind of led to in the building design performance space design finite element nonlinear. It kind of gets into that realm which is really makes our designs more a lot more efficient. And it's, you know, it's because of that type of research that kind of opens up that field and what those benefits are from the research that you know universities are doing so that's that's what I find really cool and it's cool to see that you kind of had those points to. Yeah, yeah, exactly. That was very similar to my experience it sounds like. Awesome. What a great segue. So, I have a little bit of I actually several questions but I'll keep this one as simple as possible given the fact that you, you took the firestorm of questions about earlier so well. So, since, since you've left Purdue, I know that you have been working with NSBA and you've written several articles based on your almost full decade worth of research by not only yourself but with some other colleagues as well at Purdue. There is a specific article called revisiting redundancy that was published in modern still construction magazine. And in that article you talked about the historical considerations of redundancy and still bridges. Talk to us a little bit about your opinion on this and why you think engineers should consider other modes of redundancy and still bridge. Yeah, sure. Yeah, the motivation for me to write that article really was to challenge the status quo. And so my intent was to just get engineers who are in a mode of thinking to start thinking maybe just a little bit differently. Okay, so let me let me explain what I mean by that but first of all, I do want to give credit to my colleagues you mentioned my colleagues I've worked with some of the, the most impressive in intelligent engineers at Purdue University of my entire career they're very, very impressive. And I learned a lot from them so I want to give them credit Dr. Bonacera Martin, who now is working for Michael Baker, Dr. Matthew Hebden, who's now an assistant professor at Virginia Tech. Dr. Jim Corkmaz who is a post doctoral research engineer at Purdue University, and then of course, kind of the leader of the gang, and my mentor and good friend, Professor Robert Connor at Purdue. So all of us contributed to the research and many of the conclusions and things that I alluded to, and explicitly explained in that three part series article and some of those were my co authors as well that I mentioned so you've seen that I'm sure. So, yeah, so staff, you know trying to challenge the status quo where are we coming from the historical context for redundancy and still bridges is that long before we ever thought about fatigue and fracture and the design of our steel bridges. So designing these structures, producing the materials, you know, we were riveting originally then we started welding and then bolting. And along that process we were creating some details that we don't do anymore, right we've learned that they weren't fantastic necessarily in terms of fatigue and fracture and on occasion there was a failure. One of the most well known is the 1967 collapse of the Point Pleasant Bridge. It truly was a fracture critical member. I think arguably probably the probably the only true fracture critical collapse in the history of the United States. So there might be someone who will disagree with me but I'll argue that point. So that happened 1967 there was a knee jerk reaction and, and, and rightly so by the industry say hey well we need to take a step back and think about what we're doing these bridges. Maybe we should start inspecting them on a regular interval. And so some things spun up and came into play like the, you know the National Bridge Inventory years later we started inspecting bridges on a routine basis. Eventually we, we actually didn't define a fracture critical member until about 10 years later. You know 1978 is when the fracture control plan came into into play within the bridge industry and we defined a fracture critical member. And so, at that point we put ourselves in a box where we didn't have the, we might have had maybe some intuition, for example that a built up member has internal redundancy that. Within its own members cross section there might be multiple load paths, right. But we, although we had that intuition we didn't have any data we didn't have any well defined engineering processes or equations, we like our equations to really quantify what the redundancy of those members might be or even bigger what the redundancy of a system itself might be right the interplay of multiple components all tied together. And so we put ourselves in a box decades ago where the only mode of redundancy that we could rely on or that we really trust ourselves to rely on was multiple load paths. So instead of having two greater bridges we started building greater bridges with four, five, six, eight girders. Because we knew at that point that we had redundancy if one of those girders for whatever reason were to fail, like what that I bar did in the point pleasant bridge. We felt pretty confident that those loads can redistributed around to the other girders that are still intact, and the bridge would avoid collapse. Okay, so we're the effort was to protect the traveling public of course and keep people safe. But over those few decades where we kind of we put ourselves in that box so to speak in terms of redundancy. We've come a long, long way in terms of the quality of the materials that we're producing. So the steel quality today is much better than it used to be decades ago. We've improved in the toughness of our steels which that that that quality of steel that resists fracture in the presence of a notch. Our welding processes have improved tremendously our quality assurance and inspection processes have improved tremendously, you know in the fab in the fab shop as well as in the field. And so all of these things are working really really well together and we're producing bridges that are of a higher level of reliability than we ever have before and in fact, if you look back through the past 40 years since the fracture control plan was implemented. There hasn't been a single fracture fracture critical member that has failed. And so anecdotally that's telling us that we're doing some things right right this these improvements in material and welding processes the construction processes these things are working for us really well. And so on top of all those improvements that have come along as this last decade of research that you mentioned at Purdue University where we looked explicitly at. Okay, how can we take a system or a member that traditionally is considered fracture critical because it lacks load path redundancy and quantitatively evaluate for redundancy whether it's at the system level or at the member level. Okay, so that's really what we started looking at. My colleague, Dr. Bonacera looked at the system level effects, as well as Jim Cork Moss and he's been doing some fantastic work lately in twin tub structures. And then Matt Hebden and myself focused on the member level redundancy. So what came from those many years of research are a couple of ash to guide specifications that give engineers the ability to now say okay I have a process and some guidance that I can follow. That's that that either supports that intuition I have as an engineer that there is some redundancy in the system or in this member that I can take advantage or that I can design specifically for right. And that allows them to take now take advantage of different types of design so now we can take ourselves out of that box we put ourselves in decades ago that is only low path redundancy and that's the only way to have a redundant structure. And we have some engineering and some data to back up different ways of approaching redundancy without sacrificing reliability safety, any of those things in our structures. I think a little more creatively. Sometimes, you know, there might be a design where it's more economical more efficient to do a two girder, you know, or, or let me give you a really obvious example, perhaps is nowadays we build on occasion will build straddle that still straddle that's. And so this is a transverse member that goes transverse to the flow of traffic, and it goes from one support to the other, it might go across oftentimes they will cross four or five lanes of highway traffic. Traditionally, these are built from steel built up boxes they're welded together and they have to be defined as fracture critical and the requirement then on the owner is to inspect these at arms length, every two years at a minimum. But you can imagine not only the expense but also the danger you put those inspectors as well as, you know, traffic, because when you start changing traffic patterns you increase, you know, the probability of accidents and those types of things. And so we're putting them out at risk to inspect these these these components these these elements I guess you'd say because we have this idea I guess that it's fracture critical well what if we were to take that same straddle bit and build and design specifically for internal redundancy. And instead of making it a built up welded box let's bolt on the bottom flanges to connection angles. And so if in the unlikely event one of those happens to fracture that fracture is arrested and that member is able to continue to carry service loads. And so now what we can do is we can remove that requirement the arms length inspection requirement for fracture critical member and be a little more rational about how we how we inspect that member without sacrificing any reliability or safety for the traveling public. You know in terms of the low carrying capacity of that member. And really gives a huge advantage for the owner as well in terms of not only the safety for their inspectors but also the cost to inspect those types of members. That is really interesting and I always think that from from a cost standpoint we're always thinking about the cost it takes to fabricate or you know what the actual cost of the built project is but we don't often think about the maintenance. And of course that should be on the but it's something that we as engineers can show our expertise and our business leadership in is explaining maintenance cost later on the road so I think it's fantastic you guys obviously work that into one of the reasons that this is included in NASHTO but I think what's something else that I'm seeing that's increasingly more difficult for it for any facet of structural engineering is that the talent pipeline that specifically going into the inspection community is so restrained right now and we are expecting what is like a third of the entire inspection certified inspectors that are that are in the industry right now are supposed to be retired within the next five to 10 years. And we're going to have a huge drain on those resources so I think from a pernell or personnel capacity as well so I was thinking per do and personnel from a personnel capacity. The fees associated with inspectors is probably going to increase as we have fewer and fewer that are readily available and trained enough to be able to do these kind of inspections so I think it's really timely and relevant that you guys did such fantastic work to help us have different options in these situations and be able to provide more feasible options for owners in the long run. Yeah that's a really good point actually and that reminds me too that we did some research at Purdue and this is a one of a kind project it's not been done before or since but looking at the probability of detection for typical steel bridge details so under the guidance of Professor Connor we set up a test a test at the Esperite Center it's called Steel Bridge Research Inspection and Training and Engineering Center. And in that we had a random distribution of defects that we know exactly where they where they were and how big they were etc and then we would put trained bridge inspectors through this to see how likely they were to find those different defects. And one of the things we found is that we're expecting a lot of our bridge inspectors to go out there and find very small defects in what are very large structures that are complex with multiple components and lots of things going on. And so it's interesting that you make that point that not only are we expecting a lot of our inspectors but now that that personnel, a labor force might be reducing. You know even more will be required of them right which really brings to the forefront our effort in the last decade under under Professor Connor is integrating the fracture control plan. And what I mean by that is you know we've made all these advancements in materials we've made advancements in fabrication and in shop inspection. But we haven't linked to those things or integrate those things with the way we inspect and manage those structures in service. So give me give me an example. I could have on the same interstate, maybe a mile apart maybe right next to each other, a bridge that's 100 years old, and I could build a brand new bridge that opens last week. When it comes to inspection by law, as an owner I would be required to inspect both of those structures on the same frequency, right every two years. But that really doesn't make sense because once 100 years old it's not made with the same quality materials and processes. And so it might need maybe more frequent inspection, while the new structure might need less frequent inspection. Right. And so integrating the way we design and build those structures with the way we manage and inspect them is what we're calling integrating that fresh control plan. And that's really at the root of what we're doing with a lot of this research with redundancy is let's get away from calling everything by default fracture critical if it's non load path redundant. And let's look at what is the real redundancy that we can take advantage of maintaining reliable structures and then developing an inspection program is based on that reliability. Gotcha. So to summarize and let me know if I'm getting this right. So from all the research that you've been doing and from all the advances in construction. Basically, a lot of our bridges are stronger than basically the quality of the bridges are stronger so that means, you know we don't need to be as critical of them we don't need to inspect them as much. Or maybe we can get more creative with our designs because we know if they have some built in redundancy already, then we can pretty much it allows allows the engineer to become a little bit more creative in their designs or have more capacity in their members that am I getting that correct. I think that's a fair synopsis. Yeah. Yeah. So it's it's let's step outside that box. Be engineers. Let's be creative. We have a way to to quantitatively evaluate for redundancy now. So let's use that to be creative to use economy in our designs. And also to integrate that with how we manage them over their entire service life. Yeah. And I just wanted to bring up article number two. I remember you mentioned there was the was it the load carrying potential for for post failure load carrying potential. I think you go into first engineer needs to figure out if their their their bridge design is you know applicable for this. There was this guide that you mentioned on how engineers can basically use finite element analysis to classify it as a redundant structure. Can you kind of go into that a little more just so I want to I want to show the engineers that you know there's a resource out there that they can find but you kind of go into a little bit more about that. Yeah, absolutely. So yeah the second article is co-authored with my former colleague. Frank Bonacera. Probably one of the most talented engineers I've ever met, particularly in terms of finite element analysis he's he's he's quite credible. But he led that research as a graduate student that developed what is now a new ash to guide specification. It's not under an HRP project so report 883 if anybody wants to look up the actual research itself. But that developed into a guide specification which is the ash to guide specification for identification of fracture critical members and system redundant members. You can purchase that off of the ash to website now it's it's available. What this does is it standardizes the way that you can use refined analysis finite element analysis to evaluate for redundancy so prior to to Frank's work. There really was it was a bit of a while while West maybe if I can use that that reference. You know, we could we could evaluate systems for for redundancy using finite element, but there was no standard practice for that. And so it bears the question, you know, what loads should we use what's an acceptable performance criteria in that failed condition. And if it and perhaps maybe there's a performance criteria that's too strict. Right. And so, maybe we do want a little bit of a sag in the bridge when that component breaks so that somebody eventually finds it and we can fix it. So those are some big questions that hadn't been answered. And, and so Frank's work really helped answer all those questions. And so they developed some new load cases that are called redundancy one and redundancy to that is based all in the reliability world just how the ash to load cases are used in designing new bridges he developed these specifically for the redundancy cases and helped establish what the different conditions I'll say is in your fine element model need to have in order to have sufficient refinement to really capture the behavior, you know, from shear stud behavior to concrete crushing, you know, to the, to the behavior of the steel components themselves all that combined acting as a system so he took the industry from what you know, he didn't necessarily provide the industry something it couldn't already do but he standardized a good way to do it, provided a load model that had some performance criteria that could use to make those judgments on as to whether or not this the system really is redundant or not. Gotcha. And for me, it seems like the goal for the redundant systems is just taking for example I think I read in that article where, you know, one of the members fractured in a bridge, and like a tugboat went under it and saw the fracture but the bridge was still, you know, carrying all the loads from the typical loads that it has and I think that's, that's the goal right in terms of, hey, if something breaks, it's still going to function properly maybe not to the fullest extent that it could but, you know, the whole thing's not going to collapse just because something fractures it has that built in redundancy. And I think that's what we're trying to do with with these types of redundant structures right. Yeah, exactly. And those are bridges that weren't actually designed specifically to have system redundancy, they just inherently have that because of the conservatism that we used in designing and building them. Now imagine if we can take engineering principles and the advancements that we've made in mathematics and in software, our ability to analyze and evaluate these systems and explicitly designed for those cases. Now it gives me a lot more confidence that new structures are especially going to be redundant. And one one more thing to add is this is a this is a very conservative process that we're doing it needs to people. I can see how it might come across as an unconcernative practice. But the reality is is that risk is has two components risk is one part likelihood and one part consequence. And so in this evaluation we are conservatively completely ignoring likelihood. Like I mentioned in the last 40 years that we haven't had a single fracture critical member that has actually fractured. That makes likelihood extremely low that any new fracture critical members would fracture as well right so that likelihood is incredibly low, which makes our risk low. So in these analyses what we're doing is we're assuming that something does break. So we're removing likelihood from the risk and conservatively saying, Okay, something has broken. And now we're going to evaluate for consequence. And so that's what these ash to guide specifications do is they evaluate for the consequence what is the consequence of a non low path redundant member fracturing. And if it does fracture or when it does fracture I should say what are the consequences is it going to remain stable is it going to be able to redistribute loads and carry service loads like like what you talked about in that case right. So we have decades of anecdotal evidence, actual fracture critical members that have fractured, and the bridge continue to carry service loads until either, you know, a tugboat captain, or painters or birdwatchers, you know, all these, these are all real cases by the way. You know, these are people who have looked up and said, Oh, there's a, there's a giant crack that doesn't look right. While trucks and cars are driving across the bridge. Yeah, exactly. So, so we have a lot of anecdotal support. But now we've got a very engineering and research based process that we can do that explicitly in our new structures and we can also look back at existing structures and see if they, if they meet, you know, they make the cut as well. Thanks for sharing that Jason, I know we're going to provide all the links to that in the descriptions below. So if you guys want to look at those articles or, or find some of those links to those guides will provide them. I had one last question for you Jason on my part. Trying to get into more of the career aspects, you've had a very interesting career, different industries, because you go over maybe some of the lessons learned or some of the best advice you can give or to our audience, particularly new engineers or even engineers, you know, that are going through their career right now. Yeah, absolutely. Yeah, I think this whole process, you know, setting up this podcast to be interviewed by you has really caused me to reflect a little bit on my career, you know, to take a step back and look at where I've been, how I got to those places and and, and how, and how I've been successful. I think it goes with you've probably heard the adage that big doors swing on small hinges. I think that really could define my career very, very small points in time, where I've made a decision that if time might have seemed insignificant, have led to really big opportunities either because they led me to people who could provide those opportunities or organizations that can provide those opportunities, or because it just in that moment. I believed in myself enough, or I was curious enough to follow an instinct or an interest, you know, or even just nothing more than a curiosity, and those things led to really big things that I could never have predicted for myself. You know, sitting back as a as an undergraduate student trying to plan out my career. But the biggest thing for me, you know, I think along the way, every step has contributed to my growth. And I have a lot of growth left, you know, the ironic thing is, the more you learn the more you realize you have a lot more to learn. And so that certainly has been my case, and I've been surrounded by incredible engineers along the entire way. So my biggest, I guess word of advice would be is to surround yourself with with capable and caring mentors people who have established themselves who care about your career. So all of my success can, you know, as I look back all of my success can be linked to, you know, the giants of the industry that I stood on their shoulders that they trusted me they gave me responsibility. You know, they showed me, you know, a good way to get things done, and then let me do it they gave me some, some room to kind of figure it out I guess on my own as well. And it really comes down to the people it's the people I've met along the way that really have made the difference in my career, and I owe so much to each of them along the way. Well, I love that. It's great. Absolutely love that we we probably have mentorship come up at least once in every episode and for our young listeners out there who don't currently have a mentor, you've heard it again, please go find someone who shares interests or that you admire or you know we've got this every single time I swear to God but it's so nice to always hear that again when it's especially unprompted, we will pay him the $5 later. But it is it's so true, it absolutely is so true. Wonderful. Jason, this was just nothing but fantastic I learned so much. I never took a steel course that's my big dirty secret instructional engineering never took a steel course so I feel like too late. I think I've resigned myself to my base material of choice, but I appreciate it and if I ever do have questions I know to go to now. Absolutely. Perfect thank you so much for joining us and I want to say one more thing really quick I really admire how much you continuously give props to your team members. There is one civil engineer that I work with he's one of my very dear friends and I volunteer with him to get kids involved with Sam all the time and he always preaches to high school students that there are no more great inventors like you don't hear about a one single engineer one single scientist who you know reinvented the wheel or did something amazing it's always teamwork and especially with as specific as our roles get especially in technical roles nowadays. You're you are a niche of a niche of a niche and when you bring all these different people who have certain expertise in very different aspects and bring them together is when big things happen and I think it's so. I think it really speaks volumes about you as a professional that you recognize your teammates contributions and that you know they're clearly people who you admire and that you learn from. And I think it's fantastic that you're able to showcase that level of teamwork and even the fact that you compose these articles that you bring them into the fold and make sure that they're recognized so. Another another great tidbit for everyone to take away from this is that it's always a great thing it's always in style to show gratitude to the people that you work with and that help make you grow as a professional as a person so. All right Jason where can our listeners connect with you and follow you and hear more about your awesome steel knowledge. Yeah I'd love to hear from anybody who's got follow up questions or curiosities or wants to you know just contact me for any other reason that you can find me on LinkedIn. Or also you can find my contact information listed on the National Steel Bridge Alliance website, so I'd be happy to hear from anybody. Maybe he'll even mentor you. Yeah, yeah absolutely I'd be happy to be a mentor if somebody feels like I can offer them some support. I'd love to do that so you bet. That's awesome thanks Jason. I really appreciate this it was very nice chatting with both of you so thank you for reaching out and I hope we can stay in touch. Absolutely. You too Jason thanks so much. Thank you so much. We hope you enjoyed the episode today we would love to hear your feedback comments and or questions. To leave them please visit structuralengineeringchannel.com there you'll find a summary of the key points discussed in today's episode as well as links to any of the resources websites or books mentioned. Don't forget to subscribe on Apple Podcasts or wherever you listen to your podcast. Until next time we wish you the best in all of your structural engineering and economics.