All right, guys, we're going to go ahead and get started. So happy new year to everyone and welcome to the first Post-Tension Institute webinar of 2025. With this being everyone's first full week back after the holidays, I know we're all adjusting back to the real world and hopefully today's webinar will be a nice little break to that first week of a grind that we're going through here. My name is Kyle Boyd and I'm the moderator of today's session. I'm also the chair of the Education Committee for the Post-Tension Institute. That's EDC 130 committee. That's the committee that hosts this monthly webinar. For those of you who it's your first time joining, we do have this webinar at the same exact time every single month, same time, same date. And so that's that second Wednesday of the month, which is IE today at one o'clock Eastern 10 o'clock Pacific time. So we encourage you to log in every single month. It's for free. You get continuation, continuing education credit. If you miss a webinar, we do record them. We do put them online. So there's 12 webinars from 2024 that are upload, they're online right now. You can go watch them, take a quiz at the end and get free continuing education credit if you're trying to do a little catch up on your CEs there. And then this one that we're doing today, we're going to record it. We're going to put it online. So if you have to step away for whatever reason, you can step away, a colleague misses it. You can just go watch it online, take a quick quiz and get that credit. So the last couple of webinars we did, they're focused on slab on ground. We had a lot of interest in there. We had a lot of great feedback from that, and we're going to do several more slab on ground webinars in 2025. But today we're going to go elevated and we're going elevated to discuss parking structures. So the parking structures, this is a hot topic that we have within the industry right now. I hear a lot of conversations in the hallways around parking structures there, and it has to deal with the electric vehicle weights and they're notably heavier than your standard vehicle. So the question has really become, do we need to design for heavier loads there? So today we have Walker consultants presenting on this exact topic. And for anybody in the industry, you probably know who Walker is. They're very well-known consultant and one of their expertises is in parking structures and they do parking structures all throughout the US. So before we go too much further, we got to go through just a couple of generic slides real quick, and then I can introduce the speakers and the first one sponsorship. What we're doing is we are allowing sponsorship opportunities because we've had several requests for that over the past year for these webinars. You can sponsor it. You can get your name out there. It helps keep these webinars free to the general audience. And it's just a great way to be a part of the post-tensioning Institute. So if you're interested, there's a link there. You can also reach out to us at the end and we'll give you some more information on there. So then continuing education credits. Like I said, you get a continuing education credit for being a part of the webinar. Today's webinar, it's through RCEP is where you'll get it. As long as you are personally logged in with your email and watching this, you automatically get that credit at the end, as long as you stay on for that entire duration. Once again, like I mentioned earlier, if you miss it, all you got to do is go online, take the quiz, watch it, take the quiz, and you'll get that. And you can do that for any of the ones we did in 2024 as well. So there's 12 of them there if you're doing that catch up game right now. In addition to RCEP, we are doing AIA credits this year too, and that's new for 2025. So we have all that linked and figured out on that. So moving on to copyright material, this is just a slide we have to put in that says, don't copy anything we're putting here. If you want anything, let us know, we'll be happy to try and accommodate you. We do not provide PDFs of the presentation, that's a question we get every single month, but you can go watch it, see the whole thing online on the video there. And then from there, the webinar protocol for today. All the attendees, you guys are muted and you're in listen-only mode. So we can't hear you. We can't see you. If you have questions, you need to ask them through the Q&A feature at the bottom. So you ask that question through that Q&A feature, and then we'll be able to ask them at the very end. I'll be moderating those questions there. So that's how you ask them instead of raising your hand or interjecting, and we're going to do all the questions at the very end. We already talked about, you just need to be on the webinar to get that credit. It's recorded. So I think from there, we're good to introduce the speakers at this point. So our first speaker today is Leslie Jo Hertz. She is the managing principal for the Walker Charlotte office. So we obviously have a very well-established, very senior person from Walker Consultants presenting today. She's got over 20 years of experience in the consulting industry. She also had a very impressive career at Charlotte Douglas International Airport, managing a lot of their capital improvement programs. So very senior person presenting. We always have very heavy hitters, in my opinion, presenting. We try and find the best out there in the industry, and we obviously found one today. The second speaker is Rashad Amid. Rashad is the vice president, one of the vice presidents, and the chief structural engineer at Walker Consultants. He's led the structural group. He's out of the Chicago office, obviously leads that group, and all the other Walker officers when it comes to the structural portion of the company there. He's got over 30 years of experience. He's very involved in the concrete industry. As you can see, he's a fellow in the American Concrete Institute in ACI. He's a fellow in PTI. He's part of PCI. He's a PE. He's an SE. So that fellow really means he spends a lot of extra time working and volunteering for PTI and ACI. So again, a very well-established individual, and we can't think of any two more qualified individuals to present today than Leslie and Rashid. So with that, I'm going to shut up, hand over to Leslie, and let her present on electric vehicle weights. Hello, and everybody, and thank you, Kyle. Specifically today, we are, I have to move something here, hold on, there we go. Specifically today, we're going to talk about current trends in vehicle sales and weights. We will define the design vehicle in the 85th percentile. We will also discuss the impact EVs have on curb weights of passenger vehicles. And finally, we will get to how this all affects design loads. There's a general conception that EVs weigh more than ICE vehicles, and it has been questioned whether or not code-described design loads should be increased. Well, it is true that the largest EVs today, such as the Hummer, are heavier. However, our analysis will show that the appropriate weight for design is significantly less than that of using the heaviest vehicle out there, such as the Hummer. As you can see in the brief example from 2023 data, that while the lightest and heaviest battery electric vehicles are heavier than their counterpart, ICE vehicles, when looking at all passenger vehicles on the road, the 50th percentile electric vehicles actually larger, pardon me, lighter than the 50th percentile of all passenger vehicles. So let's look at the details and see how that can happen. We'll start with an EV sales update. I will note that the year-end 2024 data is not yet fully available. However, we have included what we can, and you can see that EV sales have been and continue to increase year over year. Currently, the EVs are 9.8% of light-duty vehicles, which are vehicles less than 8,500 pounds, and they exclude trucks with six or more tires or more than two axles. We expect light-duty vehicle sales to be 15.8 to 15.9 million in 2024, which would include a really big surge from this past December. Consultants are expecting about 16.3 million light-duty vehicle sales in 2025, which would be less than 3% growth. In the EV tax credits, if they're rescinded as we expect them to be, it will take time to take effect, and we may see that the EVs will have a 10% market share, but with the growth in EV sales year over year, will be less than what we have seen in the past. So in this slide, you can see here on the right that the growth of plug-in electric vehicle market share from 2020 to 2023 averaged 2.3% per year. While that seems disappointing, market share is still growing, it's just that the growth has not been as fast as manufacturers and others planned, forecasted, or actually produced. Our current high projections for expected EV sales in 2040 is 85% of the total vehicle sales, but the number of EVs on the road will still only be 42% of all vehicles on the road. So looking at overall trends for the vehicle weights, ICE vehicles have gotten lighter due to fuel economy strategies, which is a really good thing, but this has allowed manufacturers to increase vehicle size and keep them at the same or even lower weights. As you look at the graph, you can see that a reduction in the less than 3,000 pound category since before year 2000, which is the dark blue line here, there's also been a reduction in the less than 4,000 pound category since 2016, and that is the light blue line here. The majority of those changes since 2016 are reflected in the increase of the less than 5,000 pound category and a slight increase in the less than 6,000 pound category, which is the orange and the yellow lines. The greater than 6,000 pound category has been pretty stable and very little change since 1996. I will also point out that trucks have increased from 40% to 75% of all passenger vehicles on the road, and overall 70% to 75% of light vehicles sold in the United States are between 3,000 and 5,000 pounds. So given all that, what should we design for? And the answer is the design vehicle. So let's talk a little bit more about that. To give you a little background, Walker has used the design vehicle approach to parking layout and design since the 1980s. This type of approach is based on accepted traffic engineering practices that use a design vehicle for road geometrics and is a widely accepted method for parking and road design throughout the world. Walker's theory of a parking design vehicle has been adopted by the Parking Consultants Council of the National Parking Association, and it has also been published in the ITE Engineering Handbook. The design vehicle is intended to reflect the 85th percentile in the range from smallest to largest, which means 14% of vehicles are larger than the design vehicle and 84% are smaller than the 85th percentile vehicle. For parking layout dimensions and turning radii, we base the design vehicle on footprint, length and width. For height, which is mostly used for automated or mechanical parking, we base the design vehicle on shortest to tallest, and for weight, it's based on lightest to heaviest. When looking at parking layouts and loading scenarios, the risk of finding one parking space with vehicles larger than the 85th percentile vehicle parked on either side and across the aisle is 0.3%. It is really, really small. So there's really no easy way or single source that provides vehicle sizes on the road, and we have to figure it out ourselves. To do that, we monitor annual car sales using sales by model information published in Automotive News, and then we research the size of each model for footprint, height, weight, and calculate the 85th percentiles for each of those categories. It has gotten harder over the years, and these days we really have to do some sleuthing. It takes a lot of time, but we are able to get the information and compile it and add it to our database. Our current database goes back to 1996, when we added light trucks, which included crossovers, vans, SUVs, and pickups. We also made adjustments to the data in 2016 to account for the percentage of pickups and vans that are classified as heavy duty and used for commercial purposes rather than personal transportation. These are the vehicles that we talked about over 8,500 pounds. The average age of cars on the road is about 12 years, and so it takes a while for the changes in the sales to be reflected in the actual cars on the road. As a result, we monitor for trends and only change the design vehicle when it appears there is an established trend. Every year, after we evaluate the sales, we determine the 85th percentile in sales, but the design vehicle, which we select based on our best judgment, only changes every once in a while. When we do change the design vehicle, it likely will not represent the mix of vehicles on the road for at least five years, so it's very forward-thinking. Now, let's talk about how the 85th percentile dimensions have changed over time. As you can see from these graphs, it has not changed much. This big graph here talks about length and width, and it has been very stable over time. We changed the design vehicle for parking in 1998 to reflect the increasing sales of light trucks, and you can see where the length got shorter by this blue line, but the width got wider by the red line, and the current design vehicle, which has been pretty steady, is 6 feet 7 inches by 17 feet 1 inch. The 85th percentile height has been between 72 and 74 inches, which has been slightly ticking up since 2014 here. It's currently 76 inches. We don't really use the height design vehicle, since most minimum height clearances are actually set by building codes and ADA requirements. The 85th percentile curb weight in sales has varied over the years. It's gone up and down quite a bit, and if you don't know, the curb weight is the weight of the vehicle without passengers or cargo. You can see weights increasing with only slight increases year over year. There's a slight jump in 2022, and we'll have to see if that is sustained. So looking a little closer at this curb weight, the 85th percentile curb weight has been between 4,000 and 5,000 pounds since 1996, and has only recently increased about 5,000 pounds. What has changed, though, is the increase in sales of crossovers from cars and minivans. Crossovers are like SUVs, but they are built on car platforms, so they are generally wider than cars and affect parking dimensions, however, they weigh less than the SUVs and pickups. The predominance of crossovers contributes to the increase in the 85th percentile curb weight, but not nearly as much as the shift in the number of light vehicles on the road, which, if you remember from earlier, has increased to 75%. So at this point, I'm going to go ahead and turn this over to Rashid to relay all of this design vehicle information to applying it to loads. Thanks Leslie. So here you can see that you know the 85th percentile weight and just want to recap what Leslie Cho just said about that the design vehicle load. So the way the design vehicle work is we take the 85th percentile of the weight and this is how we calculate those 85th percentile weight. Now you can see there is a slightly uptick on the weight of the car in the last few years recently. And one of the primary reason for that is the sale of the light truck. As you can see the light truck sale has gone up significantly over the last few years. So it's not due to the EV but it's due to the light truck weight. Okay next one please. So I'm going to go over some history on the code how the live load has been defined in the code and I'm going to look for the last 25 years since the IBC 2000 introduced. So starting with the IBC 2000 the uniform live load was prescribed as 50 pound per square feet. However they do allow for the reduction in the live load up to 40 percent max for the horizontal members and 60 percent for the vertical members. And then the concentrated live load was 2,000 pound. And then the horizontal vehicle barrier load that was defined as 6,000 pound at 18 inches above the floor. Then in IBC 2003 they came out with reduced the live load from 50 to 40 PSF. They were still allowing you for the live load reduction 40 percent. Now if you take the 40 percent live load reduction they will bring the 40 PSF down to 24 PSF for the horizontal member and that's how I the issue a 2004 supplement and restricted the live load to a max of 10 PSF reduction. So that means you can go below 30 PSF live load. And then the concentrated live load they increased to 3,000 pound and the horizontal load for the barrier load that's 6,000 pound at 18 inches above the floor. So there is no change on the horizontal barrier load. In IBC 2006 they kept the 40 PSF uniform live load. However they don't allow you for the live load reduction unless if the member is supporting two or more levels. That means like beams and gutter typically the floor will not be allowed for the live load reduction. However columns and foundation if it is supporting more than two level you could reduce up to 20%. The concentrated live load still same 3,000 pound and then the horizontal vehicle barrier load still stays same as 6,000 pound at 18 inches above the floor. IBC 2009 they kept the uniform load at 40 PSF. There was no reduction same thing as the previous the 2006 code. No reduction for the horizontal members and up to 20% for members supporting two or more levels. The concentrated load still kept as same as 3,000 pound. And then the maximum horizontal load this is the first time they introduced the 27 inches above the floor. So they have 18 and 27 inches. You have to apply the horizontal load to design. And then after that since 2012 up until 2024 there were like five version of IBC codes and there is no change there. They kept 40 PSF uniform load. Same as no reduction for the horizontal and up to 20% for members supporting more than two level. They kept the same concentrated load as 3,000 pound. However the horizontal vehicle barrier load the previous one was 6,000 at 18 and at 27. This time they changed from 6,000 pound between 18 and 27 inches. It could be anywhere between 18 and 27 inches. So this has been there since 2012. Next one please. So this is a busy slide but I will go over this one. So this is what's happening. The reason for this slide is that I want to show you 25 years ago what we were discussing and we are about the same place today also. The difference is at about 25 years ago the SCV was introducing it in the marketplace and then the people were concerned about that SCV will increase the live load. And there was an article in the middle of this slide you see there's an article published in March 2012 in Concrete International by Javed Malik and he was suggesting to increase the load increase the point load by 50% and uniform live load he was suggesting to double. That means back then the live load was 50 PSF that he's suggesting to design the garage for 100 PSF live load uniform live load. And then he has looked at different structural system and that's how they he come up came up with that bad one based on the SCV load. Obviously that was you know extremely high. So then our Walker people we wrote a rebuttal white paper which was published in Concrete International in September 2002 issue. And there we also discussed about the design vehicle based on the 85th percentile. We have gone with we have looked at different geometry, different configuration, the way we're going to park the car, different structural system, and we recommend there is no need to increase the live load back then. Not doubling to 100 PSF. And then at the top the two the first two paragraph this was the research carried out by University of Illinois at Urbana-Champaign two professors Wen and Yao. What they have done is they did a research for nine parking structures in three cities Chicago, Boston, and Urbana- Champaign. So they looked at those nine garages. They went there they took all the data from those nine garages based on what were the car parked at different times. And they came back and they did the numerical analysis based on that. They also look into the dynamic factor with the you know with respect to the different slope six percent ten percent. So they did all the numerical analysis and based on that what they have prescribed is that the live load needs to be 40 PSF. Uniform live load needs to be 40 PSF and the concentrated load has to be 3,000 pounds. That was a recommendation based on the research done by Wen and Yao. Their paper was published in the Journal of Structural Engineering ACI Journal of Structural Engineering in March of 2001 and that was adopted by the IBC 2003. So since then the uniform live load and the concentrated live load stays the same. The only thing they have changing was the horizontal load you know between 18 and 27 inches. So the reason for this one is to show you that 25 years ago when SCB was introduced in the marketplace you know we were talking about the same thing that it will increase live load on the parking structures and all those things. And by the time we did all the research and everything we came back no there is no need to increase the live load. Today we are on the same platform basically the only thing changes SCB replaced by the EV and again we are talking about the same thing. Next slide please. So this is the parking layout which we have looked back then and we have looked at the precast framing system, one-way cast-in-place post tension framing system and then the two-way conventional reinforced concrete slab system. So the first to the precast and the post tension those are the most popular framing system in the parking structure. So the post tension we looked at a 24 by 60 foot grid and the way we have done is that we have we use like an 8 foot 6 inch install for the parking the width and we assume that every single install has been there is a car park in that every single install in a particular way and there are the driving aisle it's filled with the car there's two car both side there's two car going back and forth they are crossing each other so this is the maximum you can fit in any layout and all these vehicle weight was we use was the 85th percentile obviously that's that's conservative but we look with that system. Next slide please. So the so the what we found from that research from that analysis is if you take the precast framing 36 by 60 foot bay your live load is about thirty four point four nine pound per square foot. If I take the post tension structure with 24 by 60 foot bay and this again same thing you have car park on the on the both side of the stall and then there is car crossing both side the live load is thirty eight point eight pound per square foot and then we look at the conventional reinforce with a 30 by 30 foot bay and then different other system even with the steel beam and there with the precast frame and the steel frame with the post tension slab. If you look across our weight is varies between 30 and 39 point per square foot. It's still it's well it's below the 40 PSF a quote prescribed load. So based on all these analysis and what we have been seeing you know our rationale is that there is no justification to increase at this point the EV weight you know yes it is higher but if you look at the 85th percentile weight of the EV it's very close to the ice curve. Next one please. So I'll give it back to Leslie Jo so she can take it over from here to the end. Okay, there we go. Sorry, I'm not a good driver here today. All right, well, thanks Rashid, I appreciate that. So with all that information, with loading electric vehicles, design vehicles, sales, what's coming around the corner? And without question, technology improvements and car design innovations around batteries, stability, fire risk, temperature resistance, and range will most certainly affect electric vehicles and their overall performance. Well, this quote on the right hand side is a little old at this point. It does confirm that these types of improvements are coming and Toyota's president and CEO noted that they have been making breakthroughs, improving durability and performance of solid state batteries and expect to have production of this type of technology in cars by 2026 or 2027. And I think there's other types of battery technology that's out there also. The car companies are committed to EVs as there is a world market. It's not just here in the United States. So even when all of these technology improvements are combined with our projections of EVs on the road in the United States, it's gonna take a long time for the design vehicle by weight to increase simply due to the weight of batteries. So what are the takeaways we'd like to share with you and for you to take today with you is that we're gonna continue to see more and more EVs on the road. That's not a question in my mind. The 85th percentile vehicle has been pretty steady since the late 1980s. However, there has been an uptick in the weight since 2022 and we will continue to monitor that to see if it is sustained. And if it is, then we'll make adjustments as necessary as we see that trend. We'll monitor, we monitor annual sales to determine the 85th percentiles each year, but the design vehicle only changes when we see a definable trend. And when evaluating a loading scenario that puts the design vehicle in each parking space at curb weight and in the drive lane with cargo and passengers, the actual live load is consistently less than the current code prescribed live loads, regardless of the base spacing or structural system. So it's our conclusion that at this time, there's not a justification to increase in design loads to reflect EV weights at this time. So I think we'll hand it back to Kyle and open it up to questions. Great, thanks guys. So we've got quite a few questions here. Some of them around EVs, some of them around parking structures and kind of where you guys see them going here in the future. I'm sorry, I'm the worst driver, sorry. So the first one with EVs has to deal with fire concerns. So obviously we've seen a lot of stuff on the news with electric vehicles and fires and challenges put out, and there's been some discussions out there. Do you guys have any thoughts on localized fire resistance for where there either is EV charging stations or overall fire resistance to structures that are going to have notable amounts of EVs in them? Well, I think it's a conundrum because a lot of communities are requiring that you put charging stations in parking structures and for residential, for parking structures that serve residents, residential buildings and apartments, that makes sense because that's where people should be charging. We've been trying to minimize what's actually installed in other public type or office building type servicing parking structures because of part of it is because of the fire rating because it is hard, they're hard to fight and they cause damage. You can't put out a fire, it has to actually do the chemical reaction for it to stop and they get very, very hot. So the building code is starting to, or has tried to put in more firefighting requirements, fire protection, but the water really doesn't do much. It just tries to prevent the fire from spreading. Rishi, do you agree with that? Yes, I can give you one example, Kyle, here in Chicago. There was a mall here, fashion mall near O'Hare airport and there was a EV car caught fire and what the fire guys have done is basically they just pull the car out of the garage and then let it burn outside an open lot and sometimes they use a fire blanket that's put on top of the car so it won't spread the fire to the other car. So they try to, basically they try to control it rather than to put it off, something like that. We've had clients here that put them on the roof level trying to minimize some damage and then, but the trouble is you have to use a crane to take it off the deck or tow it all the way out. So there are, we try to encourage if it's a campus location to put the EV spaces outside of the deck, if they can do it. Great. Next one, we have a couple of questions on this, but you had a slide and you're talking about you're seeing the increase in length of vehicles and how that's changed over the years. Do you anticipate seeing, there's certain guidance recommendations out there for turning radiuses, spacing of columns, parking width for the stalls. Do you guys see any trends in that slowly starting to increase to accommodate these vehicles with a higher turning radiuses or higher widths, higher lengths to them, especially those light trucks? Yeah, as it affects that 85th percentile vehicle, we would make those adjustments. But again, as you can see, the length has actually been pretty steady over the years and has not, well, there might be certain vehicles that get longer, the influence on all the vehicles out there at one time and its influence on the presence of vehicles is not that great. It's been pretty consistent. Sure. And do you guys see along that same topic, if you're doing a garage, that's a little more of a rural area where there's more of those 1500, 2500 series pickup trucks doing larger spacing on some of the designs or do you see them being designed for the same standards as you would in more of a tight urban infill location? I think we've had owners ask about that. And we try to look at what the presence is locally from some state data information on vehicles sold. And if we feel that it really does dictate a change, we will accommodate that. But a lot of those trucks don't fit because of the height requirements, the floor-to-floor heights, right? So they're not even getting into the decks, so. I know personally, for me, that's always been a challenge driving a work truck into an outside park and can't go into a garage, so. Right, right. And when you do that, you're adding costs to the parking structures and clients, owners, don't want that either, so. Right, right, right. Absolutely. Another one with the increase in heights, we got two questions that have to do with crash barrier protection on there. First one being with the increase in height that we're seeing, do you guys anticipate to ever see a change in the code of that? I believe it's that 18 to 27 inches where you have the impact zone. Do you guys see that ever getting elevated more? And there's a lot of vehicles out there where your bumpers are starting to get higher and higher. So what's your guys' take on that? I think we're still keeping the 27 inches. And I don't think there is a, I mean, I know there is a research starting recently at University of Colorado Boulder and University of Massachusetts. They're going to investigate some of these live load uniform. But I don't think they are looking into the horizontal load, you know. So I would say at this point, they're still keeping 27 inches. But that's a good question. And that's something probably we should be looking at, you know. No, I mean, you definitely see, you go into a parking garage and you see several vehicles there or even an external parking location there are either jacked up a little bit or they have that higher bumper location. And you kind of question, are you in that right range there? All right. Another question is that 6,000 pound load. So for impact with electric vehicles having ability to accelerate much quicker, creating a greater force that can be exerted onto there. Would you guys anticipate seeing that load or do you guys have any practice recommendations when it comes to that 6,000 pound load and possibly increasing that due to that accelerated, that quicker acceleration of a vehicle? Yeah. So again, this is a good question, you know. And currently like we're still following the ASCE recommendation, 6,000 pound. The, you're right, like electric vehicle could go much faster. So again, that's something research needs to be done. And I believe that one time PCC, which is a parking consulting council under NPA, they have some recommendation. They wrote a paper and there were some recommendation about investigating the horizontal load. So I think it's one of the area which probably needs some research. And I tell you a background of a 6,000 pound is it's interesting, like how do we arrive at the 6,000 pound? And so I'll just give you a little bit background. This is like back in 60s, 70s, when we were starting to design the parking structure, the, there was no definition about the horizontal load in the code. They don't tell you what is the horizontal load. There are some state code like Wisconsin, New York, and they have some number there, but they don't know what's the right number there. So in the 70s, the National Parking Association, NPA, asked PCC to go ahead and do some research that how do we come up with the horizontal load? So what the PCC has done is that they went to the University of Ann Arbor, Michigan, because they have a research center. I think it's like a ARC, Automobile Research Center. And I think they still exist. And they were working with those three big car companies in Detroit area. So the 6,000 pound, what the ARC come up with is that they were looking into the bumper. What is the maximum speed, the car speed that you can impact with minimum damage to the bumper? You know, if you come and hit some barrier, what is the maximum speed you can go without with minimum damage to the bumper? And that's why they came up with the five mile per hour for the speed. And then the PCC took that number five mile per hour, and then convert the potential and kinetic energy, and then came up with 6,000 pound. And that's what they recommend the 6,000 pound to the code body. So that's the story behind 6,000 pounds. So I think probably need some investigation. And I think the PCC has a recommendation to do some research on that, but that's all I know on that one. Sure, sure. Another question has to do with vibration in electric vehicles. You know, mass can assist with vibration control on there, but with the quicker accelerations and the horizontal forces that are being induced, have you guys heard any conversations or any thoughts on any additional vibration considerations when it comes to electric vehicles for the garage? I have not. Rashid, didn't the Yen and Wo paper look at that slopes? Yeah. Yeah, they looked up to 17.6% slope. So, you know, what happened that when the garage has a higher slope, people tend to go much faster. So typically, you know, five mile per hour, that's what the speed of the vehicle within the garage, but they tend to go higher speed on the speed ramp. So, but their recommendation is with this minor, this slope between five, six, 7%, usually there's not much impact on the vibration, unless if it is higher slope. Sure. We really don't design even the express ramps. We try to keep them below 16%. Right. From just a serviceability standpoint. Right. Okay, so one more. I have a couple. I can't really do the Q&A thing, cause I'm a panelist, but I had a couple of questions if you don't mind, Kyle. Yeah, I was going to say, I have one more for Rashid here about DC25 on there, and then I'll turn it over to you. So Rashid, for everyone, I may have missed this at the introduction to the presentation, but Rashid is the chair of DC25 for the Post-Tensioning Institute. And DC25 is the parking structure committee. So in addition to all the other groups that he's involved with, he leads the parking structure committee for the Post-Tensioning Institute. And since we have you here, can you give us kind of a general update? It's relatively re-kicked off new committee, but where that committee is, Kyle, what you guys are working on in PTI, what to expect over the next couple of years with documents? Sure. The one main thing what we are doing is there is a PTI publication, Design, Construction, and Maintenance of Parking Structures. So we are updating that document. That's our main goal to update in the next couple year. So that's one thing we have been working. We have formed the task group for different chapters and we are meeting on a monthly basis on that one. The other thing we are looking also is to give some, we have looked at different geometry for the parking garage, the width and the length. And based on that, we are trying to publish a tech note to guide engineer about, what is the most optimum base sizes in one-way slab system, two-way slab system, based on the material where you can optimize the material. So those are the things we have been working. Sure. So kind of like guidance towards fiscal economies with the structures themselves. Yes. Great. And then I believe this is kind of combination of a few committees, but there's quite a bit of information coming up with barrier cables, which is related to this. And I see Baxey has been doing a lot of work there. And as of now, we're planning on having him come in later this year to do a two-part series on some updates for barrier cable design as well for it. I wanted to ask real quick, if you don't mind both Leslie and Rashid. So one of the things too, that I've seen a lot more about these days, of course, is adaptive reuse. Not only taking an existing parking structure and changing its occupancy to something completely different and trying to make use of that, or just in your normal planning stages of parking structures today for the future, for their 75 year life or whatever may become of them. Can you shed some light on just some of the things you're seeing with regard to live loads and designing considerations based on the fact that in some cases, owners want to have a maximum flexibility for whatever may come later. And, or like you say, they're converting something they currently possess. Just some tidbits of information on loading conditions and the scenarios you guys have had on that, if you don't mind. I've never gotten past the initial conversation because once you start looking at it, the, you would be designing, it's something that might happen in the far future. And the owners and clients that are interested in it have been institutional because they don't know what that building might, that their building might be used for in 20 years or 50 years, but they've come to the conclusion that, or at least in my experiences, they've come to the conclusion that if in 50 years, that building isn't, they don't want to convert a 50 year old building or even a 25 year old building at some point, they just want to build a new building, right? And the challenges with it are that you'd be designing and spending money for twice the live load because you're changing from a parking structure loading to an occupied space loading, right? And it may not be used. So that adds a lot of cost. The drainage that's required for the parking floors is hard to handle. The floor to floor heights are hard to handle. You're just, so if you build it for a future building, floor to floor height, you're just adding costs that may not be in a regular parking structure. So that's been my experience. I don't know, Rashid, what have you seen? Yeah, it's pretty, but it's a hot topic also, the adaptive reuse. And owner are interested. There are some forward thinking owner, they would like to talk about that one. But I think 90% of the time when we discuss these things and when we put together, okay, because first of all, they don't know what they're going to convert that building. So what live load should we design for? Is it 60? Is it 80? Or should we go like 100? So if you put those factor in, then what happened that usually the cost gets so high that 90% owner, they decide against that one. Once we put together like a schematic thing. So that's what I work for my finding is that, yeah, they talk about that one, but when they look at the cost and those things. So what I recommend to owner is that if they are interested in adaptive reuse thing, then spend your money on the foundation because it costs a lot to retrofit the foundation or to upgrade the foundation system. So spend your money on the foundation, but for the other structure, let's leave it the way it is. And when you decide come back and you know at that time what the live load and what the structure uses is, we could, if you have to step in some of the beam, retrofit some of the beam, some of the column, that will still save owner money than spend all the money now. And they may never use that one. Thank you. Perfect. All right. So moving on here, if you guys have any questions, you can see on the slides here, you can get a hold of both the presenters. You can also get a hold of technical inquiries at post-tensioning. And so if you have questions for PTI, just go there and it gets forwarded to the appropriate folks once you ask that question there. So you got two ways of asking questions, both presenters and us at PTI as a whole. So I'm looking ahead to the next three months of webinars that we're going to be doing. February, we're going to go into the evaluation of existing post-tension concrete structures. So we did a webinar back in early 2024 on existing post-tension structures. Got a lot of great feedback on that repair, retrofits. There's a lot of conversations requests that we receive at PTI around that. So February 12th, we're going to give a webinar on that. Then March 12th, we're going to do one on the new ACI PTI 320-25 joint code. So this is a new joint code between ACI and PTI. And we'll be having some of the folks from our design team, the design committee DC-20 will be presenting on that as they're very active in both ACI and PTI on that front. And then I had mentioned at the beginning of the last two webinars we did were slab on ground construction. And we've gotten a lot of great feedback from there, a lot of requests for more of them. So we have several scheduled for 2025. And so we're going to go to slab on ground construction and maintenance. The one we did two months ago was on the geotech side. Then we did one more on the structure side and the design of it. And now we're going to go to the construction maintenance. So that's the look ahead to the next three months there. As I mentioned at the beginning of the webinar, these are the same exact time every single month. So it's always that second Wednesday of the month of the month. And it's always at 10 o'clock Pacific time, one o'clock Eastern time, or somewhere between wherever you reside in the US there. So with that, we'd like to thank you guys for joining. We hope you have a wonderful day. We'll give you a couple minutes back and we will see you all next month. Have a good one. Bye.

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