I'm not an engineer but I took my fair share of engineering and physics classes in high school and college. Now I just binge UA-cam videos and make stuff. Your video was probably recommended because I've watched a ton of Practical Engineering's videos. Your simple explanation helped me understand why the retaining wall behind my house failed more clearly than any other resource I've looked at and I'll be able to make more informed choices when we replace it. Thanks!
Thank you so much Track (favorite comment so far, and yes I read them all😅). At some point there will be a part 2 to this video with more practical explanations about installation and drainage (possibly a bit more math/physics as well). You wouldn't believe how many failed walls I see around that (possibly) could have been avoided. I would say proper drainage and compacted good-quality backfill would have avoided more than 75% of the failures. (disclaimer these are gut feeling guesses, not based on adequate studies)
Lol the Google gods also brough me for the same reason but I do want to help my mate build his garage and that's going to require a decent retaining wallthanks for the info.
As a small business owner who has installed retaining walls and been reluctant to do it halfway, this video is both reassuring and very educational. I love content like this that is to the point and has the science provided to back it up. Thank you for the great video, please keep them coming!
As a geotechnical engineer who designs retaining walls, I found this video to be both well explained and accurate. May even share with the folks at the office...
I'm a civil engineer, but have primarily been working in aviation. This is a great refresher and a much more intuitive way of visualizing things than many of the ways I was taught, well done!
As a contractor here in pa, 4 things I find that contribute to retaining wall failures, drainage, frost jacking, poor backfill stock, wall material …chiefly using soils that are poor in draining, lack of aggregate to aid in drainage, and clay soils that could be useful if utilized properly…frost typically enters a design from its face and from the top, both have forcing action, and once that is set it cannot be removed, the wall usually suffers from displacement(s), rotation, or detachment…..wall design or selection of materials for the wall itself…
I would appreciate it if you continue the geotechnical series videos. There are many interesting topics to be presented like shallow/deep foundations, slope stability or even other retaining structures and how they work. Keep up the good job!!!
Very well presented. I’m a geotechnical engineer in Florida. I don’t see retaining wall failures often here. One that sticks out in my memory is a set of walls in a neighborhood that had trouble due to drainage problems. The poor drainage caused seepage and piping of the soils below the wall foundations. The loss of support to the foundations led to partial collapse of at least one of the walls. I don’t know too many details because it wasn’t one of my projects. It was in a neighborhood next to one of my projects, and I heard about it from the city engineer.
Thank you. I could have used this when I was in residential construction to explain to the owners the need for engineering in designing retaining walls.
If you enjoyed the video, consider writing a comment (positive or negative) 😊it doesn't cost anything, but it means the world to us🙏 You can also check out the other videos in this series below. Geotechnical Series Videos: 1. Understanding why soils fail ( ua-cam.com/video/5iROUI49Cjw/v-deo.html ) 2. Understanding the Soil Mechanics of Retaining Walls ( ua-cam.com/video/YtQ9ubNbytE/v-deo.html ) 3. Geotechnical Analysis of Foundations ( ua-cam.com/video/KgKW10iA_4w/v-deo.html ) 4. The Leading Cause of Foundation Failures ( ua-cam.com/video/qR5PrbDBCLw/v-deo.html )
As a civil engineering undergrad , your videos really helped a lot in visualising what I’m learning in classes , thanks a lot 😁 Keep up the good work 👍🏼👍🏼
Thank you for visualizing this complex Geotechnical concepts. Stability of soil is arguably the greatest challenge. In addition, one can intuitively summarise the four scenarios as follows: Case 1: compaction increases the shear strength of particles as they're pushed hard against another. For instance, if you press your knucles against each other and try sliding your fists, if you press hard as you do so there is increased resistance. Hence a relatively higher factor of safety (FS) is expected. Case 2: in addition to the already compacted soil, additional strength is added by the reinforcement. Therefore it makes sense that FS2 > FS1 Case 3: The key component here, is the presence of pore water pressure (pwp), simply put the presence of water decreases the shear strength of soil. This is because pwp refers to water within the soil voids which pushes against the grains, hence alluding to the fist-knucle anology, we can see why that is the case. In comparison to the two cases, we expect FS2>FS1>FS3. Case 4: Loose soil generally has higher shear strength than wet soil but lower than compacted soil, thus, we can deduce: FS2 >FS1 >FS3 >FS4 Thank you for these informative series, would absolutely love to see more visualizations, and other concepts such as 2D seepage.
Amazing summary, thank you so much! In hindsight, something like this should have been included at the end of the video to explain the 4 cases. Very well summarized!
Would love to see a drainage follow up. I’m a career carpenter and am fascinated how soils tests barely existed when I started and are now first order of pre-construction. For very good reasons.
This is very helpful! I actually have issues with a retaining wall which is holding my whole garden! This is so helpful to understanding things better as I try to get it fixed! Thanks!
Making such animated and upon it making our concept so clearly is very worth watching. Thanks you so much. The concepts are very basics. I like it so much.
You are correct Rai, there is so much more. We didn't talk much about cohesive soils and the undrained condition. Most likely there will be a follow up video to this but possibly after we go over foundations and slopes first.
Thank you very much for your excellent work. You make it easy to approach topics. You make problems visual and much more intuitive. In this case, you address an important subject for the general learning and mastery of civil engineering. I appreciate your work, as professional with 30 years of civil engineering on my backs, specialized in hydraulics, and working in civil works management in general, in Municipal Public Administration. I come to here because I appreciate the continuous study (throughout my life) of all kinds of topics globally related to my profession, such as calculus, materials, physics, chemistry and mathematics, about all specialties, including programming. And here I am, reflecting on soil mechanics, recording Prof. Manuel de Matos Fernandes, in the 80's of last century, at my Alma Mater, FEUP, Porto, Portugal.
I'm a concrete superintendent and we always compact the soil before laying any concrete slab and the same should apply to elevated soil, specially if behind a retaining wall , I'd build that wall thick like a Cantilever on the bottom to avoid tipping over and water drainage system like mentioned in the video
Great video! Would love to see more educational videos on the use of geosintherics, calculations, examples and casestudies of what they allow us to do now as opposed to what we had/used before.
In Canada these smaller, homeowner type retaining walls usually fail due to the absence of proper drainage, a problem in colder climates and freeze/thaw cycling. Dense soil is packed directly against the back of the retaining wall, preventing water from draining, and then freezing and expanding during colder months. Instead, these walls need an intermediary layer of clean gravel or rock to allow water to drain away from behind the wall.
Very well done! Thank you! Simple, educational and straight to the point. I’m studying for my CEG in California and am very excited to have found your videos. Please please post more! Suggestions- geotechnical sampling equipment, extensometers, inclinometers, e-logs, understanding lab testing, anything environmental. Thanks again!! Well done.
I love your videos, the way how you intuitively explain problems and adding animations, simulations and experiments. Now I can understrand the pure theory that they are trying to teach us in university. Go on :)
Very interesting and thought-provoking video. A question that's been intriguing me is whether sheet piling, when used as retaining walls, needs to be given a greater safety factor because of the impossibility of draining behind the wall. And whether, if used in fairly impervious clay soils, one ends up creating a pond, so reducing further the bearing capacity of the soils retained behind the sheet piling wall. If these surmises are correct, they would greatly reduce the usefulness of this method for stabilising a downslope on which dwellings are to be, or have already been built.
In my clay based soil areas. The Roads Dept is using stone filled gabions more. The stacked cages can be tied into the bank. The rock is permeable to rainfall. And is sourced locally. Its generally fast to install once old is removed and the base is considered wide enough. Crane truck to place galvanised steel cages. Dumper with rock. No concrete. No co2 gasses released. Usually fully finished under a week.
Thanks for the video. This is good for a designer like myself, who must make some decisions on approach, or preliminary assumptions, while working with structural engineers for the final design.
I live in Sweden, and there are many small 19th-century farm houses (huts by American standards: 3-room, built around a central chimney) built of logs, standing free of the ground on four or five enormous stones. I would love for you to bring these in as *comparisons* when talking about the various stresses concrete structures/foundations experience. Is wood a lot more flexible? Does the space underneath help? Or would the stones shift up and down on clay, leading to exactly the same problems?
Is this in relation to the expansive soils video or retaining walls? Maybe mistakenly it is written at the retaining walls video. In general if you can underpin the structure (even if it is stones) as long as those points are on stable ground and the structure is strong enough to span those points then it should be okay. Of course if the stones are on poor soil and say they start to experience large relative movements between them, then structural problems would follow. But as you said wood is more flexible than concrete (about 3 times more, depending on the wood species). If the floors and beams are made out of wood, then the structure would be able to tolerate higher differential movements before things start braking. I am not familiar with the geology of Sweden but expansive soils (or the mineral montmorillonite) are usually present in warmer climates. Of course there are exceptions and maybe Sweden is one of them but if it isn't then this problem would not be of concern.
@@TheEngineeringHub I thank you for your very long and kind answer! It's true, I was watching a string of your videos and my comments may have lagged. -- It varies in Sweden, of course; a lot of heavy silt/clay soil in some areas (old sea-bed), a lot of moss-covered granite in others. But wood is only 3x more flexible than concrete, eh? (In Sweden, it's usually fir, the older houses have the best quality.) Then with global warning and resultant longer, intense dry periods and sudden rainstorms, we should start getting problems with those small log houses, as well...
The 3x flexibility comment is a bit of a simplification. The Modulus of Elasticity (MoE) alone of concrete is about 30 GPa where wood ranges around 10 GPa (inversely proportional to flexibility). But MoE is not the only factor, the length of a member influences its bending flexibility the most. For example having - A 10 m steel rod of diam. 3 cm vs. - A 10 cm wood rod of diam 3 cm, The shorter wooden rod would be much stiffer and harder to bend even though wood is a more flexible material. The cross sectional dimensions further influence the flexibility in a non-linear fashion. All together, each structure would be a bit different but in general for members of equal size wood would be more flexible.
@@TheEngineeringHub Now THAT'S interesting. So real log cabins, with wood logs at 2+- meters (said logs resting on, not attached to, each other - except at the ends) would be flexible. I must say I was thinking in comparison to concrete, but then concrete is steel-rod-enforced, of course. THank you for tutoring the uninformed, it's fascinating!
7:25 Case 2 have longest friction surface, that`s why it have the largest safety factor. Longest friction surface provided by geogrids. Engeniging hub, geo-mechanical tasks are very hard and for my opinion are the most interesting for engeneers. Thank you!
I’m considering to do some alterations in my garden which involve shifting a retaining wall back by a meter or so, and to also place it against my single brick layer garage wall, but have no knowledge of what makes a retaining wall to be strong, so this video is a useful starter. I’ll dig out your first video as you suggest, and have a browse around your channel to increase my knowledge of this topic. Thanks for the video! P.S. I’m not sure if my plan is even a good idea as I don’t want my garage wall to collapse(!), so will also seek professional help if I decide to proceed
Love these videos and the EXCELLENT graphics! I'm a multi-family developer and need to crash course my way to soil, civil and structural engineering...would you please do a video on the most favorable to least favourable soils for low, mid and high rise residential construction??? And another very useful video would be "how to read a geotech report on a development site?!"...I think you would get a MILLION views on that!!! thank you!
For my work I come in contact with soil injection. This is new to me. As I live in The Netherlands, your videos help me to understand about the different soils and how they react. So these videos are very helpful for me. Thank you an keep up the good work 👍
I've always wondered why there is more geometry involved on the backside of retaining walls, ever since I saw what the flat walls of a canal lock look like on the back side facing the soil. They tend to be stepped so there is more pressure pushing down at the base of the wall. So I have to think there is some sort of shape or set of curves that would almost interlock with the soil it's trying to retain. I'm picturing the back side looking like a 3 dimensional jigsaw puzzle with longer pieces at the bottom. Or a jumble of tetrapod shapes facing the soil like you would with a seawall. All of course would be out of sight in the finished wall.
Would these principles apply to basements and other "boxed-in" structures as well? I'm in the midst of building a dug-down greenhouse, about 150cm/5ft deep.It's underground structure consists of a solid concrete footer with reinforced leca brickwork the rest of the way up to ground level. Could poor insufficient drainage lead to any structural problems down the line? Seeing as the longest side is only 5m/16ft in length, the depth of the footing and the quadratic shape of the structure being stronger than a free standing wall, I never gave much thought to the drainage. I'm now wondering if I may have overlooked it's importance
Please make a more detailed video on drainage systems for retaining walls. This information is very helpful in landscape construction projects im taking part in on a generally steep clay/silt rainforest climate area.
I'm working on a problem installation on the coast, where inside of a large rectangular concrete box is spent nuke fuel 53 feet from the edge of a bluff overlooking the bay and directly across from the bar of the bay. The top of the concrete box is 44 feet above sea level and the box is somewhere around 14 feet high, buried up to its lid that projects about a foot above ground. The soil is nothing more than sand and that sand bank used to extend further out into the bay, 1400 feet more, but has been eroded away at a rate of 30 feet a year until a large amount of large stones, (rip rap or revetment), was placed against the bluff. My complaint is this, with no pilings under that box or any other form of support, the full weight of the box, somewhere around 600 tons is resting on nothing but sand, and the sand under the box is bearing an immense amount of weight, so what's going to happen when a storm comes into the bay with large waves and starts breaking on the bluff. It'll denude that bluff face in no time leaving exposed sand and once those waves start to hit the bearing sands, they will liquify in a heartbeat, bringing down the soils above them right up to the face of the box which will allow the box to tip over, and if it does that, then we have a nuke disaster on our hands. I hope I was clear in my explanation, and if I was, does my reasoning make sense?
Most of the small town that I live in is on the Ohio River and is a sand plateau. My property has what was the end of a dragline set up for mining sand. I've lived here for about 25 years. The whole time I've tried to figure out how to solve br bracing for about a 20 degree off vertical thirty-foot drop that is within 10 feet of the neighboring property at the top. So, I'm very interested in your lecture on retaining walls. Thank you very much! This is in a residential neighborhood of mostly single-family homes.
This was really interesting, but left me wondering how ancient civilizations did retaining walls so well. We have been learning about the Inca and talked about the steps they did around their cities and within them. I know their are so many other civilizations that did steps too. How did they do them so well?
This is outstanding! Something left out, however, is longevity. Let’s say someone correctly crunches the numbers and builds a safe retaining wall, atop of which they construct a gazillion dollar structure that should last a few hundred years. Will the retaining wall last that long without re-shoring?
I have a question. I'm adding a low footer bed to a front drive that will only be about 18-24 inches. how high do I need to start worrying about pressure of the soil against the low wall. I'll be using cement breeze blocks and the bottom half of the bed will be type 1 rubble. with standard soil on top. I need it to withstand someone standing on it. I was going to use standard cement to adhere the blocks together and was thinking of putting steel rods into the concrete floor that is the driveway at present. thank you.
Great Explaination regarding technical issues of retaining wall. One thing I want to add that it would be good if the types of retaining walls against different factors were also breifly explained. Keep it up.
Practical case for any expert viewer here : My 30 year old 4 meter high wall was pushed out some degrees after a rainy year . Now after a very dry year there is a gap of 6 cm visible right on the inside of the wall going pretty deep. Do we leave as is, do we fill up with gravel and improve drainage, do we try and bring the wall back with some anchors or add extra fibercoating to the outside. Any idea is welcome....(no guarantee I understand)
Hi, I have a slope and want to level it up with a retaining wall. Do I have to dig all the lawn on the slope? Or I can simply add back fill on the lawn?
Thankyou. I discovered your videos today and love them. The use of animations to communicate ideas is incredible. Would have made studying engineering a lot easier in understanding the concepts
Should the same approach be taken for a smaller retaining wall that is about 8 inches in height and 6 inches in width that will run along a black top driveway? Thank You
What about construction principles of “traditional” drystone retaining walls, i.e. base of wall as thick as wall is high, and leaned into the slope 2” for each foot of height?
I'd like to see a more in-depth presentation of Mohr's Circle. I'd also like to see an example design calculation. Parker's Reinforced Concrete Design is an excellent guide in this regard. As mentioned in other comments, expanding on each general example with design and load specifics would be wonderful to some of us.
You said any comment?? OK... Now we have an idea of (some of the) factors involved in building lasting retaining walls, how do we factor in shock loads like cannon fire on how the wall and soil performs? (Fortress walls, typically loose (compressed) fill with solid face). Passing vehicle or train loadings (assuming the retaining wall is for road or rail)? (Yes, I might have a wee bit of interest in historical stuff just because it is cool to know how things work).
I really liked this video and would like to hear more, especially regarding soil movement and foundations in sub-arctic regions. For some reason I love listening to enginerds and sometimes even understand a bit of it.
I'm not an engineer but I took my fair share of engineering and physics classes in high school and college. Now I just binge UA-cam videos and make stuff. Your video was probably recommended because I've watched a ton of Practical Engineering's videos. Your simple explanation helped me understand why the retaining wall behind my house failed more clearly than any other resource I've looked at and I'll be able to make more informed choices when we replace it. Thanks!
Thank you so much Track (favorite comment so far, and yes I read them all😅). At some point there will be a part 2 to this video with more practical explanations about installation and drainage (possibly a bit more math/physics as well). You wouldn't believe how many failed walls I see around that (possibly) could have been avoided. I would say proper drainage and compacted good-quality backfill would have avoided more than 75% of the failures. (disclaimer these are gut feeling guesses, not based on adequate studies)
💙🇹🇷💙 selama leykim 👍 emin ol 🐝
Lol the Google gods also brough me for the same reason but I do want to help my mate build his garage and that's going to require a decent retaining wallthanks for the info.
As a small business owner who has installed retaining walls and been reluctant to do it halfway, this video is both reassuring and very educational. I love content like this that is to the point and has the science provided to back it up. Thank you for the great video, please keep them coming!
Right. UA-cam videos are great when the author gets straight to the point without wasting our time trying to be cute.
I am a civil engineer and I want to applaud the quality of your video. I would call it simple and in good taste...
Hello, geotechnical engineer here. Can you please keep making these types of videos. This one was really useful for the younger staff. Thanks.
As a geotechnical engineer who designs retaining walls, I found this video to be both well explained and accurate. May even share with the folks at the office...
I'm a civil engineer, but have primarily been working in aviation. This is a great refresher and a much more intuitive way of visualizing things than many of the ways I was taught, well done!
Would like to see this continued into the design calculations and the assumptions behind each failure mode
They simply forgot to install the dead-man thing!!!
As a contractor here in pa, 4 things I find that contribute to retaining wall failures, drainage, frost jacking, poor backfill stock, wall material …chiefly using soils that are poor in draining, lack of aggregate to aid in drainage, and clay soils that could be useful if utilized properly…frost typically enters a design from its face and from the top, both have forcing action, and once that is set it cannot be removed, the wall usually suffers from displacement(s), rotation, or detachment…..wall design or selection of materials for the wall itself…
I would appreciate it if you continue the geotechnical series videos. There are many interesting topics to be presented like shallow/deep foundations, slope stability or even other retaining structures and how they work. Keep up the good job!!!
Hi Giorgos, a video on shallow foundations is in the making!
agreed!!
As an architect I can't thank you enough for your content.
I spent 50 years in electronic and electrical engineering. These videos are fascinating and full of interesting information. Thanks a lot. Colin UK 🇬🇧
Glad you enjoyed it!
Great Geotechnical series so far. Would love to see more
Very well presented. I’m a geotechnical engineer in Florida. I don’t see retaining wall failures often here. One that sticks out in my memory is a set of walls in a neighborhood that had trouble due to drainage problems. The poor drainage caused seepage and piping of the soils below the wall foundations. The loss of support to the foundations led to partial collapse of at least one of the walls.
I don’t know too many details because it wasn’t one of my projects. It was in a neighborhood next to one of my projects, and I heard about it from the city engineer.
Thank you. I could have used this when I was in residential construction to explain to the owners the need for engineering in designing retaining walls.
If you enjoyed the video, consider writing a comment (positive or negative) 😊it doesn't cost anything, but it means the world to us🙏 You can also check out the other videos in this series below.
Geotechnical Series Videos:
1. Understanding why soils fail ( ua-cam.com/video/5iROUI49Cjw/v-deo.html )
2. Understanding the Soil Mechanics of Retaining Walls ( ua-cam.com/video/YtQ9ubNbytE/v-deo.html )
3. Geotechnical Analysis of Foundations ( ua-cam.com/video/KgKW10iA_4w/v-deo.html )
4. The Leading Cause of Foundation Failures ( ua-cam.com/video/qR5PrbDBCLw/v-deo.html )
+ve
@@mayanksingh292 hahha love it!!🤣
Very informative, I enjoyed it. Thanks.
Excellent video, it would be great that you made a follow-up video.
Greetings from California.
Well Done Thank You !
I’ve been thinking about retaining walls lately. This video is a particularly fortuitous discovery.
Can't even think without someone listening these days, eh? 😅
So simple and sweet language of yours sir
I'm Indian, in the village living boy and studing diploma course in civil engineering.
Thanks sir
Wow superb. I can't believe this Geotechnical series. Even in my college I feel difficult to understand this concepts.
Thank you guys, comments like this make our efforts worthwhile 🙏
As a civil engineering undergrad , your videos really helped a lot in visualising what I’m learning in classes , thanks a lot 😁 Keep up the good work 👍🏼👍🏼
Thank you for visualizing this complex Geotechnical concepts. Stability of soil is arguably the greatest challenge.
In addition, one can intuitively summarise the four scenarios as follows:
Case 1: compaction increases the shear strength of particles as they're pushed hard against another. For instance, if you press your knucles against each other and try sliding your fists, if you press hard as you do so there is increased resistance. Hence a relatively higher factor of safety (FS) is expected.
Case 2: in addition to the already compacted soil, additional strength is added by the reinforcement. Therefore it makes sense that FS2 > FS1
Case 3: The key component here, is the presence of pore water pressure (pwp), simply put the presence of water decreases the shear strength of soil. This is because pwp refers to water within the soil voids which pushes against the grains, hence alluding to the fist-knucle anology, we can see why that is the case. In comparison to the two cases, we expect FS2>FS1>FS3.
Case 4: Loose soil generally has higher shear strength than wet soil but lower than compacted soil, thus, we can deduce: FS2 >FS1 >FS3 >FS4
Thank you for these informative series, would absolutely love to see more visualizations, and other concepts such as 2D seepage.
Amazing summary, thank you so much! In hindsight, something like this should have been included at the end of the video to explain the 4 cases. Very well summarized!
This is incredibly helpful to easily understand the mechanics and concept of geotechnical engineering. I hope there will be more of this! Thank you
Thank you Filip 🙏
Would love to see a drainage follow up.
I’m a career carpenter and am fascinated how soils tests barely existed when I started and are now first order of pre-construction. For very good reasons.
Building a landscape block patio DIY. This is immensely helpful.
This is very helpful! I actually have issues with a retaining wall which is holding my whole garden! This is so helpful to understanding things better as I try to get it fixed! Thanks!
Making such animated and upon it making our concept so clearly is very worth watching. Thanks you so much. The concepts are very basics. I like it so much.
Thank you so much for your continual support Muhammad, we really appreciate you 🙏
This presentation just touches the surface of a great topic. I want more! numbers even! geek out! 😎
You are correct Rai, there is so much more. We didn't talk much about cohesive soils and the undrained condition. Most likely there will be a follow up video to this but possibly after we go over foundations and slopes first.
Same. I really like the style you cover this material, and would love even more depth.
A perfectly understandable explanation for non-engineering types. Like me!
Thank you very much for your excellent work. You make it easy to approach topics. You make problems visual and much more intuitive. In this case, you address an important subject for the general learning and mastery of civil engineering. I appreciate your work, as professional with 30 years of civil engineering on my backs, specialized in hydraulics, and working in civil works management in general, in Municipal Public Administration. I come to here because I appreciate the continuous study (throughout my life) of all kinds of topics globally related to my profession, such as calculus, materials, physics, chemistry and mathematics, about all specialties, including programming. And here I am, reflecting on soil mechanics, recording Prof. Manuel de Matos Fernandes, in the 80's of last century, at my Alma Mater, FEUP, Porto, Portugal.
I'm a concrete superintendent and we always compact the soil before laying any concrete slab and the same should apply to elevated soil, specially if behind a retaining wall , I'd build that wall thick like a Cantilever on the bottom to avoid tipping over and water drainage system like mentioned in the video
This was very helpful. A dry stone wall has natural drainage, but this video made clear to me the value of compacted backfill. I am very grateful.
Great video! Would love to see more educational videos on the use of geosintherics, calculations, examples and casestudies of what they allow us to do now as opposed to what we had/used before.
Great suggestion! Thanks Aleksandrs
In Canada these smaller, homeowner type retaining walls usually fail due to the absence of proper drainage, a problem in colder climates and freeze/thaw cycling. Dense soil is packed directly against the back of the retaining wall, preventing water from draining, and then freezing and expanding during colder months. Instead, these walls need an intermediary layer of clean gravel or rock to allow water to drain away from behind the wall.
Looking forward to a “Part 2” of this video
Thank you. I would like to see a drainage solutions video.
Thanks for the feedback Susan, based on the comments so far a part 2 video on retaining walls has to happen! Thank you!
@@TheEngineeringHub me too!!!
Love your content. Please make a video on soil structure interaction.
Just ran into this channel. Keep up the absolutely amazing work!
Please keep making more videos, the more info the better.
Practical info from Knowledgeable Presenter!
Very well done! Thank you! Simple, educational and straight to the point. I’m studying for my CEG in California and am very excited to have found your videos. Please please post more! Suggestions- geotechnical sampling equipment, extensometers, inclinometers, e-logs, understanding lab testing, anything environmental. Thanks again!! Well done.
I love your videos, the way how you intuitively explain problems and adding animations, simulations and experiments. Now I can understrand the pure theory that they are trying to teach us in university. Go on :)
Glad you think so zoccat, welcome aboard!
There are only two kinds of retaining walls:
1) Retaining walls that have collapsed. And,
2) Retaining walls that will collapse.
Absolutely the best video out there. Good job brother, make a part 2 pls
Perfect explanation for regular people!
Very interesting and thought-provoking video. A question that's been intriguing me is whether sheet piling, when used as retaining walls, needs to be given a greater safety factor because of the impossibility of draining behind the wall. And whether, if used in fairly impervious clay soils, one ends up creating a pond, so reducing further the bearing capacity of the soils retained behind the sheet piling wall. If these surmises are correct, they would greatly reduce the usefulness of this method for stabilising a downslope on which dwellings are to be, or have already been built.
Incredibly explained the science behind RW.
Kindly go on with 2nd part as the topic is vast ..
In my clay based soil areas. The Roads Dept is using stone filled gabions more. The stacked cages can be tied into the bank. The rock is permeable to rainfall. And is sourced locally. Its generally fast to install once old is removed and the base is considered wide enough. Crane truck to place galvanised steel cages. Dumper with rock. No concrete. No co2 gasses released. Usually fully finished under a week.
0:09 _Which_ previous video? (Searching through a video list can be impractical.)
Here is the previous video in this series: ua-cam.com/video/5iROUI49Cjw/v-deo.html
Thanks for the video. This is good for a designer like myself, who must make some decisions on approach, or preliminary assumptions, while working with structural engineers for the final design.
I am a civil engineer and I just love you are videos on construction and the practical implementation of the topics we have studied in the college.❤
Im very glad to hear that Shub. Thank you for your nice words 🙏
@@TheEngineeringHub It is my pleasure to see this.
I live in Sweden, and there are many small 19th-century farm houses (huts by American standards: 3-room, built around a central chimney) built of logs, standing free of the ground on four or five enormous stones. I would love for you to bring these in as *comparisons* when talking about the various stresses concrete structures/foundations experience. Is wood a lot more flexible? Does the space underneath help? Or would the stones shift up and down on clay, leading to exactly the same problems?
Is this in relation to the expansive soils video or retaining walls? Maybe mistakenly it is written at the retaining walls video.
In general if you can underpin the structure (even if it is stones) as long as those points are on stable ground and the structure is strong enough to span those points then it should be okay. Of course if the stones are on poor soil and say they start to experience large relative movements between them, then structural problems would follow. But as you said wood is more flexible than concrete (about 3 times more, depending on the wood species). If the floors and beams are made out of wood, then the structure would be able to tolerate higher differential movements before things start braking.
I am not familiar with the geology of Sweden but expansive soils (or the mineral montmorillonite) are usually present in warmer climates. Of course there are exceptions and maybe Sweden is one of them but if it isn't then this problem would not be of concern.
@@TheEngineeringHub I thank you for your very long and kind answer! It's true, I was watching a string of your videos and my comments may have lagged. -- It varies in Sweden, of course; a lot of heavy silt/clay soil in some areas (old sea-bed), a lot of moss-covered granite in others. But wood is only 3x more flexible than concrete, eh? (In Sweden, it's usually fir, the older houses have the best quality.) Then with global warning and resultant longer, intense dry periods and sudden rainstorms, we should start getting problems with those small log houses, as well...
The 3x flexibility comment is a bit of a simplification. The Modulus of Elasticity (MoE) alone of concrete is about 30 GPa where wood ranges around 10 GPa (inversely proportional to flexibility). But MoE is not the only factor, the length of a member influences its bending flexibility the most. For example having
- A 10 m steel rod of diam. 3 cm
vs.
- A 10 cm wood rod of diam 3 cm,
The shorter wooden rod would be much stiffer and harder to bend even though wood is a more flexible material. The cross sectional dimensions further influence the flexibility in a non-linear fashion. All together, each structure would be a bit different but in general for members of equal size wood would be more flexible.
@@TheEngineeringHub Now THAT'S interesting. So real log cabins, with wood logs at 2+- meters (said logs resting on, not attached to, each other - except at the ends) would be flexible. I must say I was thinking in comparison to concrete, but then concrete is steel-rod-enforced, of course. THank you for tutoring the uninformed, it's fascinating!
7:25 Case 2 have longest friction surface, that`s why it have the largest safety factor. Longest friction surface provided by geogrids.
Engeniging hub, geo-mechanical tasks are very hard and for my opinion are the most interesting for engeneers. Thank you!
Thanks for the comment Roman!
I wish this was available when I was studying civil engineering!
Very interesting. We have some failing retaining wall around where I live.
I’m considering to do some alterations in my garden which involve shifting a retaining wall back by a meter or so, and to also place it against my single brick layer garage wall, but have no knowledge of what makes a retaining wall to be strong, so this video is a useful starter. I’ll dig out your first video as you suggest, and have a browse around your channel to increase my knowledge of this topic. Thanks for the video!
P.S. I’m not sure if my plan is even a good idea as I don’t want my garage wall to collapse(!), so will also seek professional help if I decide to proceed
Love these videos and the EXCELLENT graphics! I'm a multi-family developer and need to crash course my way to soil, civil and structural engineering...would you please do a video on the most favorable to least favourable soils for low, mid and high rise residential construction??? And another very useful video would be "how to read a geotech report on a development site?!"...I think you would get a MILLION views on that!!! thank you!
For my work I come in contact with soil injection. This is new to me. As I live in The Netherlands, your videos help me to understand about the different soils and how they react. So these videos are very helpful for me.
Thank you an keep up the good work 👍
I've always wondered why there is more geometry involved on the backside of retaining walls, ever since I saw what the flat walls of a canal lock look like on the back side facing the soil. They tend to be stepped so there is more pressure pushing down at the base of the wall. So I have to think there is some sort of shape or set of curves that would almost interlock with the soil it's trying to retain. I'm picturing the back side looking like a 3 dimensional jigsaw puzzle with longer pieces at the bottom. Or a jumble of tetrapod shapes facing the soil like you would with a seawall. All of course would be out of sight in the finished wall.
Man, keep on this subject, got instantly hooked on your chanel
Thank you Jesus, more to come!
Would these principles apply to basements and other "boxed-in" structures as well?
I'm in the midst of building a dug-down greenhouse, about 150cm/5ft deep.It's underground structure consists of a solid concrete footer with reinforced leca brickwork the rest of the way up to ground level.
Could poor insufficient drainage lead to any structural problems down the line? Seeing as the longest side is only 5m/16ft in length, the depth of the footing and the quadratic shape of the structure being stronger than a free standing wall, I never gave much thought to the drainage. I'm now wondering if I may have overlooked it's importance
Great explanation of the performance capabilities (or failures) of different retaining wall designs! Keep it up! (the videos, not just the wall!)
Great video on soil mechanics and retaining walls.
Thanks Sir for this nice presentation. Would love to view more of your contents.
More to come!
Slope Stability!!! That issue makes our mountain side projects freaking twice as expensive sometimes. I need a video to show contractors
Yup it's coming up! But yeah slopes can be a pain (i.e. very expensive to control) if they have poor soils and suffer from instability
i´ll wait for the 2nd part. Great video
Please continue to go into more detail I love the analysis
These videos are great, thank you very much for the content! Part 2 please!
Please make a more detailed video on drainage systems for retaining walls. This information is very helpful in landscape construction projects im taking part in on a generally steep clay/silt rainforest climate area.
I'm working on a problem installation on the coast, where inside of a large rectangular concrete box is spent nuke fuel 53 feet from the edge of a bluff overlooking the bay and directly across from the bar of the bay. The top of the concrete box is 44 feet above sea level and the box is somewhere around 14 feet high, buried up to its lid that projects about a foot above ground.
The soil is nothing more than sand and that sand bank used to extend further out into the bay, 1400 feet more, but has been eroded away at a rate of 30 feet a year until a large amount of large stones, (rip rap or revetment), was placed against the bluff.
My complaint is this, with no pilings under that box or any other form of support, the full weight of the box, somewhere around 600 tons is resting on nothing but sand, and the sand under the box is bearing an immense amount of weight, so what's going to happen when a storm comes into the bay with large waves and starts breaking on the bluff. It'll denude that bluff face in no time leaving exposed sand and once those waves start to hit the bearing sands, they will liquify in a heartbeat, bringing down the soils above them right up to the face of the box which will allow the box to tip over, and if it does that, then we have a nuke disaster on our hands.
I hope I was clear in my explanation, and if I was, does my reasoning make sense?
Most of the small town that I live in is on the Ohio River and is a sand plateau. My property has what was the end of a dragline set up for mining sand. I've lived here for about 25 years. The whole time I've tried to figure out how to solve br bracing for about a 20 degree off vertical thirty-foot drop that is within 10 feet of the neighboring property at the top. So, I'm very interested in your lecture on retaining walls. Thank you very much! This is in a residential neighborhood of mostly single-family homes.
excellent video I enjoyed it certainly hope there is a part two
Part 2 would be great, please! 👍
I'd definitely like to know the current best practices for drainage depending on different soil types
It's been a really helpful piece of information. It's really helped me understand more on the behaviour and failure of retaining walls
How do you find a retaining wall/gravity engineer?
Where do you go and what do you specifically search under?
very good presentation, and the results of the FEM simulations to illustrate the examples were AMAZING! Congratulations!
Thanks, Rodrigo. We appreciate your support 🙏 it means so much to us!
What they said. I need to watch more. Thank you.
Will definitely like a part 2. Thanks for this one.
This was really interesting, but left me wondering how ancient civilizations did retaining walls so well. We have been learning about the Inca and talked about the steps they did around their cities and within them. I know their are so many other civilizations that did steps too. How did they do them so well?
This is outstanding! Something left out, however, is longevity. Let’s say someone correctly crunches the numbers and builds a safe retaining wall, atop of which they construct a gazillion dollar structure that should last a few hundred years. Will the retaining wall last that long without re-shoring?
I would LOVE a video on proper construction of retaining walls and drainage.
what is the software used at 6:40 ?
following
Following
I have a question. I'm adding a low footer bed to a front drive that will only be about 18-24 inches. how high do I need to start worrying about pressure of the soil against the low wall. I'll be using cement breeze blocks and the bottom half of the bed will be type 1 rubble. with standard soil on top. I need it to withstand someone standing on it. I was going to use standard cement to adhere the blocks together and was thinking of putting steel rods into the concrete floor that is the driveway at present. thank you.
Good job guys! Dynamic visualisation helps so much, in contrast with the books where it is static. Thank you
Great Explaination regarding technical issues of retaining wall. One thing I want to add that it would be good if the types of retaining walls against different factors were also breifly explained. Keep it up.
Practical case for any expert viewer here : My 30 year old 4 meter high wall was pushed out some degrees after a rainy year . Now after a very dry year there is a gap of 6 cm visible right on the inside of the wall going pretty deep. Do we leave as is, do we fill up with gravel and improve drainage, do we try and bring the wall back with some anchors or add extra fibercoating to the outside. Any idea is welcome....(no guarantee I understand)
Hi, I have a slope and want to level it up with a retaining wall. Do I have to dig all the lawn on the slope? Or I can simply add back fill on the lawn?
Please dont. The original surface will become a slip plane, always work the soil (cultivate it in some form) before adding backfill.
Thankyou. I discovered your videos today and love them. The use of animations to communicate ideas is incredible. Would have made studying engineering a lot easier in understanding the concepts
Thank you Prando 🙏 comments like this give us all the motivation needed to keep going
Keen to hear more about retaining walls.
Should the same approach be taken for a smaller retaining wall that is about 8 inches in height and 6 inches in width that will run along a black top driveway? Thank You
What safety factor is obtained with interlocking compacted back fill with a reinforcing grid and drainage?
Nice educating course..... but is drainage below the retaining necessary when you can easily design a overhead (on top) drainage system
What about construction principles of “traditional” drystone retaining walls, i.e. base of wall as thick as wall is high, and leaned into the slope 2” for each foot of height?
Can you guys recommend me some practical rules to build a retaining wall in a slope or how to stabilize the slope? The walls could be 5 feet tall.
Great videos for visual understanding
We have a proposed 1.4m concrete wall. Can we add geogrid and does it have to be embedded into the concrete?
Yes post a video for each type of failure with calculations.
just mind blowing! Please keep making videos like these and we'll definitely like part-2 of this video.
I'd like to see a more in-depth presentation of Mohr's Circle. I'd also like to see an example design calculation.
Parker's Reinforced Concrete Design is an excellent guide in this regard.
As mentioned in other comments, expanding on each general example with design and load specifics would be wonderful to some of us.
Thanks for the feedback Sequoyah, this series will continue for sure.
You said any comment?? OK...
Now we have an idea of (some of the) factors involved in building lasting retaining walls, how do we factor in shock loads like cannon fire on how the wall and soil performs? (Fortress walls, typically loose (compressed) fill with solid face). Passing vehicle or train loadings (assuming the retaining wall is for road or rail)? (Yes, I might have a wee bit of interest in historical stuff just because it is cool to know how things work).
I really liked this video and would like to hear more, especially regarding soil movement and foundations in sub-arctic regions. For some reason I love listening to enginerds and sometimes even understand a bit of it.
Thank you for the video. Love the visuals.