Why Some Roads Are Made of Styrofoam

What do you do when soil is too heavy for the job? Use lightweight backfill!
Over the years, engineers have come up with a lot of creative ways to mitigate the settlement of heavy stuff on soft soils, but one of those solutions seems so simple that it’s almost unbelievable: just make embankments less heavy.
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[@PracticalEngineeringChannel]

🌉Have you ever hit a bump going over a bridge? 🥑Convert dinner from a chore to a fun night in with HelloFresh: Use code PRACTICAL65 at bit.ly/3D5GV8S

[@Jablicek]

Have we ever hit a bump going over a bridge? The first thing that comes to mind is that "ka-thunk" sound from both sets of tyres. Of course we have :)

[@networkedperson]

the background music in your video isn't loud and annoying enough.

[@terryanderson4366]

Truck driver joke for bridges in Louisiana was we need a step ladder to get on and off.

[@stevenjlovelace]

There's a bridge in Dallas (southbound Greenville Avenue over the DART Blue Line) where there's a significant bump at the end of the bridge. They've patched it at least twice, but it's obvious that the ground just keeps settling.

[@networkedperson]

@@stevenjlovelace a jackable ramp, 3 meters long, would solve the problem. Just send someone out to jack it up every 6 months.

[@unvergebeneid]

"A catastrophic loss of function" is just the most hilarious and accurate engineer-speak for "the building collapses on you."

[@genericscottishchannel1603]

significant emotional event

[@racistman928]

Unfortunate unintended obsolescence

[@Blox117]

A catastrophic loss of function also applies to condoms.

[@NikolayAkimov]

RUD in rockets - Rapid Unscheduled Disassembly

[@christianheichel]

"Is there a doctor in the building?" "Unfortunately, yes."

[@burke615]

"Soil is heavy. They teach us that in college!" is the funniest thing I've heard today. Also, I learned that those "abandoned" highway construction sites that I have been complaining about for literally decades may not in fact be due to scheduling problems or lack of funding. They were probably just waiting out the settlement period. It's stuff like this that is why I love this channel.

[@johnmicheal3547]

In short you are just guessing. People need to be inform why they are having to suffer. Imo gov also use that to milk more fund out of the poor suffering and be tortured tax payer while at the same time the allocated fund direct elsewhere.

[@x--.]

@@johnmicheal3547 Sounds spot on. Been driving past a bridge project the past two weeks, serious inconvenience with the shutdowns, and not seen a single worker any time we've gone by. Not one, not once, just barriers and two parked tractors.

[@Turalcar]

What about "Guideline and Recommended Standard for Geofoam Applications in Highway Embankments for lightwight bedtime reading"

[@KainYusanagi]

@@x--. Delayed shipping of needed materials due to the logistics jam the world is STILL experiencing thanks to Covid can mean something meant to be done now is done three weeks from now, or even later.

[@djinn666]

The problem there is one of communication. People should be told why the construction site is inactive.

[@antidexterous3902]

Thanks for making this. Living in Seattle as a member of a family of civil engineers, I was pointing out the use of styrofoam in the construction around the viaduct southern entrance. My mechanical engineer colleagues refused to accept that the styrofoam was used for structure, insisting that it must be temporary packaging waste! I'll happily share this video with them.

[@randomname4726]

That will be so satisfying.

[@gunner4544]

Just remember, civils build targets… mechanicals build weapons… mic drop.

[@mikewatson4644]

About 60 years ago, I visited Seattle. I was surprised to see empty lots with soil piled up sometimes up to 10' high. When I asked, I was told that they did this to compact the soil. It might take 2 - 3 years to compact the soil, then they hauled the dirt someplace else and started a building project. A learning experience for a farm boy from Wyoming.

[@liamhodgson]

A family of civil engineers and a family of beavers are basically the same thing

[@argenteus8314]

@@gunner4544 You say that like building weapons is a good thing. When in reality, it just reinforces existing power structures and increases the odds of us all dying. We've had weapons capable of causing human extinction for nearly a century now, how can anyone still think we need to invent even better weapons?

[@alexpyattaev]

In Scandinavia it is common to use styrofoam as foundation material for buildings. The thermal disconnect is highly desirable when its -20 C outside, and it provides a very good stability when ground changes shape due to freezing water. Maybe an interesting subject for a video?

[@zapfanzapfan]

If done correctly the ground under the house does not freeze, in fact sometimes extra insulation is placed in the ground around the corners of the foundation to prevent freezing of the ground underneath the corner which could damage the house.

[@madistamela5975]

@@zapfanzapfanWow. Really? Profound statements and deep Knowledge in the comments:)

[@zapfanzapfan]

@@madistamela5975 If you have a poorly insulated foundation the house keeps the ground warm enough to not cause a problem by freezing but now with very well insulated foundations for passive houses it has become more of a concern. I was surprised the first time I saw it before I understood why.

[@MadSwede87]

I heard that a problem with this method is that animals can get into it and start digging it out, then it can be a big problem

[@AllYourBaseAreBelongToU5]

I wonder if it this is how the floating islands were made along Norway’s coast.

[@marcberm]

I think a major takeaway that transcends industries and disciplines, is the fact that the least expensive suitable material does not always result in the net least expensive finished product.

[@macmedic892]

Cheap goods aren’t good, good goods aren’t cheap. Well, usually.

[@KainYusanagi]

On the other hand, what's cheap now might not be so cheap later, if repairs need to be done because of improper material use.

[@seth094978]

It reminds me of how much extra time I spend at work dealing with the inconsistent and sloppily made recycled a36 steel versus how smoothly it always goes when I get to work with nice well made grades like 1144 or 4140.

[@AllYourBaseAreBelongToU5]

In the computer networking field, we learn this the hard way. Equipment that costs less upfront often will cost more with reduced uptime and increased labor costs in troubleshooting or consulting fees. Buy reliable products out of the gate and save yourself a lot of hassle.

[@marcberm]

@@AllYourBaseAreBelongToU5 I see it all the time too! Companies implement the expensive, complex software and cheap out on the servers to run it.

[@cyclonicleo]

I worked for an EPS manufacturer many years ago and one of their contracted projects was scrap EPS blocks to go into the middle wall and other sections of a dual tunnel roadway. The grade was usually a SL or L grade (Super Light or Light) EPS block, up to 5 metres long, by 600mm by 1.2m. For its size, they're very light. Saved the joint venture construction partners millions in fill and related costs, plus gave the EPS company plenty of work besides making sheets insulation and lobster boxes.

[@johndododoe1411]

I didn't know standard block forming machines could do 5m blocks, I thought they were standardized at 2.5m industry wide. Obviously making a double size machine is technically trivial, just not what can be easily ordered and shipped from a major supplier of EPS equipment.

[@Ixidora]

As a native Mainer I thank you on behalf of our lobster industry

[@matsv201]

Do you have a number on that or is that a European thing? Here I can boy esp 60, 80, 100 and 120 and the number stands for I some unit (don't remeber what) pressure it can take.. pretty much forever. I calculated when I did my foundation and I needed less than 20 but that simply was not possible to buy. I know ir exist, I have seen it, but never seen it for sale.

[@FreekDijkstra]

Thanks for making this video. I live in the Netherlands, where large parts of the western part of the country are basically glorified swamp. In my new neighbourhood, the decline is 2.5 to 4 centimeters a years, and have been declining at this rate for about 30 years now. The locals often refer to the peat ground as "thick water". All houses are build on poles, that reach a layer of sand 7-10 meter deep, and are stable. However, gardens and roads are not. Over time, in particular the roads have subsided (not really settled, as it is still declining) and the common solution was just to add another layer of asphalt on top of the parts that settled too much. Of course, that added a lot to the weight, so it settled even further. They found that by now some parts of the asphalt were 1.5 meter thick. After some heavy rain they decided to tackle this and for the whole village, street-by-street, and replace the heavy roads with low-weight material that basically floats on top of the thick water (also known as "ground"). It's a 10-year project, and interesting to see. Other solutions were tried as well, like excavating the borders of a neighbourhoud up till the sand-layer 7 meter deep, and replacing it with clay. This basically turned the watery ground into a bath tub: all the peat (thick water) in the middle would be contained by sand underneath and impermeable clay on the sides. In theory, this should stop the decline of the ground. In practice, it failed. It just keeps declining about 3 centimeters every year.

[@alexanderpas]

A better solution is to treat the large roads the same way as the houses, by building them on concrete plates supported by poles, with an asphalt top layer.

[@davida3283]

I admire the Dutch engineering, nevertheless, you will need to make everything float because the sea will rise

[@sachadee.6104]

Hoi Freek Dijkstra. Welk dorp is het? Interesting comment. I think I've seen a Dutch documentary about that but I forgot where. I would like to see if I can find that again. Maybe you can mention where your example happened and when ? Bedankt !

[@joshyoung1440]

Well yeah about the bathtub idea failing! The clay may be impermeable but it's still perfectly deformable! It'll stretch like sweatpants on thanksgiving!

[@joshyoung1440]

​@@alexanderpas and where do you get the surety to declare that your idea is better? I'm assuming you're a road engineer, right?

[@Grunttamer]

Two really great lines in this: “catastrophic loss of function”, and “soil is heavy, they teach us that in college”

[@osukaa71304]

As a Lab Technician for ENGEO I would like to thank you for all your videos. They serve as training aides for our interns, and help us explain what we do and why we do certain testing in a simple and entertaining way. We can show them your videos and then what we use in our lab setting. Keep up the great work.

[@Tara_Li]

Have ya'll considered sending him a bit of money?

[@logank444]

Gotta love modern KZbin

[@madistamela5975]

But this is superficial knowhow. Barely scratches the surface. Maybe 2 pages out of a 600 page book.

[@Tara_Li]

@@madistamela5975 You do realize getting students past the first two pages of the book is often the hardest part? Besides, you're wrong - this is an overview of a section. Combined with other videos from this channel, they form a fairly comprehensive overview of the field. Then you have the students digging in, often with stills captured to point out specific things. And then there's the additional bits of non-textbook knowledge from experience that pops up - you do realize Grady is actually a working engineer, right?

[@madistamela5975]

@@Tara_Li Introduction/overview of course. That is it. As with many topics on KZbin. Be it history, cosmology or quantum mechanics-sounds interesting and profound for general audience. Not so after 10y actually in the field like in my case.

[@fantabuloussnuffaluffagus]

One of our local bridges has an approach underpinned with Styrofoam, it wasn't protected properly and rats got in there and made enough tunnels that the surface of the approach started to subside.

[@Maleko48]

Can confirm: I worked as an Operating Engineer and placed many thousands of yards of cellular concrete all over the country and our primary work was on bridge embankments and abutments, especially in the Bay Area of California. We also did many abandoned pipe fills using it for pressure grouting and some interesting annular fill projects too.

[@chazzard3746]

I love how you demonstrated EPS' weakness to fuel spills by essentially making Napalm.

[@goodbyemr.anderson5065]

Here in Canada when a section of the trans canada highway was being upgraded from two lanes to four lanes there was a section of about 2 km crossing a swamp, the swamp had muskegs that were over 90 feet deep, and the engineers used drills and bored into the swamp using tubes to collect the water, and diverting it into pumping stations, then the whole thing was built up with geofoam. All of the drilling and piping techniques are covered on this channel. Thanks for the great content:)

[@theironrhino110]

Is that the upgrades around Parry Sound?

[@goodbyemr.anderson5065]

@@theironrhino110 No on highway 11 just south of sundridge.

[@zwojack7285]

just one more lane, bro

[@goodbyemr.anderson5065]

@@zwojack7285 math is a tough on for you isn't it.

[@cezarcatalin1406]

@@goodbyemr.anderson5065 Just two more lanes bro, it will solve traffic this time bro.

[@NickBiancalana]

"Soil is heavy! They teach us that in college." -- This is the type of engineering humor I expect here 😆

[@SafeTrucking]

About 25 years ago, I was part of a geotech team tendering for a second bridge across the Swan River in Perth, Western Australia. The ground was very soft alluvium, and the embankment needed to be quite high. We proposed a stabilised soil fill over foam-core solution, but were unsuccessful - the Main Roads Department were very conservative (and still are), and went for a conventional (and much more expensive) pile-supported solution. Nice vid, thanks.

[@user-bu2mn8do6v]

Here in the Netherlands we need a combination of eps backfill and pile supported retaining walls after the ground was compacted by adding 3 meters sand on top(with vertical drains to 15m below surface) and let it settle for a year.

[@SafeTrucking]

@@user-bu2mn8do6v The Netherlands virtually invented wick drains and preloading! I had no idea you used EPS, but it makes perfect sense.

[@matsv201]

There was a motor-road built in sweden and Norway in the 1960s. During the time from 1960 untill 2010 the road was upgraded to a full highway. The main part between Malmö and Göteborg in sweden was the first long part that was totaly finished some time mid/late 90s. The last section to be built was a fairly large Marsh like area. The old road went far around it, but when it was upgraded it was just not an option. The last bit built had to go right throw the swamp land. There was rock under, so it could be piled, but eventually they made it to a testbed for the first fully esp supported road. And to this day, almost 30 years later, it's one of the most even roads.

[@SafeTrucking]

@@matsv201 Our Principal was inspired by the use of EPF in the Nordic countries and I believe in some of the far northern permafrost zones in developing this proposal. His background was in London, as well as in the Gulf of Arabia, and he had an encyclopaedic knowledge of working with both soft estuarine sediments, such as London clays, and the calcareous, often weakly cemented sediments found in the Gulf and across much of WA, including around Perth and on the Northwest Shelf. I did a fair amount of work offshore while I was working for him, primarily in pipeline route surveys, but also in marine construction. It was an interesting few years :).

[@armandgun]

Your content just keeps getting better and better! Big fan of EPS and using it more and more in my industry too.

[@jonslg240]

Can we all just pause for a second and reflect on the fact that we've never met a "light weight Phil?" 😁

[@cavemaneca]

I saw the EPS used for an overpass in my area. The road needed to go over a train track, and was in a developed area so the embankment had to be as thin as the road. As well, the area was partial wetlands so settling was likely a substantial concern. I had always thought it looked like styrofoam, interesting to find out that it was exactly what it looked like!

[@tylorburr7802]

Would you happen to live in SLC, Utah?

[@kindlin]

Styrofoam can have 50-100 psi compression strengths, in inherently spreadsouts out load well if it ever is overloaded, which seems unlikely given that most tires are more in the 30-50 psi range.

[@austinpearce8753]

Grady, I just finished reading your book and it was such a pleasure! It was fun to learn so much about the "boring" world, and you've imparted your curiosity on me as well. The illustrations are awesome.

[@User0000000000000004]

Does the book include a coupon code for Hello Fresh?

[@sangvoba4340]

ok

[@jomiar309]

That is what I live for--an easy-to-understand explanation of something I was only vaguely aware of. Grady, this is, hands down, one of my favorite youtube channels, and one that I share often with other people.

[@Thezxc568III]

Oh man I still remember when sand compaction video came out and introduced us to your channel., time really flies. Your content has been consistently amazing,, always looking forward to what you got for us. I'm not a civil engineer, but I just love learning from your channel.

[@BobWidlefish]

4:47 “Soil is heavy, they teach us that in college.” Haha! I love you!

[@FireFish5000]

03:35 As a NJB fan, I loved how you made sure to show 9 entirely different buildings/businesses being demolished or affected by the hypothetical bridge catering to car traffic.

[@Jehty21]

Especially after NJBs latest short that showed that bicyclists don't need traffic lights 🤣

[@Alfenium]

WE just needed a few more lanes bro. Gotta keep that traffic down, ya hear?!

[@FireFish5000]

And it only gets better when you realize how many homes/buisnessnes would have been demolished if this wasn't already a car dependent wasteland.

[@counterblue4275]

My grandfather started an EPS company back in the 70s (Plymouth Foam). I was so surprised to hear they had a contract with a major local construction project to fill in under the new roadways and embankments. This was so cool to see on here. Thanks as always for putting out the entertaining and educational content you do.

[@user-gk9lg5sp4y]

I'm a DOT certified inspector and I've worked on a road project where they built up a section of the roadway 3 lanes wide about 40' long and 15' high using styrofoam blocks because they didn't want the weight of the fill on top of some old but still live pipes under the roadway.

[@DonardoHenry]

As a person who is not an engineer, civil or otherwise, thank you for this video. I had a feeling that, this is why many projects around town take forever. I know this is just a primer, but still valuable information none the less.

[@PrograError]

well 90% of the work is just waiting ... just like in military... sometimes you are just waiting for that BRTTTTttt~~

[@johndododoe1411]

If only they would put up accurate signs of what we are waiting for as we are stuck staring at an abandoned work site blocking our daily commute. This would create a clear distinction between necessary inconvenience and incompetent mismanagement. For example, my commute has been seriously disrupted for years by a never explained decision to relocate every pipe and cable under a major road allegedly to prepare for an already controversial project on the surface. As a commuter I always felt that was an unnecessary step as they could probably have used pillars or horizontal load spreading to support the surface project while leaving most of the substructures unchanged.

[@johnmicheal3547]

A huge demand to speed things up.

[@louisvaught2495]

@@johndododoe1411 They do this very, very frequently. Public review of projects is mandated by a lot of places, people just overwhelmingly don't participate.

[@iantaakalla8180]

Then what would make public reviews simultaneously more popular and also not prone to trolling or the twisting of results to support a group? Because having accurate opinion and having lots of people act on it are unfortunately exact opposites.

[@seanmcdonnell1282]

Here in Pennsylvania most road construction drags on long enough that everything has fully settled by the time paving takes place lol. Love the videos! Thank you.

[@glennpearson9348]

Particularly, work on the PA Turnpike. That entire toll road is a hot mess.

[@johnsmith1474]

Not likely. But Penn. is Pittsburgh and Philly separated by Alabama.

[@jpe1]

@@johnsmith1474 Pennsylvania is ranked #5 in the country for “most hate groups” as defined by the SPLC. As someone who works in rural Pennsylvania, I can say there is good reason why some call it “Pennsyltucky”

[@Blazer02LS]

81 is never done....

[@CycFlame]

@@johnsmith1474 Hey now, Pittsburgh and Philly may be the two most famous shithole cities in PA, but you can't forget the capital, Harrisburg. As someone who lives very close to Harrisburg, it is continuously funny to hear this quite urban area referred to as "Pennsyltucky".

[@spunkkiller]

When you mentioned the buoyancy of EPS it reminded me of the Fraser valley floods in Canada 2 years ago where the ground water made the eps filling float and that broke the road on top of it.

[@santtilagmailcom]

I had a summer work on a road construction a few years back. The site was on a former seabed and wasn’t hard as rock. We used expanded clay as filler on embankments. There was a huge pool of it after the bridge. We used also tons of expanded clay concrete under the roads.

[@binky_bun]

I drove across northern Scotland last summer on the North Coast 500 route and stopped at a place called Moine house up on remote boggy moorland. There was a sign there which said that the original road crossing the moor which had only recently been replaced was built on top of bales of heather to stop it sinking into the peat. This road was hundreds of years old.

[@mrgreatauk]

There's a section of railway not far from me, near Manchester, crossing 'Chat Moss' which used a similar method, essentially building a big raft of Heather and branches, then covering it in rubble and building the railway on that. When they electrified the line a few years back I hear it was particularly 'interesting' designing the mast foundations and there was a lot of work monitoring relative movement between the masts and the railway!

[@rjmun580]

@@mrgreatauk George Stephenson was responsible for this work in 1829 and his locomotive Rocket would be chosen to operate on this Manchester to Liverpool line.

[@Speeder84XL]

Haha, awesome! I have seen those gigantic styrofoam blocks used as floating devices and have even lifted one (it feels unreal how lightweight it is, given how huge volume it has) and also seen them being used during construction of pipelines for district heating (in that case for heat insulation). But I could never think they would be strong enough to use for whole road embankments, haha. That's cool. The foamy structure and light weight also means very little material can be used to fill up a huge volume - which cuts down cost and environmental impact during manufacturing.

[@rytan4516]

In theory, one could argue that using styrofoam as backfill could count as carbon sequestration, reducing the environmental impact even more compared to using a similar volume of styrofoam for disposable cups and the like.

[@SeanBZA]

Those blocks, with a concrete top, and a mesh and gunite covering, are doing sterling service in the harbour as walk on moorings for the yacht mole, where they form the spine and walkways used to tie up the boats. there is a steel rim on the top used to provide the hard points to fix them together, and to carry the piping used to provide power and fresh water to the boats along it. easy to expand as needed, and as they float, they only need a chain to a bottom concrete block anchor, with slack to handle the tidal difference, to keep them in position, and a rolling gangplank to allow access at all tide heights. Been there for decades, and still going strong.

[@johndododoe1411]

I have only heard of their use in construction, but I have seen and handled slicing them into panels by pushing entire blocks through a frame of hot wires spaced according to desired plate thickness. This was between 1970 and 1990.

[@randomname4726]

The second half of your comment just repeated the video :P

[@michaelatkinson8434]

You have a true gift for taking complex issues and making them easy to understand.

[@Sydney_2011]

This is literally one of the best channels on KZbin. You’re such an amazing teacher, Grady. The way you clearly and concisely lay out the information in a very easy to understand manner is one of your biggest strengths, next to your knowledgeability. You make me look at the world differently and wonder what things are for, and why they’re designed that way. This leads me down many internet rabbit holes of information gathering, but they’re not as fun as your videos lol

[@Robingriffith1]

Here in the Netherlands we use it all the time. I've seen piles of 3m /10ft of sand just sink away, pushing the subsoil to the side. EPS (styrofoam) blocks prevent that.

[@startide]

We used foam sheets used for insulation to lay out our small swimming pool. It's notn the biggest load ever, but it's still 8 tons worth of water. The sheets can take the beating quite well. What they don't like is if the load is concentrated in one place (say a heel or a knee hitting the bottom of the pool). We have added "grass like" carpet in between to protect the foam further. It's been like this for a few years now, and it hold up quite well.

[@paulvild]

I would like to see that!

[@kensherwin4544]

Why ae high-heeled shoes being worn in the pool? 😁😁😁

[@startide]

@@paulvild there is a French KZbinr called "electron libre" that made an entire channel around intex pools, he has a bunch of videos on how he layed out the substrate and under coats for his pools. That's where we got the idea from. The grass carpet was an extra layer / final touch we added :p

[@paulvild]

Thank you, I don't speak French but I'll watch.

[@startide]

@@kensherwin4544 kids have pointy bones 😂

[@ryanclark7260]

I’m a 3rd year Civil undergrad and man. I love these videos so much! Winding down my day after dynamics and mechanics of materials to see the application and connections from the learning is awesome! Much love from Florida 🤘🏼🤘🏼📐🔩

[@alexia3552]

I'm so glad I found your channel, I never knew how much I loved civil engineering. It really is fascinating how the world we use works

[@Kevin-xw1eo]

I love engineering solutions like that. "This doesn't seem like it should work..... But it could"

[@robertgoff6479]

The thermal insulating properties of EPS foam have also been used in geothermal areas to reduce heat damage to the pavement. It was interesting watching construction of several hundred yards of roadway in Yellowstone National Park.

[@Jehty21]

@Ithecastic have you ever seen EPS foam get soft in the sun? Because I have seen Asphalt doing that.

[@ducatisti]

On our most recent Alaska trip we watched workers install EPS sheets as part of the Dalton Highway out to Prudhoe Bay. Waiting in yet another construction delay we enjoyed talking to a couple of workers who said the material not only helped by lowering the weight of the road surface, but also acted as insulation against blacktop and vehicle movement-created heat affecting the permafrost under the road.

[@sirkorbendallas]

Man I just love how passionate and informed you are on engineering processes and challenges.

[@Kiyoone]

love this channel. VERY educative and makes us think more about the vital infrastructure important to us all

[@glennpearson9348]

Educational?

[@User0000000000000004]

From your lapse in grammar, it sounds like you could use some Hello Fresh food. Order today!

[@Pizzafan622]

@@User0000000000000004 what?

[@tdumnxy]

I have been watching your channel since you were doing wood turning and Arduino projects. I got your book at Christmas and am enjoying it very much. Thanks for all the work you put into your videos. It is worthy of praise and recognition.

[@Rsenior1981]

A cool application of lightweight concrete is the concrete canoe competition a lot of civil engineering students compete in. As a mechanical engineer, it's really neat to see floating concrete!

[@Sheikrisvan1991]

Yeah

[@smorrow]

Seasteading too

[@danbert8]

I enjoyed making concrete mixes that floated for the ASCE concrete canoe competitions.

[@StephenGillie]

The replacement for Seattle's Viaduct was the tunnel. A huge section of Seattle's downtown used to be Beacon Hill, until settlers pushed the dirt down the hill to extend the city. This might be less-dense than traditional soil, wight might be part of why they used polystyrene. But parts of that area are below sea level. Would be interesting to get some more details beyond "it was used in the project".

[@chrismorris1304]

It's really inspiring to see your family (and cooking confidence lol) grow as your channel does! Keep up the great work, Grady!

[@dralexmclean]

As a retired mechanical engineer I absolutely LOVE following your channel. VERY interesting info presented in a fun way. Keep up the good work Grady

[@GooTube42]

I love your videos, always so informative. You make learning about roads fun!

[@User0000000000000004]

Always so Fresh. So Hello Fresh.

[@bobdobalina8910]

Thank you, I have often wondered why. I see a lot of styrofoam used at the on and off ramps of bridges. There is a particular place where I live where it's used in the road construction, going over a marshy area, two places in particular, and it's a noticeable drop after only a few years. They have replaced one of both sides of the short stretch a few times, since I have lived in the area, the most recent being last year after a once in 100 year flood eroded the sections of the highway significantly. I am curious as to why they would continue to replace these two sections the same way every few to several years, knowing that, in my opinion, it is not a permanent fix?

[@PracticalEngineeringChannel]

Hard to say for sure, but it could be that the permanent fix would take the road out of service for too long during construction.

[@CatCube2]

Could also be budgetary--for example, the permanent fix might be $1mm, while it's only $100k for the temporary fix. If you will never receive a $1mm appropriation for that road fix, well, you can't do the "correct" fix, so you just do the repairs you can afford. Especially if you can get sued if somebody gets hurt, so you can't wait to get the alignment back up to standards. Same way that somebody might be driving a beater car that eats repair dollars. They know full well that it would be cheaper overall to buy a good used car, but they also know they'll never have all the cash required to pay for the newer car in one place at one time, and they can't not go to work for a couple years to build up the bank account. So you spend the smaller repair money you actually have on hand. One other thing that can't be forgotten: it might be cheaper overall to just do the cheapo repairs. If the "permanent" fix is gobsmackingly expensive enough, you might want to just eat the ongoing costs as that will be less money. To continue with my toy example from the first paragraph: if the permanent fix is $10mm, you could do that "temporary" fix *100 times* before you add up to that permanent repair cost. If you will only be doing it every 5 years, it is better value for the taxpayer to just do the temporary fixes. (This assumes that you're not having the road closed unduly long--as Grady points out, that has a cost of its own.) The first rule of civil engineering is "Every Hole Is An Adventure." You don't *really* know what's involved in something until you actually start construction. In my own field (structural) you might have as-builts that purport to show where the reinforcement is in concrete, but prepare to be surprised once workers start drilling in anchors. When digging a foundation, most of the information comes from boreholes on fairly wide spacing, and they can miss entire geologic features between the holes that then impacts your design. You start digging in a marshy area, you don't really know what's down there, and a "permanent" fix in those conditions might be very, very expensive.

[@professorofdeath7965]

I'm always impressed with the quality of content you and your team makes Grady! Keep up the great work

[@DrWeird]

I saw this process being put to use recently on the I75 rebuild through Metro Detroit, watching this jogged my memory of driving the the office and on the northbound lanes seeing giant blocks of foam being used to build an on ramp between 2 large concrete retaining walls going from the service drive at ground level to the subgrade roadway below.

[@ron6625]

The issue with the lightweight fill used in near waterways, is that it will also saturate and hold water quite a bit longer. Then you have to deal with more erosion. Especially when you're dealing with sheet walls and reinforced anchors. There's no such thing as free fill. Usually cuts and fills are equalized to reduce costs, but by doing so, you often create scenarios where you're placing things at less than ideal elevations. When I hear there's excess fill available near a waterway, either they increased the size of the water frontage, or they're under building the surrounding infrastructure to make things flatter or more esthetically pleasing. Not always the greatest idea in terms of longevity. Sometimes free fill comes from not actually hitting compaction specifications (but saying they did). Fantastic video as always. I'm an industrial/construction surveyor, and I'd love to see Grady's (a perfect name for a civil engineer btw) take on soils load testing. I've seen some questionable approaches to it in my travels. -Specifically field measurements and different techniques- Eg: Plate load testing on compacted fill before raft footings.

[@wojluk]

Hi Grady, thanks for nice video. I can confirm based on my own experience that this is working. I did time ago (as young engineer) the design of retaining wall (embedded structure, wall supported by laterally loaded piles). Because of mess in the project it turned out that wall has to be locally extended from 2m to 3.3m height (6.6ft - 10.8ft) during construction. To challenge that I thought that lateral force depend on backfill weight, so it needs to be replaced with lighter material. That was idea to use EPS blocks as most available light material. Then I did small research and discovered that similar solution was used in my country. That ensure me it is good idea and I implemented this into design. Despite structure is not impressive I am still very proud of that design. Greetings from Poland.

[@Suburp212]

I love that you have a compression measurement setup in your garage. Well done! Great video.

[@lanbao2010]

Chemical engineer here, but fascinated by the topics you cover here! Thank you for letting us into this mysterious world around us and making it simple to understand

[@cohutta]

This video made me think about arrestor beds installed at the end of some runways. I'd love to see a video on those and it was interesting to read how some of these same materials are used.

[@charleymiller5610]

I love your videos so much, and they’re one of the reasons I fell in love with civil engineering and why I’m studying it in college. Thank you for your hard work and incredible videos!

[@claykalmar8131]

I'm a Geotech Engineer who mostly works on PennDOT and PA Turnpike projects, and I approve of the definition of "a heavy pile of dirt" haha. We geotechs are often pretty chill because we spend lots of time playing in the dirt and working with that understanding that so much of what we do is working with nonhomogeneous materials, interpolating between borings limited by funding, and factoring for safety. I'm fairly young, so I haven't had the chance to work with lightweight fill material yet.

[@jud3s]

I remember watching the Apple Park construction timelapses years ago and seeing them build the hills out of what looked like blocks of foam - it’s good to finally understand why that was!

[@kingjames8283]

I know those huge Styrofoam blocks real well. In Nov 2012, I worked with Superior Construction delivering precast concrete wall panels to a new bridge over railroad tracks on Industrial Highway (now renamed Airport Road) in Gary Indiana. The bridge deck was steel/concrete, the approaches were done with six levels of these huge foam blocks topped with sand/asphalt. The wall panels we delivered contains the sidewalls to keep the foam blocks from shifting and to keep them from rising and/or floating away during periods of flooding. Important since this location is only 3/4 mile away from Lake Michigan. This project coincided with the expansion of the Gary Chicago Intl Airport. The local rail line that used to cross the north end of the airport property where the expansion occurred was moved further north to join the railroad east/west mainline, which also utilizes the new bridge, East Chicago Ave between Cline Ave and Industrial Hwy was removed. It was an impressive project which is highlighted on the airports north end on Google Earth. I took a few photos on the project and now 11-years later, it still stands. That was the first time in my 39 years in construction transportation being involved with a project that used Styrofoam as a base material. Besides the airport, the area is heavy industrial with heavy truck use and it has held up very well.

[@Private-GtngxNMBKvYzXyPq]

It’s always a good day when there’s a new edition of Practical Engineering. I wonder if lightweight materials might help absorb road noise and vibrations.

[@danielcomeau25]

I spend all day at work cutting cross sections of a roadway to add details of a FGA layer for load compensation, and I go home and see this video, very timely. Great as always

[@jonathanlanglois2742]

I only know of one bridge in my area where the ramp was built with high density styrofoam, and its also the one bridge where they had to rebuild the ramp. In my area, weight isn't a huge problem since you typically find bedrock just a few meters down at most. The bigger problem is usually drainage and soil movement due to frost during winter. Anything that is full of holes is a recipe for disaster. It accumulates water which causes massive problems as soon as frost takes hold.

[@gloomyblackfur399]

I wish you had discussed the environmental downsides of Styrofoam. It's probably the worst of all plastics. I am curious if roadway engineers have mitigated any of those issues or if they just ignore them for the short term benefit of "completing the project quickly".

[@adrien5568]

I fully agree!

[@curlyhairdudeify]

We don't Greta Thunberg.

[@Foiliagegaming]

I work in IT. But I love engineering and originally went to school for it but was to young and dumb to put the effort into it then. I would like to get a degree into some kind of engineering in the future. Great content!

[@williamhawley6579]

This is crazy timing cuz I JUST learned about concrete lifting yesterday, saw some cool Timelapse’s from a company’s channel here on KZbin. They were using polyurethane foam type stuff to fill voids and lift entire stretches of sidewalk, porches, road, whatever. Super neat

[@qzwx4205]

ive seen big cubes of styrofoam under a road during construction and thought it had to do with frost management, but now that ive seen your video i remember that it was on some part of an embankment for a highway overpass... gotta learn something every day!

[@barefootalien]

Fascinating! I had no idea this was a thing! I have a question, though, Grady... One of the problems with EPS is that it's notoriously unrecyclable and non-bio-degradable. Obviously that's part of _why_ it makes a good lightweight backfill material, but I can't help but notice that they're freshly cast blocks made specifically for this purpose. Could shredded post-consumer/post-industrial styrofoam be used instead, like an aggregate? It'd be denser and a little heavier than the blocks, and weaker, but it would also be basically free (possibly even negative cost). Possibly a good compromise between the engineered blocks and the foamed/expanded aggregates? Or would it be too springy? I'm picturing something kind of like sandbags filled with shredded EPS, so there's some interlocking and added strength, a little like the reinforced aggregate from your early video.

[@SeanBZA]

Probably can be as simple as shredded EPS packed into polyester bags, like gabions are, with the bags then placed in position, and then filled with a thin slurry of foamcrete to set the bag into position, locking the EPS into position. Then the exterior gets a gunite layer applied to it, and a mesh reinforcement in between the 2 spray coats, and then the final fill soil is added to it. The bags will hold up quite well, and are also a thing that has to be disposed of, leading to them being able to come pre filled, but very light, to the site, and needing only a telehandler to position them, then use the existing concrete pump you have there to fill them, with your concrete batching plant making the light slurry on site easy enough, using shredded foam that has been coated to allow concrete to adhere to it well, and thus not separate during cure. Coating is just tumble in a mixer while spraying cheap acrylic paint onto it, then tumble till they are more or less dry, and add the cement and water.

[@KainYusanagi]

Styrofoam can be and is melted down and repurposed. Just because these blocks are freshly cast doesn't mean that the original material is freshly procured. Shredded material in bags also wouldn't be very stable.

[@barefootalien]

@@KainYusanagi Where are you getting that? My understanding is that while it is _possible_ to recycle styrofoam, it's prohibitively expensive, because you can't just melt it down thermally; it takes solvents and a multi-stage chemical process. Plastic recycling in general isn't anything like as successful and common as people tend to be lead to believe, and my understanding is that styrofoam is one of the _least_ recycled, at less than 2%.

[@DerpyPenguin4747]

@@barefootalien EPS styro is actually pretty simple to recycle as far as styro materials go. Other forms of styro such as XPS are more difficult if not impossible to recycle.

[@mark77193]

@@DerpyPenguin4747 Expol, who manufacture EPS products in my area, recycle offcuts and waste EPS by shredding it and casting back into blocks for this sort of use. Just needs the right combination of heat and pressure to make all the bits stick back together.

[@J.C...]

We just had a landslide here from all the rain. It was on the hill of a circle off-ramp from I-220 in NW LA, next door to you. A chunk of land about 70yds wide x 40 yds tall slid down about 10 feet!

[@J.C...]

And it's not the first time it's happened at this off-ramp from I-220. That's the craziest part. Pretty sure it was the same exact spot. If you want to pull it up in G. Maps, it's i-220 at N. Market St in Shreveport LA. It has a figure 8 design and the ramp getting on 220 east is where it happened I believe. You drive right next to part of the 8 as you get on 220 and that's where it slid. It was pretty wild to see.

[@DougGrinbergs]

10:55 EPS Expanded Polystyrene foam 13:16 used in Seattle Alaskan Way viaduct replacement. (Here in the Boulder area, geofoam blocks were used to repair 2019 US36 sinkhole at 104th in Westminster)

[@MolonyProductions]

Thank you so much for making this. My Father is an engineer and he mentioned this to me in passing a couple of months ago.

[@GoCoyote]

We had a section of a 4 lane divided highway near us that just kept sliding down the mountain. After decades of lane closures and repairs, they finally just removed the soil/clay in that section and replaced it with Styrofoam blocks. One would never know that you are driving over thousands of giant Styrofoam blocks. I marvel at how stable the area is now, while wondering how often I am driving over Styrofoam on other roads.

[@Phootaba]

I've seen in Sweden that our bridges and overpasses, that the roadway is not rigid connected, but rather supported by wheels on the support column. I have my ideas on why, but it would be cool with a video explanation 😊

[@PrograError]

ain't that just expansion joints?

[@Phootaba]

@@PrograError yeah most likely, but don't ruin the video fun 😉

[@jasonreed7522]

That is primarily to allow thermal expansion. If a 100m bridge expands by 5% between summer and winter that is a 5m expansion/shinkage that needs to be accomodated. Usually 1 end is "pinned" so that it can't move in any axis, and the other has rollers to allow it to move in 1 axis but trapping it on the other 2 (technically its its held in place vertically by gravity but that force goes through the roller and pins). The end with the rollers also shoulf have some sort of interlocking teeth, being more noticeable the larger the expansion joint needs to be. On a small bridge its likely to only be a couple cm or in big, but on a large bridge they could be several meters or yards long. Note: the numbers for my hypothetical 100m bridge are probably very unrealistic but were chosen to be easy to do mental math with.

[@Jehty21]

@@Phootaba he already made a video about that. ( -IIRC it was a short- ) Edit: not a short. The video is called "Why bridges move..."

[@strings1984]

I can't thank you enough for these videos. As a kid who grew up reading how things are made, making my own erector sets and functioning tractors and cranes out of Legos and toy car motors , and loves all things engineering... Thank you.

[@miserepoignee9594]

I appreciate these videos that help me learn more about the created world around me!

[@User0000000000000004]

Silly you. The real reason for these videos is to tech you about ordering meal kits from Hello Fresh. It's groceries with more steps but hey, it's Internet! Buy yours today!

[@JohnnyMcMenamin]

I never knew this fact… Thanks for another lesson.

[@ChiefNonsense]

Watched these blocks being placed on a project near work and had no idea what the purpose was. I had (incorrectly) guessed maybe it would aid in digging back down in a temporary setup. This now makes perfect sense! They were filling about 35 feet over a newly installed drainage system.

[@Torren1000]

they used this on one of the roads near me. during the flooding in the fraser valley the other year it actually caused the road to lift up almost six feet in one place.

[@yt650]

About 15 years ago my son bought a house that at that time was 25 years old. While we were putting a trench in the yard to handle some surface water, we discovered that the builder or workers who built the house, buried some of the foam board that was excess to their needs. I was surprised the foam board was in perfect condition and once washed off perfectly usable again.

[@kurtlindner]

This is hilarious. I see future archaeologists on your sons property, the area cordoned off with markers and string, all of them hunched over a small white corner protruding form the soil, and slowly dusting away dirt with a tiny brush. 😄

[@WhenDoesTheVideoActuallyStart]

I mean, it's plastic. I'd be surprised if anything had happened to it.

[@yt650]

@@WhenDoesTheVideoActuallyStart I agree with you however, there is one more part of this perhaps you didn’t think about. Chances are the builder or the workers thought it would decompose and/or they could hide it in the soil graded around the house. The same thing applied to people doing excavation work and trenching for us, they wanted to throw their soda cans and foam cups in the ditch and cover them up out of sheer laziness, and never considered recycling.

[@crystalsoulslayer]

I'm much more intrigued by the floating concrete than the styrofoam, to be honest. It's in that category of "ordinary thing given counterintuitive properties," like making clear wood or boiling water at below-freezing temperatures in a vacuum. Weird materials are fun in general. Carbon nanotubes! Aerogel! The mysterious sticky stuff my nieces leave on surfaces they should have no reason to touch!

[@maxwang956]

I was expecting it once he mentioned foamed glass since that's basically man-made pumice.

[@gasengineguy]

We have multiple of these where I live, after a few failures they switched to these and has worked great

[@TBrady]

I have been on alot of job sites and almost all of them use conventional dirt fill. First time I ever saw foam used was at the sales force tower in San Francisco and as an electrician, I couldn't be more happy to work with it over dirt.

[@sachadee.6104]

This was very interesting. I've seen the building of the Montréal, Quebec, Canada A30-bypass and that involved LARGE overpasses and new highway lanes on somewhat swampy land. I noticed that large blocks and sheets of styrofoam where on site and always wondered what exactly that was used for.

[@dedogster]

Same thing here in Ottawa! Now I know!

[@mashrien]

12:43 Ah yes, styrofoam (packing peanuts work better) dissolved into gasoline (or kerosene) .. also known as poor-man's napalm. Just keep dissolving foam into a container of fuel until no more will and you're left with a thick sludge that'll stick to just about anything and will burn for a VERY long time. (with a couple household additives, can even get it to burn for about 2 hours) it's also rather difficult to extinguish.

[@PrattTyler]

Grady's new book "Engineering in Plain Site" is a must have! Got it in the mail a few weeks ago and enjoying one section a day and learning tons. Fantastic!

[@birdsandthingsbeachandbush1064]

That was an interesting video like always.

[@jacksonbuckner5756]

Thank you for another wonderful video! Speaking of using styrofoam for thermal insulation, I work for a small mountain railway where we sometimes battle with frostheave (also a video idea? ;) ) We experimented with using styrofoam in the subgrade to prevent the ground from freezing. It worked well as insulation, but unfortunately the ballast stones have a knack of punch through the sheets under load!

[@ducatisti]

They also use it to protect the permafrost up in Alaska on the Dalton Highway for the same reason (and dang that road can create some epic frost heaves!). From what we could see they used some sort of fabric membrane between the aggregate and the foam to avoid the same problem.

[@matsv201]

It's worth saying that what people often call styrofoam, that is eps is not actually foam. It's made in a other way. Pollyuretan foam is actual foam. It's twice as good insulator but also twice as expensive (hence 4 times as expensive per volume) If you need a lot of insulation for a very low thickness that is what's needed. (Insulated water heaters and garage doors are often made of that. It's yellow and quite fragile.

[@wade2277]

The demolition of The King Dome clip you used was a real gut punch.

[@arednecksgarage]

I just want to say thank you for all the work that goes into your videos you do a wonderful job of teaching in a way that's educational and not boring and I think the best part is your hello fresh ad you really need to be paid more for those ads they're good

[@bobpieczarka4357]

I have hit those bumps a lot.

[@brett4264]

I remember, as a kid, back in the 70s, in Michigan, we'd find "lava rocks" on the ground that were light enough to float, but would be great as backfill. I'm not sure if they were natural because we had trains going thru a train yard that may have been carrying these rocks. Maybe there's a source of this "pumice"?

[@htopherollem649]

if you check out Geology Hub's KZbin channel he was just describing an underwater volcano that is erupting which is creating large amounts of pumice and the hazards posed to ships

[@Jon-gq7wt]

I love you Man! Best engineering vids, keep them coming! Thank you!

[@sarcasmo57]

"Soil is heavy. They teach us that in college." Love that.

[@3nertia]

As an aspiring "engineer" who lacks the social status or financial resources to be a real engineer, I just need to say ... THANK YOU! Thank you for the edification on a subject I otherwise wouldn't be able to get as much exposure to! I'm really grateful for this channel and other channels like it :)

[@liamhodgson]

If you would like to work in engineering a lot of engineering consultants will have “project specialist” roles that do not require the same credentials but would allow for on the job training that would allow you to do what the engineers do. Enough on the job training and years of experience can replace the degree requirement to start an engineering career

[@3nertia]

@@liamhodgson Sadly that is not a possibility for me but I appreciate the thought!

[@jasondashney]

@@liamhodgson "Enough on the job training and years of experience can replace the degree requirement to start an engineering career" If only all industries had this level of sensibility. I'm in construction safety and I am not allowed to train for a higher designation because I don't have a bachelors degree. I mean literally any 'ole degree would do. Floral management? Good enough. Instead, I have years and years of actual, real, on the job safety experience as a safety professional with a designation. It's just the next up designation I can't get. Ironic that I can't get it because instead of getting a random BA I was doing the actual safety thing, on site. I hate academia so very much. I can't spend full-time years just to get a piece of paper to say I can now study the thing I already do. I have a mortgage to pay.

[@aurorabyrd6104]

"Soil is heavy. They teach us that in college." - Grady 2023

[@patrickgallagher9069]

I'm a bridge engineer. I designed a foam fill approach ramp to a bridge in Seattle (south of the Alaskan Way Viaduct site. Foam fill was selected to reduce settlement during an earthquake. The soils were prone to liquefaction and this was one of many measures to limit the concerns.

[@SteveCirelli]

I love all your content, very educational. These structural videos always gets me wondering how I can get some of these materials or use these methods at home. Either with my driveway or house foundation. Or hire a company that uses these methods.

[@Kesh789]

It sounds like there's a much easier way to prevent any bumps. A hinged metal plate. Kind of like a lot of floating docks have, that way the ramp could settle entire feet and there would be bumps. Not that it would solve every problem lighter fill would have, but it would stop the bump outright, and I worry about the environmental effects of some of the methods mentioned here.

[@goodbyemr.anderson5065]

There is so many things wrong with this idea I don't even know where to begin. Please enlighten me on how a hinge would stop a bump hahahaha.

[@randommcranderson5155]

This wouldn't prevent a hump. The issue is the soil under the bridge embankment is settling over time as the new pressure from the embankment drives water and air out of it. All your plate will do is change the angle of the hump, and make a very hard surface for cars to hit as they hit the hump.

[@Jehty21]

@@goodbyemr.anderson5065 I think you misunderstood his idea. His idea is to attach a metal plate with a hinge on the bridge. The other side of the plate just lies on the embankment. So when the embankment settles the metal plate just becomes steeper. Of course the metal plate must be long enough that the gradient doesn't become to steep. And also heavy enough (or somehow fixed) so that it can't be picked up by wind. Other than that it seems like a viable option. An example where something similar to this is in use would be RoRo ferries.

[@Jehty21]

@@randommcranderson5155 no. The metal plate would bridge that hump. Like a ramp.

[@goodbyemr.anderson5065]

@@Jehty21 yeah but its still a bump. i understood full well what he meant. A bump or a ramp its still there and not what you want on a high speed highway.

[@frankmalenfant2828]

The biggest bumo near a highway bridge where I live is in a place where there is mostly styrofoam under the road... but it's also built just next to a peat moss field and this whole part of the highway has been quite at rollercoaster at first and they had to redo a big part of the fundation under it. I figure that kind of swamp is something very hard to build on.