Current state of the practice for bridge hydraulic and scour analysis tools

[Applause] okay uh has worked for the Federal Highway Administration and prior to being with the federal High Administration was in the private sector so has experience in both the public and private sector and with that please give a warm welcome to Scott [Applause] all right thanks really appreciate I can't tell you how much I appreciate Cornell and James and the smart folks at the lab and you guys should all be very appreciative of the resource center I'll tell you why um before we can deploy any technology from the lab these guys have to be able to bring it down to our level and explain it to us before we can deploy it to you so that's there's a lot of that goes on behind the scenes that most people don't get a chance to see so these guys do incredible work at the lab and I'm fortunate to have a chance to work with them so my uh intent today or my objective is simply to share with you the state of the practice of bridge Gower and Bridge Hydraulics and I suspect probably most of you are familiar with a majority of this but you'd be surprised they still run into many consultants many states that are not familiar with the latest tools and they're still doing some things that are really outdated so bear with me I'd suspect many of you at least get to see something at least one thing that's new today so here we go um now I don't have Joe's dinosaur my disclaimers but I have to note this that I think our legal counsel in the resource center is different because I have four bullets required and Joe has two in headquarters if it gets any more we're going to start bringing legal counsel with us to give part of the presentation we tried that and we had to put at the beginning so anyway I know I know maybe it's just me it's just me right so all right so I've got um here's an agenda for what I hope to present today is not to give a thorough history but just to bring a couple points up and highlight available resources some have been noted by others but I just if you're doing Bridge scour analysis there's some things you need to know that are available we'll talk briefly about the whole 1D to 2D modeling I'll talk about benefits of scour with 2D modeling and then we'll spend a little more time uh talking about tools that we have available to extract variables to be able to compute scour very efficiently for multiple profiles and then I'll close out with a couple notes on settlement transport modeling so again not a comprehensive history of bridge scour but I like to point out to everyone that we have been recommending two-dimensional hydraulic modeling for bridge car analysis since 2012. it's been 10 years now all right so that's in heck 18 if you don't know read closely so we have been recommending it now granted things have come a long ways in the 2D modeling world and that's a couple of these other bullets to highlight in 2013 we recognized that the model we had back in 2012 was not you know very user friendly and it wasn't easy to use it took a long time to run and so we started doing what we could at that time to improve your analyzes and make it more efficient so we partnered with the Bureau of Reclamation specifically Dr live who's here today to improve the model side and then we also started working to improve the interface side and then later on in 2017 through 2021 hopefully we reached all of you if you haven't heard about EDC change we missed the boat somewhere that was a four-year period where we had a lot of resources to promote the use of 2D modeling to improve Bridge Hydraulics and that's not over the program we were beyond the program but those efforts continue um and then in the midst of that 2017 we added the bridge scour tool um in SMS to use for srh2d and then I just closed out here with a point about how many states are using 2D modeling because I get this question quite frequently especially from states that aren't using it yet or using it for scour the last you know do we really have to are other states doing this and the answer to that is absolutely maybe to vary in degrees and I say 45 States using 2D modeling that may not be on their entire program but they've used it to some degree now there are some states that are all in they're using all 2D modeling they're doing all their scour analysis with with uh with 2D and so we still have States some are still using 1D modeling and it's it's really a kind of a scatter so hopefully for those of you that might still be holding onto the 1D modeling I can maybe encourage you to continue to step into the current state of the practice so I don't want to spend a lot of time here Paul pointed out our documents Tech 18 2023 and hds7 but if you're not if you're doing Bridge scour and you're not familiar with all of these resources you need to be so the training courses are searched all the documents and then each of our documents has a accompanying training course that goes with it and then also I want to highlight recently over the last year we meaning the resource center had put on a bridge scour Workshop so an eight hour Workshop over two days that's not in any way meant to replace our training course but it's been a refresher for some and it's been an introduction to scour for others now we only did that intentionally for state DOT staff and the division offices just because the demand would have been so high and we wanted to be able to answer some questions so we've tried to put the word out through your States to say hey contact your consultants and put this out there and it's been partially successful so I want to let you know that that Workshop is on our federal highways Hydraulics page so we have links to all the recordings and all the resources so if you just simply to go to your web search fhwa Hydraulics it'll get you our page go to the bridge scour Tab and you should be able to find that so there's a lot of good information there a lot of the stuff we shared was new to people and it shouldn't have been so even if you think you're an expert at scour I would recommend going back through that and taking it as a refresher and then these last two things are the only two things that aren't not on our website but if you're interested in certainly contact me the bridge scour tutorials and the uh a link to the bridge scour tool that I'll talk about and the instructions so I'll talk about it later on so that's a lot of stuff I always like to include this slide my presentations when I start talking about 2D modeling so if you're still using 1D modeling I want you to appreciate the number of assumptions that are being made all right and then as you transition to 2D modeling we overcome a ton of assumptions okay and as you've heard from other presentations we don't get rid of all the uncertainties but we overcome quite a few assumptions and so again 2D modeling because of a lot of the tools and Computing powder and just the models are developing there are very few reasons now not to move into the world of 2D modeling somebody I'm sure would bring up FEMA but even that is changing significantly so hopefully you're hearing that if you're still a holdout man I'd love to work with you I mean one of our roles in the Resource Centers to provide training of technical support let us know how we can help you you've probably heard from other presentations I think by Dr zundel um and you'll later hear from Dr Young Lai that there have been many advancements both in SMS and the interface as well as the SRH 2D model and they continue to be added in every new version I want to highlight on just a couple things that relate specifically the bridge scour and hydraulics namely a 3D Bridge tool has been added in the last two versions and this is pretty significant it adds we're not doing 3D modeling so don't get me don't mistake that it's still 2D modeling but what this allows us to do is enter the 3D Bridge geometry so now pressure flow can be computed at every element relative to that low cord surface at that element right so you can enter variable Bridge geometry Arch Bridges slope Bridges which has been a limitation in the past so this has come with the with the latest investments in SMS and srh2d and so I think this is this is a significant Improvement in evaluating not only more accurate detail Bridge Hydraulics and scour and the tools for developing meshes specifically around Bridges continue to be improved as well Dr zundel talked about this we've heard from States how long it can take to develop a good efficient mesh through a bridge section that's stable that results in stable Solutions and so we've heard that and so we've continued to focus development this an area in this area and so now we have a automated tool so you simply Define the center line of The Bridge Center Line of the piers give it some parameters and tilt to go and it generates that mesh that mesh around the bridge automatically and can handle skewed Piers skewed abutments all right and so this will I think this will again this will really improve the user experience and prove the results in the sky analyzes as well and by the way I didn't give links to all this but we there's tutorials on all these features as well so if anybody has questions certainly feel free to reach out to me on this now as we talk about 2D modeling I often get the question well hold on how are we improving scour analyzes if we're still using you know scour equations from way back when okay fair question from going from 1D modeling to 2D modeling we are significantly improving our representation of the flow distribution all right water surface elevations and velocities so even though we're extracting averaged hydraulic conditions from our 2D models it's still drastically say significantly different than what we had available to us in a 1D model Okay so don't hold on to your 1D Model results because you think it's you know we're still using old scour equations cornellos and James are working to improve that but meanwhile get up to speed in the 2D model and once they have the scour Decay functions all figured out and we're going to be we're going to be cruising so and also I believe with the 2D modeling the tool with the tools that we've added to the 2D model the efficiency of scour calculations has also greatly improved one of the things that we've stressed for years but we've recognized it's been a challenge is evaluating scour at multiple flows so we can truly assess worst case scour I know we've been preaching that but many are still evaluating maybe only the Q100 or the q500 it's it's admittedly it's fairly rare to see states that will that will evaluate scour for more than two flow conditions well in reality it's maybe it's uh you know oftentimes you might see worst case scour at the q500 but that's not always the case and so we're certainly recommending that everybody look at say four five or even six flow conditions to evaluate that worst case condition and with these new tools it's a lot easier to do that this is not a big lift all right so let me walk through this just a little bit and so one of the things I'm going to be speaking specifically to is the new bridge scour tool I say new it's not new sorry this is the bridge scour tool in SMS it continues to be improved but it's it's basically a new coverage in SMS where the user draws an approach section which does require some judgment a contracted section across the bridge opening identifies the bridge stations the bridge or sorry the bank stations the peers and the abutments okay just one time and then when you execute the bridge scour tool all of the average hydraulic parameters from the main Channel and the overbanks are extracted for scour calculation and either your own spreadsheet or the hydraulic toolbox okay and so a a key Point here and this is one of the tedious parts of computing scour is that if you have to make adjustments for skew to your peers and for your Bridge relative to the flow not only is there judgment involved in that it also takes time all of that's automated all right so you really can compute scour for multiple flow profiles in a very short amount of time compared to what it used to take another thing I want to point out here is that it's the this tool is now to the point where all of the data as is entered in SMS as attributes so peer shape the pure length um abutment type vertical or sloping all those things are entered in SMS so when you get to the hydraulic toolbox you don't have to go through and reset and enter all of that information it's all there for each profile so just to highlight a couple things this is what the actual dialog looks like in SMS to highlight you know you can pick one or several profiles at one time uh you specify a soil gradation now currently it's only there's a limitation of entering one soil gradation we typically enter that it's it's technically representing the approach section but many use that to also represent the contracted section that's that's another discussion in the future you'll probably see that expanded you specify the mesh geometry the different flow scenarios you want to extract from uh you you don't have to have a 3D Bridge but if you do have the bridge in there it extracts all the bridge geometry for the plotting and for pressure flow calculations and so on and you you enter um oh the abutment scour type that you're going to use and see use for the NCH or P method select an output file and hit go another good thing is that you probably can't read this but you're exporting a hydraulic toolbox file and just in case you don't have the right version of the hydraulic toolbox installed we've done it for you all right so it's you can launch that right from SMS to point out for those of you that still use your own spreadsheets and I still I appreciate that that's great there is a this little view values button you can hit that and you can copy values for each profile to your spreadsheet I still love folks that that check the hydraulic toolbox and tell us when they find errors because it's not completely error free so continue to do that and we will continue continue to improve it so a couple highlights here is that nearly all the entries in the hydraulic toolbox are Auto populated for all of your profiles so all the white boxes in the hydraulic toolbox for all the pro flow profiles there's now a pull down box in the hydraulic toolbox that you can cycle through each of your profiles now the there's one exception or I should say two exceptions long-term degradation is not is not addressed in SMS you got to evaluate that check the box and go through evaluate long-term degradation and currently the all of variables for pressure flow also are not transferred we're working on that so that's that's really the the only exceptions to what is not automatically transferred to the hydraulic toolbox but expect that uh fairly soon and then not uh almost wrapping it up here um just to highlight the some of the capabilities that have come along and the hydraulic toolbox in the last year two years is we now have a summary table all right so the hydraulic toolbox used to just calculate scour components and it was up to you as the user to figure out how that equated to the elevations and locations so now that you've exported geometry from your 2D model and your Bridge so all of your scour depths are presented but also your total scour elevations are also included as well and that can be copy and pasted into a report and helpful to use we've also continued to try to improve the plotting capabilities within the toolbox even though you can plot all of the results on one that gets really busy it's best to do that individually for each profile all right but I want to close out just with a kind of a something uh some food for thought we're not at any way trying to tell states to start doing their scour with sediment transport but as the set of a transport capabilities have become more and more readily available in a 2d model I've found it to be a very useful way of confirming or help helping to verify scour results when they seem unbelievable this is just one example uh a fairly simple Bridge highly contracted flow um I guess it's not always here on the index slide shows the dot contacted me and said you know we're Computing 30.3 feet of scour we just don't believe it Federal highways you know heck 18 methods are way too conservative well I said you know I'm not going to disagree with you but contraction scour is a pretty straightforward calculation you know especially in this case you can look at the Clearwater scour or the live bed and so so this is an easy case I can apply this with Center transport 2D model if you run the 2D model just assuming like uniform flow or equilibrium conditions so you run a peak flow and you let that thing scour until it stops scouring computed 35.5 feet of scour transport so that's not bad okay so my point is is that when you run into a case where you think the scour is unbelievable or if you have a complex case maybe different tributaries coming in where our our heck 18 methods may not be appropriate we do have tools that can be utilized now with not a ton of extra effort it's not just as easy as hitting another button but if you have sufficient sediment information this is certainly something to consider in the past we've really not had a lot to offer to States so that looks like a tough case let's just assume Clearwater scour and move forward I think we can do better now okay so just something to consider um we do have I think Laura mentioned this earlier we do have videos coming out for settlement transport so stay tuned they're going through our legal review right now um but it is something we want to start making available to States for those that are interested so with that is my contact information please feel free to contact me with any questions and I could certainly entertain any questions you guys have now I know I'm the fifth speaker it's time to go so so yeah so in that in those figures at some point hopefully there's an opportunity to include multiple layers of different soil types absolutely this is yeah it's a good point so this is a simplified analysis they had they had one one sample whether it's correct or not that's what they computed scour for so I assume that material was you know for uniform throughout it's a good point yeah yeah so oh yeah to clarify so that the model can handle stratification but okay I didn't know that as you noted most most States aren't collecting that data yet so that certainly would be helpful to improve the analysis any other questions all right well thank you much [Applause] well yeah that concludes the session unless somebody has any questions for any of the speakers during this session I'm sure they're more than welcome to stay afterwards otherwise

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Id: pNaDv5ey7QE

Length: 21min 27sec (1287 seconds)

Published: Tue Mar 21 2023