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Grady why don't you reach out to Pavement Engineering Incorporated in California. They have PhD's in concrete, I think it would be fun to see you go on a project with them, to help them design a bridge over pass or something. Then to see how they deal with seismic, wind and soil issues. It would be cool to see the people who design these systems. I know one of the founders, Paul, who has now retired. Cheers
@PracticalEngineeringChannel Hi Grady! Loved the episode and reminded me of something I've been wondering about. Would you be open to a topic suggestion? I'm fascinated by marine engineering projects, and love learning how things work. A while back a crane standing on spud barges in Alphen aan den Rijn, fell over while lifting a bridge deck at 52°08'05.4"N 4°39'47.5"E. Here's a clip : ua-cam.com/video/NdUfftG7s0s/v-deo.html What exactly went wrong there, and (assuming lifting a bridge deck while afloat on such a narrow river is even possible) how would you do it differently?
As a retired civil engineer I just love your videos. You have such a gift for explaining technical items in such an understanding way. It’s great for the general public to be able to get a general idea of how engineering affects their daily lives. Keep up the great work!
I've always wondered what kind of headaches it causes watching construction. The tolerances for anchors /supports in precast are exceptionally tight. When we have to install anchors, it's always after the concrete is cured, making it a bit easier, if a bit dustier.
I was about to say the same thing. I know the animations etc must take a huge amount of time to prepare but it really makes it easy to visualise and is so much easier to understand.
I was once involved in the design and construction of a 6.5 meter ku-Band satellite dish. The foundation work for that was more work than assembling the antenna itself. Not only did it have to have a rock solid base plate, it had to be remarkably stiff to resist any deflection under wind loading. Just a milimeter of deflection down on earth means huge differences at the satellite 35,000km away. Furthermore, because we built it in Finland, the foundation had to be designed to work with the local frost line... which was not shallow. It was a heck of a fun project to be a part of.
Gotta love stress/strain interactions! The demonstration of stepping on the different thicknesses of steel, over alternating colors of sand, really brought back some memories. 30 degrees and Pore Fluid Pressure....
In the early 1980's, I worked for a company that built / installed canopies for gas stations. One customer that had a canopy by a different company, called us to come fix his canopy. It was jumping up and down. You could see the canopy pole actually sliding up and down in the concrete. The base plate was buried in the concrete ( about 2 years old ). So, we jack hammered away some of the concrete and fortunately the easy solution. The installers had NOT tightened the nuts on the anchor bolts. So, we tightened them and poured new concrete. So, it had taken that 2 years for the wind forces to grind away enough of the concrete to achieve enough movement to cause alarm.
I regularly design base plates for industrial gearboxes, mainly for use in waste water treatment plants. We mainly use stand off designs for that, though some customers prefer a flange mount. This was a great basic summary and I very much enjoyed the video. Always love your content and the scale demos, keep it up!
@@joecummings1260 Mixers, aerators, and clarifiers. Our drives may be used for thickeners, but our SAP system can be weirdly limited on application specific selections and our sales guys don't always clarify things further to us... which can often be frustrating and cause us designers to go back to sales for more information. Don't know why they never seem to learn from it either. Can't say I've heard of DBS Manufacturing until I just Googled it. I work for SEW Eurodrive.
Honest question? Is there a competency crisis emerging in your field? I'm fascinated about this stuff. Lots of fields we take for granted have a lot of old guys and not enough young guys going into it. Curious if this applies to your field too.
@@cendrizzi thankfully it doesn’t seem so. My department has a really good spread of experience and ages. We have 15 engineers/drafter/technicians and we range from ~60yo to just out of college though the ages are heavy in the 30s. In addition, we rotate 2 co-op engineering students on 6 month internships every year with a program with Clemson University and we’ve hired several of them after the fact. I think our field seems to be pretty stable at the moment.
5:51 Fun fact: the concrete design code's section on anchors (ACI318) was SO bad and hard to use, that "Appendix D" became an in-profession meme, where you can compare any calc to Appendix D as a quick gauge of how annoying it would be ("I can do that, but it will be an _Appendix D_ level design"), so much so that when they reworked the code, it was moved from Appendix D all the way into Chapter 17, to help lose that colloquial baggage.
@@standout8616 Isn't it funny how that happens? In reality, you've probably seen/heard the word hundreds of times, but now that you KNOW the word, your brain actually _recognizes_ it. Tho, I swear, this happens to me all the time too... Brains are weird, or maybe coincidences are weird. Probably both.
Hey! I actually have a real-life use case that goes with one of our videos. I designed and helped build an astronomical observatory. Two concrete piers are located inside a small building with a roll-off roof. Telescopes and their mounts big enough for this project are heavy beasts, and getting them connected, level, and at least somewhat isolated from the concrete piers -- for both vibration separation and moisture coming up from the soil underneath -- led me to use L-shaped stainless steel threaded rod, with thick stainless steel plates and leveling nuts. I didn't have engineering software or the knowledge needed to accurately size the materials needed, so I did what I often do when making something structural: obvious overkill. The scopes are so strongly supported and separated from the concrete piers that you can whack on the piers with a large hammer and not see any movement at the eyepiece of the scope, even at high magnification. (Yeah, I wanted to test this, so I did, just once!)
Ha, I was going to mention this looks like the pier plate of a observatory mounted telescope. :) I'd love to see a Practical Engineering on big observatories.
I had heard on some of the telescopes, the bases are floated on pools of mercury. The mercury provides little friction to turning and it doesn't transmit external ground vibrations well which if you have very sensitive equipment and are taking photographs of objects far off, any little movement can mess them up.
As an amateur astronomer without a permanent observatory for my telescopes (although I know people who have them), I appreciate what you did. I am also a civil engineer who occasionally designs foundations, anchors, and base plates for small signs and light poles. For my last project of this kind (modest-sized light poles at a park, about a year ago), I used the Simpson Strong-Tie Anchor Designer software, which is free. However, if you don't have an engineering background, I suggest getting an engineer to do the calculations, especially if the calculations must be submitted to an agency for permitting. L-shaped anchor rods are fine for modest loads, but if you get into a situation where anchor loads are high, I suggest hex head and heavy hex head anchor rods.
As a corrosion engineer, I (almost) missed the ( most important, of course ;) )failure mode of corrosion of the rebars or bolts until I heard a mention at 9:09. Thank you, Grady.
Anchor bolts are a pain to get right even after the design is set. I was the production manager for piers and light pole bases at a precast concrete plant for years, and the thing that demanded all of my focus was the anchor bolts going into them; what's the size, the spacing, how far up do they project, etc. All that information was needed before I could schedule something for production and it's astounding how often contractors placing an order just couldn't give me that info when asked. All the fretting over the bolts was to avoid getting the call that the 20 foundations we built and delivered wouldn't fit the baseplates on site.
Wouldn't it be your job to tell them what is needed for YOUR precast products? I am not getting why a light post wouldn't have the baseplate screws already calculated for. How much do base plates cost compared to say a 1 inch to 1-1/2 for example? I am just wondering why any of them would even bother for minimum specs. I feel like over engineering it is not an issue. Here everyone gets a 2 inch thick baseplates, and anchors as thick as my wa
@@JetSkiSuper7 Sometimes I'd get a template, sometimes I didn't. I've been given the wrong template before as well. One time I even got a template that was printed at the incorrect scale and so the bolt spacing ended up being too close together. When the information was liable to change hands several times before it got to me, I just had to be diligent in making sure everything was correct.
@@JetSkiSuper7 We are a sign contractor that has always built (and wants to build) our own anchor bolt forms. Increasingly, the industry is moving to other contractors on site digging the footing, building the cage, pouring the concrete, and placing the bolts... The track record "screwing up" is much closer to 100% than impossible. Bolts on the wrong centers, bolts are as plumb as crooked teeth, not enough thread above grade for the leveling bolt + plate + clamp bolt. The list goes on.
An alternative to base plates for smaller sign poles and lighting poles are prefabricated foundations with a hole you insert the pole into then use wedges and a cover plate to stabilize it. They're really popular in municipalities here in Sweden as their lifetime often supercedes the poles themselves, lasting 30-60 years. Lookup cetong and meag.
Some contractors screwed this up in New Zealand earlier this year. They were cleaning the base plates of a transmission line and unscrewed 3 of the nuts, leading to the tower falling over and the whole northern region of the north island losing power for a bit
@@davidwilliams9302 Likely cleaning off rust, and instead of doing one at a time, which would mean essentially taking 4 days to do it, assuming they were removing one nut set at a time, spraying with high pressure water to remove rust, then applying a protective first coat, then running the nuts back down and then a second top coating. Instead they undid 2, got half way, then went to undo the third leg, and found out that because of cable sway, and likely the cable direction changing, that the third one meant the side tension from the direction change pulled the entire tower over, as the last one was on the inside edge and thus still under compression, while the other 3 were under tension.
I must say this channel has genuinely shifted the way I view our roads, plumbing, and electrical services. The true level these systems must operate at is insane
"The true level these systems must operate at is insane" - This is especially true when you realize that many (if not most) of these systems are forced to operate for decades longer than originally designed due to the owners' refusal to update/replace them.
@nomore6167 oh absolutely. And especially when you take into account that there are a lot of mistakes being made everyday on these systems, yet they continue to serve and achieve their goals. Human engineering is amazing
As a structural engineer who mostly watched your videos for the geotechnical side of things, it's rather pleasing you take on a different approach. I appreciate in your way of presenting the general ideas of construction engineering through exaggerated home brewed experiments. I feel like younger generations of structural engineers forget that half of our job (considering our insurance and the liability side of things) is to understand which details require attention and which don't About another 25 percent is through understanding and judging a contractor's capability to carry through with the design. What i love about my job as a sturctural engineer is how it often comes down to seeing things deform in your 3D mental space and never forgetting Hooke. I'd appreciate immensely if you would kept the "practical engineering" side of things and showed structural engineering with heavy foam blocks (simple bending and shear) or spagheti (instability). Regardless always a pleasure your videos are always a pleasure! Cheers
Hooke's Law, man. I've seen that many engineers, even at my own company, that just don't get it. They think you can put a simple 8x8 DFL wood sleeper across some steel joists and get RIGID load distribution. Hardly. All the load will go on that first joint and the wood will just defect, barely loading up the other joists. We had an as-built condition that wasn't quit working, so the contractor came back to us, and that engineer had left, so it was up to me to verify the design. As it was already fabricated etc, we really wanted these to work, so I actually did the deflection calcs for the wood and the steel, with different loads going into each thing, and found it wasn't even remotely close to working. Then we had to redesign everything all because our previous engineer forgot about deformation compatibility.
Up her in Quebec, most new light poles are now design with standoff base plates to prevent corrosion of the interior surface of the pole. De-icing salts combined with high humidity inside the poles are just chewing up pole otherwise. Including aluminum poles.
@@peterfitzpatrick7032 Normally with aluminium poles the bolts are 316l stainless steel, which suffers less from corrosion with aluminium, especially if you use a anti corrosion inhibitor liberally during installation. by me there are aluminium gantry units that have been up for close to 40 year exposed to salt spray, and aside from being cut down for scrap metal, they are surviving well.
0:59 I am strangely excited about this. After years of watching you and others about infrastructure, it's great seeing an episode on the one singular entity that literally ties everything together in the modern world.
Not quite everything, but quite a lot, especially in the commercial space (where steel construction is common). You'll often find the same anchors in residential construction, just anchoring a sill plate to the stem wall. Or in concrete construction, you just extend the rebar up from the foundation to tie into all the column or wall reinforcement. Any time you do have some large steel member, tho, either a beam or a column, you can expect to find a steel base plate going into concrete.
Good job covering anchors and baseplates. Worth mentioning is also when you have stand off baseplates and shear forces you introduce a moment force in the anchor, and they have almost zero capacity for that. It's a headache to design without grouting - you end up with anchor dimensions that look way too big compared to the plate/construction element.
The TIA (Telecommunication Industry Association) structural code, which covers the huge poles that go up like 150-ft and support massive arrays of antennas (and also for guyed towers up to THOUSANDS of feet tall), expressly FORBIDS the use of grout as a compression element, for all the reasons stated in this video. You do end up putting a LOT of bolts that are large diameter. For example, a 40-in diameter pole might have (30) 1.5-in anchors, or even 2-in diameter anchors if the pole is really tall or has high wind loads -- that's a bolt spacing of only a couple diameters on center.
Ooh, this one brings back an unpleasant memory. Many years ago, in college, I worked on an industrial construction site one summer. One of the assignments I drew was to use a pneumatic tool to scarify the top surfaces of the concrete footings for the process building, so the grout under the vertical columns would adhere better. To keep the dust down, the tool had a water sprayer built into it. I inevitably ended up covered in mud made from pulverized concrete, and within a few hours the lime in the concrete dust disintegrated my shirt and, uh... let's say certain sensitive patches of skin underneath it. Naturally, my foreman found a way _not_ to report the profuse bleeding as a work-related injury...
Throughout my career as an electrician I have installed thousands of pieces that required anchor plates. From light poles to motors and motor control centers to substation systems and fences. Very good video!
heh I started going for ceramic materials sci, 3rd year no so good, ended up mechanical testing hvac materials 25 years later. Should have started in mech eng school.
Thank you Grady. I work in fabrication of DOT signage structures. I have been waiting for this very video ever since I found your channel so many years ago. Excellent job and keep up the good work.
@@cruisinguy6024 lol. No I don't deal with the signs themselves just the support structures. Over my 18 years I've built structures for most of the eastern US.
When I had my RV and mobile home repair business, I got a lot of calls to relevel mobile homes. The problem usually was that the concrete blocks used as piers sunk into the ground from the weight of the mobile home. My solution was to install a level 2' x2' 3/4" pressure treated piece of plywood under each pier and reset the concrete blocks the proper way and doubling them as a pier. The plywood spread out the load and would only sink 1/4"-1/2" rather than half the width of a concrete block.
I’m from Brazil and I’m a engineer student. Just amazing that right now I am studying steel structures and projecting a base and you make this video in a good time
Also remember that additional plates can be embedded in the concrete as part of the anchor bolt structure. Those can help distribute both compression and tension forces into the concrete footing.
I've never seen this in the sign biz. That sounds like a headache to ensure that concrete completely flowed above and below the captive plate with no voids. Vibrating will help yet 'faith' sees involved. Obviously you know what you're talking about. Just strikes me as odd. What are the applications?
@@davidwilliams9302 you design the reinforcing such that it is a welded cage, and the mounting bolts are a part of this, with welded on L plates that act to spread the load to the reinforcing, and thus allow it to support the load. By me that was done for light poles with caternary cables, which are repurposed century and a half light poles, that originally held tram wiring. he old poles went down to buried concrete blocks that were cast around them 150 odd years ago, when they were removing them they dug down to this layer, and were using cutting torches. I did suggest to the contractor he really needed to go hire a large air compressor, a generator, and a plasma cutter, as that would have made the cutting a 1 minute process per pole, after digging down the meter to get to the base. acetylene torch was taking him around an hour per pole, they are that thick. When they came back they had a standard 8 bolt pattern flange welded on to the base, and had, because of the length, been powder coated, as there is no galvanising bath by me that can handle a 12m long pole, it is 10m long. But the new bases are a 6 cubic meter of concrete, with a rebar cage in them that incorporates the stud base and a secondary alignment ring that was used to bench the concrete fill to. Each base took a full load of concrete to pour to that level, and the base is buried 15cm under the ground level, with another 5cm of pavement tar on top.
If you mean the template plate that's only 1/8" or 1/4" thick, that has little structural benefit. However, we also often have 1/2" or 3/4" plates at the ends of anchors (headed anchors), which we d4esign for bending forces and do improve the tension capacities.
As a life-long rollercoaster enthusiast, this video answered a lot of questions I´ve had for a long time! Rollercoaster track pieces are often designed with sub-milimeter precision, so I always wondered how they manage to bolt everything together on site with foundations that are not made with that same amount of accuracy.
Consider that much work is farmed out to "lowest-bidder" contractors, and the world becomes a scary place to feel completely at ease ascending a skyscraper or riding a roller coaster. The 1,800+ foot tall CN Tower in Toronto, Canada has an indicator at the top observation level that shows in real time how much the tower is blowing "off-plumb". In Sept. this year we visited the leaning tower of Pisa, Tuscany and was surprised to learn that some time ago, engineers counter-balanced one side with 200 tons of lead to prevent further tilting.
Having worked in some industrial facilities, another place we use a lot of grout is machinery foundations. The machinery often has to be aligned carefully to connect/ interact with other machines, so leveling nuts on support studs are used. Then grout underneath to support the weight and vibration better.
Great video. I've worked as a steel detailer for many years and have had to model hundreds of different base plates, but as a detailer you usually don't get the full picture of why a design is the way it is, you mainly follow instructions from an engineer. You learn snippets throughout the years, but this video really presents a complete picture in a way I had loved to have had back when i started my career.
Hi licensed structural engineer here. At 5:03 you showed J bolts/hooked anchor rods. Please know that these have not been used in years and per AISC, hooked anchor rods are not permitted for tension applications. J bolts fail before their full load, due to the hook straightening and also due to a void occurring above the hook from wet setting. A hex headed anchor rod is far superior for cast in place applications Edit: reading is fundamental. The phrases “have not been used in years” and “we as an industry are trying to move away from them” imply the exact same thing. J bolts are still manufactured and sold and even specced in some cases but that doesn’t justify their use in most applications, especially low/mid/high rises and high wind/seismic applications. There are many types of anchors out there that are far superior in concrete and steel failure modes. Hope this helps
Is this true even for residential applications? I believe I have seen them in use very recently in that setting. They are certainly still sold. Grady's topics aren't limited to any particular genre of construction, are they?
@@tridium-go6hw It's probably permitted in residential applications. Lots of uses for residential, mail boxes, deck posts, fence posts, all sorts of low-load type applications. Probably not for anything structural tho unless it's a very small load.
I don't know if it's permitted, but a whole lot of residential bottom plates are still being attached to slabs with embedded j-bolts in the Atlanta area.
We thought these were discontinued as well. But recently had a structural drawing that called for j-bolts to be embedded in the concrete to anchor down industrial pumps. They can be readily found at home Depot.
As concrete carpenter in my twenties I’ve set thousands of bolt settings for structural steel. Getting them correct was one of the more difficult aspects of my job. I had the best luck just having the surveyor double check everything before and after pouring with the total station. This gave me the best overall results, and we’d still be off a half inch here or there.
I am an amateur radio operator. I have six outdoor antennas. They are all either vertical or wire. Some of my friends have the big yagi antenna on top of a tower. My friends with the huge yagis have to take into account for a wind load with the guy wires, foundations and anchor points. Me? My setup honestly doesn't have any wind load, even though I live in Reno, Nevada, which often sees winds coming down the Sierra Nevada mountains at over 50 mph. My favorite antenna is an end fed half wave that is tuned to 40 meters (it honestly works great from 40-10 meters). It is setup as an inverted V. It has survived all kinds of storms. What it didn't survive was when a landscaper dropped a tree on it. But I fixed it with a little solder and some heat shrink.
Over the years I have done allot of light poles and signs. Since the concrete is NEVER level I always use bottom nuts and washers to fix this. I also extend the PVC pipe up to above the wire window so I can grout the base after. I install a dam around the base and strap an air powered vibrator to the pole. I mither grout very thick, relatively so, and let the vibrators distribute the grout. For bigger poles I use a concrete vibrator strapped to the pole which seems to work really well and provide a void free fill. I then use an oscillating saw to cut back the conduits so I can play electrician. Doing these right are time consuming and somewhat expensive. But spelling out the process in great detail has resulted in my bids, though a bit more expensive up front, being accepted over other contractor's. Further, I up size hardware and tie or weld it to the rebar in the base to assure long term durability and excessive strength. Bases are thee most important part of any structure because there is really no practical way to fix sub standard implementations without resorting to heroic and expensive measures. I am just a dumb electrician but I put in a boat load of thought and effort to assure that my outdoor work is safe and out lives me.
I'm a structural engineer from Belgium and I'd just like to say, I really appreciate the videos on this channel. They're at the same time really approachable for people who don't know anything about the subject, while still giving interesting insights for someone with my level of education. Keep up the good work, videos like this really make my day
I worked at a plant that recycled lead acid batteries so the place was always being rebuilt especially when loaders or forklift hits columns. When we would replace or repair these things the plate would be bolted down with 3/4 inch stainless wedge anchors then lift the roof 1/2 inch or so slip in new column and weld the two Parts together. This worked very well as long as there's not more than 2 levels
As a foundation worker turned engineer, I wish this stuff existed 20 years ago. Thank you for helping explain both of my careers with a one-stop UA-cam adventure.
You timed this one perfectly Grady! I'm designing baseplates at the moment for an experiment at my work! It's for a rain simulator boom arm, that's going to be suspended from trucks running along a pair of goal posts with rails mounted on the top, allowing it to be repositioned for different experiments and to allow access for maintenance of the spray nozzles. It'll end up looking a little like a gantry crane you might find at a dockyard. The experiment itself is an indoor compound slope setup for testing different sustainable green drainage systems. I'm a lab technician in a built environment school at a university in Scotland, but my background in physics and hydraulics, so I'm a little out of my depth for some of these calculations. Learning a lot as I go. Don't worry though! I'm running everything past a proper civil engineer as well! Not ordering or cutting any metal until I can show my work to the class! 😅 Total suspended load will only be in the order of couple of hundred kilos. Still scary if it goes wrong mind!
Being in the industrial concrete and communication tower construction business I really appreciated this video. Using stronger concrete and anchor bolts and doing away with grout was a great move in the industries.
I just made a whole post discussing this. In the more recent TIA codes they expressly forbid grout as a compression element. But I've had to justify existing monopoles or guyed towers assuming the grout was working in compression (it was a valid design then, but not now). I did have photos to see the grout looked fine, but yeah, this definitely impacts the anchor design, making the anchors work at about 350% demand (mostly due to bending) when you suddenly are just supposed to ignore the grout lol.
Same thing in the utility and power industry for substation construction. Non-grouted BPs are so much better. I've seen SO many structures that have rotting base connections because the moisture and water over the years has been trapped inside of the shaft with no escape because of the grout pad.
@@DirtyD07wait, grout like bathroom grout? That stuff barely holds up in domestic settings, they were using it to hold up poles? Edit: the video reached that part. Huh.
I'm retired now, but worked most of my career in engineering at refineries and petrochemical plants. Base plates for motors, gearboxes, compressors and pumps used epoxy grouts. Very robust, waterproof, void free, etc. Used on anything from 1hp injection pumps to 12,000hp compressors.
Back in the mid 80’s I invented the Immured Foundation to attach electrical transmission poles to drilled pier foundations and eliminate the baseplate and anchor bolts. The pier reinforcing steel was left extending above the pier and the concrete set. The pole was set over the extended reinforcing steel and concrete placed inside the pole over the top of the rebar. The length was the greater of 1.5 times the pole diameter or the development length. 10 to 15’ was common for these poles. The problem with anchor bolts has been around for a long time and I have seen a lot of mistakes made and fixed a lot of them. Most are self inflected by the original design engineer. The Immured Foundation was invented to eliminated the anchor bolts for large steel poles. If you Google “Immured Foundation patent” you will find the details. It does take special software to design.
That seems to just be an embedded pole. Dig hole, plop in the base pole and a rebar cage, fill to grade, add new pole section, add more concrete. The images didn't help me at all, unfortunately, but it sounded like you're just constructing a grouted pole. I'm sure I'm missing something.
@@kindlin Direct embedment works for the steel LD poles. You do have groundline and inside corrosion issues making it unreliable for major poles and they lacked the strength for angles and dead-ends. You also need a larger diameter and burry a lot of steel. LD poles are a replacement for wood poles. The Immured Foundation was invented for an odd reason and proved to have other advantages. It does not make sense for every application. The Immured Foundation was invented to reduce the drilled pier diameter. A new group of poles was developed that required an auger lager than 10’. The 10’ was the limit of the company’s equipment and to go lager ment a new larger crane drill rig and augers or contracting the project out. The crews also hated dealing with 42-2.25”x13’ anchor bolts. When an anchor bolt was bad, it ment the bolt was cut off and the pole capacity derated. Prior, we had tried just embedding the bottom section partially in the pier. This installation went poorly. The pole was embedded partially in the pier. This ment the pole had water drainage issues and subject to filling with water. Also it had a larger diameter than the Immured Foundation. The pole base had to be supported by a crane overnight for the concrete to set. This arrangement way bad because it was subject to weather and breakdowns and security and safety issues. Additionally, the crane was not working on drilling holes. This would mean a second crane just to hold the bottom section. The Immured Foundation solved all these issues plus eliminated the pesky anchor bolt issues. The pole manufactures were kept in the dark on the first project about how they were being installed. Once they found out they loved it because they got rid of the anchor bolts and baseplate problems. The only way to tell the difference between a direct embedded pole and an Immured Foundation by looking is the Immured Foundation has drain holes about 10’ above ground.
@@TexasEngineer All of that makes sense, thank you. But I'm not much closer to understanding the difference between an Immured Foundation and a standard embedded pole. Is it that you extend the concrete up past grade to alleviate drainage issues? It's not too uncommon to fully grout steel tube columns/poles for structural purposes, which sounds kinda like the bottom 10-ft above grade, but it sounds like this was done for maintenance and construability reasons.
Another example where you can see development over time of baseplates is railway electrification, at least in my area. The older type was coated steel or reinforced concrete poles, sunk into a hole in the concrete bases, which were then backfilled with more concrete and covered in tar to keep out the moisture. The newer types use galvanised steel poles bolted onto standoff foundations. I took a train regularly where this was visible quite clearly when a branch line, which was electrified recently, merged with a mainline, which had been electrified for decades. The old mainline supports used the type sunk into concrete, while the new branch line supports were bolted onto standoffs. They recently relaid some track on that site, straightening some points and requiring the power infra to be replaced, so now the difference has disappeared, but there are probably still places elsewhere where the difference is visible if you know what to look for.
As a structural steel fabricator and welding inspector, I work with all types of baseplates everyday. I have seen some pretty interesting designs over the years from you engineers 😂
As an iron worker. My job is to install those columns. I often need to torch cut, re-weld, or make adjustments to base plates and columns. This was a neat video
There's some serious engineering behind base plates like this, especially for wind turbines. One of the case studies we went over in college was wind turbine foundation bolts. In this case they were installed with leveling nuts so instead of behaving like a typical bolted joint which experiences effectively zero fatigue unless the clamp force is exceeded, the bolts were experiencing fully reversing compressive and tensile loads. Thankfully I believe it was caught in inspection (they retention/torque turbines as part of annual maintenance).
The elephant in the room!!!!! Unfortunately, while stand off base plates are very convenient for aligning, they do contain a fatal life limiting flaw as @JamesSeedorf has very correctly identified. The flaw is not considered by design standards or by designers. i.e. The thread below the levelling nut. Stand off base plates are the only common situation when cyclic reversing loads are applied to un-preloaded threads. Even ignoring bending, the stress range in the un-preloaded threaded section of holding down bolt is a small fraction of the endurance limit of the bolt material. (The zero bending is a myth because concrete is not a theoretical anchor). You don't believe me? I would challenge you a) To calculate the load carried by each bolt. esp. in a 10 bolt base plate. You cannot. The individual bolt load could be anything, some bolts could even be under net tension due to dead weight only! Why ? The load is dependent on the installer. b) To calculate the fatigue life of base plate assuming that the bolts are carrying a theoretically equal load distribution. This design has been subject to many research papers. For some reason, the stand off base plate design is still permitted. Particularly, for high mast light poles in windy areas. If you do not want to do the fatigue calculation, think of this example. Would you drive a car if its wheels had been "widened" (tracking increased) by adding nuts on the inside of the hub to longer studs? In effect, turning the stand off based plates by 90 deg and then applying reversing loads.
I’ve done a lot of steel columns w/base plates, leveling nuts and non-shrink grout. Once I noticed my grouting crew mixing the grout much more soupy than I preferred to see and definitely with more water than was spec’d on the mixing directions was being used. It was almost the consistency of crème of tomato soup. To give myself some assurance that things were ok, I had them mix a batch for some test cylinders with the grout, at the same consistency. When we broke them at 28 days, they had indeed lost some of the prescribed strength. Instead of breaking at 8K-9K psi, like the product spec, we were getting around 7500 psi. I felt good about these results because the steel columns were sitting on foundation pads of 4K psi. I like the idea of getting full bearing coverage of the base plate w/the soupy mix as opposed to using the dry packing method where you can never be sure that you’re really getting full coverage and told the guys to carry on with the wet mix.
Ditto! When I first started playing, I listened to a lot of songs with the bass track removed which really impressed how integral bass was to the foundation and feel of a song - without it, everything feels flat. Bonus relevant joke: How can you use a bassist tell if a baseplate is level? Have us stand on it and see if the drool comes out of *both* sides of our mouths!
Crazy this vid came across my feed. I have wondered about this exact topic for a couple of years now. Never looked into it, but just an idle wonder. Specifically the gap between the base plate and the concrete for large signs and light posts. Hearing your explanation makes perfect sense that it is simply a matter of efficiency, once a thicker baseplate and heftier anchor bolts are specified. I suspected it had to do with movement allowance at the base and cracking concrete, etc., and I suppose if that’s all it was it would be better to use a hard rubber gasket of some sort between the plate and the concrete. Anyway, thanks for taking the time to explain this to us non-engineers!
I work in drafting design for gates and fences. I design around baseplates all the time. we mainly use standoff for adjustability. I never payed any mind to baseplates before I got this job. thanks for this video! super interesting to think about even more than I already do.
I watch a lot of your videos and try to like as many as I can remember to. But your mentioning of different abstract units like "kilogradies" reminded me why I love your videos.
I'm in structural test for large aerospace structures. When we attach a steel base structure to a concrete "floor" of our test stand we level the base about 1" above the concrete and use a 2-part epoxy grout to fill the space between. High-strength steel studs that were previously threaded into permanent anchors in the floor are then used to pull the base hard against the epoxy grout after it has cured.
hopefully the part of those steel studs that are in the grout are sleeved so they pull the plate to the floor, and let the grout section stretch to provide the load. There have been one or two instances of post stressed members not being free to move, which has resulted in the actual substrate failing near the ends, because the tensile members were too firmly bonded to them while the middle was under no tension.
@SeanBZA yes we use foam donuts around the studs (they seal against the bottom of the steel and the concrete) to prevent the grout from getting the stud threads
In NZ, work has been done to make roadside signs friable/frangible. These are designed to collapse into harmless pieces on impact. These can often be simply reassembled. With traffic, this fail safe mode can be directional, check out ILS antenna at airports.
The original machine had a base plate of pre-famulated amulite surmounted by a malleable logarithmic casing in such a way that the two spurving bearings were in a direct line with the panametric fan.
Spread the load. This is also important for freight, especially aircraft, as the limiting factor is often the cargo floor and you spread the load with either a pallet or shoring, often just wood planks that allow you to load objects with very small contact points on an aircraft cargo floor that is remarkably thin, and thus light.
Yes, I was tasked to do a pre major overhaul weighing of a helicopter, and this was 45kg over the last recorded weight, simply due to the floor of the helicopter being now almost entirely constructed of Araldite epoxy. the issue was that using it as a gunship, with a 20mm or 16mm cannon in the side, essentially used to tear all the mounts, both for the cannon, and the pilots, out of the honeycomb floor. So they would simply place an aluminium plate under, temporary bolted to the "good" floor, then pour in epoxy (5l cans, none of this little tube stuff) and have the mounts held in position till it cured 24 hours later. Remove bolts and fill the holes with 5 minute epoxy. Then spray with black enamel, sprinkle a heavy coat of dry sand on top, and leave for 15 minutes, then brush off excess sand, and paint again with the black enamel. Might last 2 missions, or 500 rounds, before it ripped out again. basically the entire floor was a solid epoxy block, with lots of plates under it to act where the patches were. Entire floor was replaced with new honeycomb material.
Shoring and leveling of loads is also key with containerized freight. Not only for the aircraft load but in general handling of the container. Too much weight in one spot and the container is far harder to handle and push around, wanting to pivot at the heavy load point.
I was part of the team that assembled the concrete-imbedded bolts for a roller coaster at a major theme park, and part of the design actually included an integrated "top" to form the concrete where the base of the columns would eventually sit. Quite a fun project, actually.
This explains so much of the structural instability issues I ran into with my early work with Linoln Log towers. Knowing this could have saved the lives of literally tens of plastic army men. Rest in piece, flamethrower guy (and the poor grunts standing next to him).
For 33 years I've always been interested in them and always found myself wondering how these worked. I really appreciate you making this really specific content :)
Baseplate detailing is a great start to drafting. Repetition is key to getting the hole dimensions and sizes, thickness of plate and any other engineer specific requirements just perfect. Good luck! (Senior design draftsman 25+ years)
Love this! We always manufacture our posts intentionally 25mm too short and supply "packers" to make up the length, the packers are 100mm square and you can plumb the columns around them with the nuts on the anchor rods (obviously only after the chemical fixing has cured). This also helps to keep the anchors in tension so the main loading through the post bears nicely on the "5 star - non compressible grout" between the baseplate and the footing.
I’ve noticed them my entire life but never really paid attention to them. Thanks for explaining the engineering behind them Grady 🤜🏻 you’re one of a handful of UA-camrs that I watch their videos as soon as they come out
Yup looks like a typical day in Vancouver! I believe we’re looking up the hill on Burrard near the station, my morning commute to my first job as an engineer 😅
I'm so glad I found your channel, your explain the dynamics of engineering in an incredible way for someone like myself with no engineering background, but love doing DIY - Thanks!
5:30 When putting the anchors in the wet cement a cage of rebar around the anchors can prevent any problems with cracking. And it is relatively simple to bolt them to a stabilizer attached to the form so they stay in the correct place.
Yes, adding rebar all around anchors helps a lot, it basically precludes all the failures except steel yielding and bond shearing, but I mostly work in existing construction, where we are post-installing anchors with no control over the existing rebar, and can, at most, say that there is a side bar to prevent concrete breakout.
Thoroughly appreciate your content. I work construction. This week I was building concrete bleachers for a baseball field. I can follow instructions, but the practical physics are nice to understand.
I built a 75 foot long tilt over radio tower for my antenna's. I am no engineer, so I over built it. 3 yards of concrete, over 300 feet of rebar in the base, 12 -5/8 anchor bolts cast in place, and all leveled with nuts. I have 1000 pounds of steel in the self made hinge base and truss system to lower the tower. It didn't break, at least not yet.
I'm laughing because obviously a straight antenna doesn't have the wind load or leverage of a big square sign, but "3 yards of concrete" and "75 feet tall" in the same sentence is giving me the sweats!
I wonder if I saw you post this same thing years ago. I don't remember which video or channel, but I recall a very similar comment. With a guyed tower, the base foundation just needs to be wider to support the extra down-force froim the guy wires, it shouldn't need much in the way of depth or anything like that. I would expect probably a 6'x6' by 2' deep foundation for a 75-tall guyed tower, just bearing below the frost depth basically. Now, the guy anchors on the other hands, those are the really hard things to design. You often need massive concrete deep underground to give you enough weight to resist huge loads from, like, 1000+ ft tall towers.
@@kindlin Our frost goes down 4 feet. The cement is a touch over 3 feet wide, 5 feet long, and 5 feet deep. Its so big because it supports the tower as its lowered. The lowering truss is 20 feet high where the winch pulls from so the torque load is high. My guy's have 300 pounds each of pre load.
@@1958johndeere620 Oh, ok. I'm not familiar with collapsible towers, there must be another tower somewhere that lifts up a guy wire or something to pull the tower up? Or is there a giant motor to torque the tower up, just from the foundation? And out of curiosity, what size guys do you have on that? 3/16? 1/4? At 3/16, the 300# would be just about standard spec (10% BS).
It's a gift to feel more informed after a video on YT! Thank you Grady. (Hope your family has a wonderful holiday season filled with joy and connection--and starved of overly crass commercialism.)
I normally build a ground cage that is set into the concrete with the threaded studs pre positioned. The base plate and post is floated on nuts underneath like examples shown in the video. I prefer this as the structures level can be easily adjusted.
If / when you’re up for it, would love to see more videos on disasters and preparedness (especially regarding the grid) - maybe home generators? No worries if that’s not the direction you want to take your channel. Thanks for the consideration.
Thank you Grady for consistent quality content! I built my garden observatory (a garden house with a roof that can be completely rolled off) on multiple H-anchors set in point foundations of steel and concrete. My goal was to get the wooden pillars away from the moisture of the dirt underneath. That seems to work great so far, but I never found reliable data on how much weight in compression forces I can actually safely put on these anchors.
Thanks great info! Will be putting up car port with some sort of base plate arrangement. On a previous project helped design a moment frame to resist racking. Base plate with L bolts and grout was initially spec'ed, but to save steps/time/cost and increase pullout strength, changed design to sink base plate into the concrete while still using L bolts. With one concrete pour, a portion of column, base plate with L bolts attached were all buried/surrounded in concrete. The column was suspended from other existing structure elements during pour and while concrete was setting. Unique problem with unique simplified solution!
When I was in college, there were many octagonal type poles on the way for overhead higj tension power lines. I always remained confused why the poles are 2 to 3 in higher than the concrete foundation below. Ultimately I started my bachelors in Civil Engineering to find this specific answer, and in my third year during the first lecture of steel structures I finally asked tjis question from my steel structures teacher and got the answer. After that, base plate and anchor bolt design became my favourite.
Working in heavy civil construction for almost a decade, a really large number of light poles along the highway are actually designed and installed with “transformer” bases that are made from a softer aluminum that will tear and break away in the event of a collision. Also, the bolt “holes” are actually slots that are open ended to assist in the break away function. Lastly, due to the overall height of most of them, even if they are hit they usually don’t land on the vehicle that hit them. That vehicle passes more or less safely under the pole and stops outside of the fall zone, kind of like kicking out the bottom of a baseball bat balancing on one end.
Having been the guy who, A) set anchor bolts in wet concrete, B) rough designed pre-engineered steel buildings for quotes, and included building forces to contractors so they could also quote the necessary concrete anchors in their bids, and C) having been an assistant foreman, meaning *I* was the guy who had to *FIX* anchor bolts set in the wrong place, and also had to grout under base plates...I'm invested in this video, even though I'm now retired 😂
Good presentation, as usual. You do a good job of presenting a substantive summary while making obvious the true complexity of the subject at hand. I lost track of the number of times I was told to "just design the base plate", without being given a spec for the loadings, the base materials and the conditions of use.
I have ***always*** wondered about the stand-off base-plates I see on the side of the highway. "No way is that more secure than just bolting it to the ground..." I would always think to myself as a kid. You can only imagine how excited I was to see this video in my feed! 😄
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I linke the safetyshoes you use in this video
Grady why don't you reach out to Pavement Engineering Incorporated in California. They have PhD's in concrete, I think it would be fun to see you go on a project with them, to help them design a bridge over pass or something. Then to see how they deal with seismic, wind and soil issues. It would be cool to see the people who design these systems. I know one of the founders, Paul, who has now retired. Cheers
@PracticalEngineeringChannel Hi Grady! Loved the episode and reminded me of something I've been wondering about. Would you be open to a topic suggestion?
I'm fascinated by marine engineering projects, and love learning how things work. A while back a crane standing on spud barges in Alphen aan den Rijn, fell over while lifting a bridge deck at 52°08'05.4"N 4°39'47.5"E. Here's a clip : ua-cam.com/video/NdUfftG7s0s/v-deo.html What exactly went wrong there, and (assuming lifting a bridge deck while afloat on such a narrow river is even possible) how would you do it differently?
It's a free country use what ever units you want :)
I'd like you to focus on my structural member
Can you stand on the pressure sensor and calibrate your weight to equal 1 unit? Call the units "Gradys"
Calibrate it to 1 billionth so it can be a GIGA GRADY. Capitalization required.
What do you think about "Degreedys"? ... "Degradys"?
not sure the sensor is sensitive enough, a human might be smaller than the margin of error, these are fairly large forces involved
@nickl7488 I hope it is! A lever can multiply the force precisely if needed.
Nah, calibrate to 9000. The only thing that matters is whether whatever you measure is over or under.
As a retired civil engineer I just love your videos. You have such a gift for explaining technical items in such an understanding way. It’s great for the general public to be able to get a general idea of how engineering affects their daily lives. Keep up the great work!
Yes he has that gift ❤❤
One of the things I love about your channel are all the demos, graphics, and animations. They really help make your points clear. Well done, sir!
I've always wondered what kind of headaches it causes watching construction. The tolerances for anchors /supports in precast are exceptionally tight.
When we have to install anchors, it's always after the concrete is cured, making it a bit easier, if a bit dustier.
there's also the jokes. 5:18
me too, even profeshional tv documentries don't do this
Soo true
I was about to say the same thing. I know the animations etc must take a huge amount of time to prepare but it really makes it easy to visualise and is so much easier to understand.
I was once involved in the design and construction of a 6.5 meter ku-Band satellite dish. The foundation work for that was more work than assembling the antenna itself. Not only did it have to have a rock solid base plate, it had to be remarkably stiff to resist any deflection under wind loading. Just a milimeter of deflection down on earth means huge differences at the satellite 35,000km away. Furthermore, because we built it in Finland, the foundation had to be designed to work with the local frost line... which was not shallow.
It was a heck of a fun project to be a part of.
"Just like a 3rd year engineering student, they can fail if overloaded" I felt that lol
Not sure how I feel about being called out like this as I’m studying for my Vibrations and Acoustics final
@@christopherbrooke2142 Good luck dude! Hope it goes well.
@@christopherbrooke2142 Sending good vibes your way.
Me to and i'm watching this video instead of learning. I got called out so hard
@@kilianortmann9979 Why thank you. Also I appreciate the irony in “good vibes” being short for “good vibrations” lol
Gotta love stress/strain interactions! The demonstration of stepping on the different thicknesses of steel, over alternating colors of sand, really brought back some memories. 30 degrees and Pore Fluid Pressure....
In the early 1980's, I worked for a company that built / installed canopies for gas stations. One customer that had a canopy by a different company, called us to come fix his canopy. It was jumping up and down. You could see the canopy pole actually sliding up and down in the concrete. The base plate was buried in the concrete ( about 2 years old ). So, we jack hammered away some of the concrete and fortunately the easy solution. The installers had NOT tightened the nuts on the anchor bolts. So, we tightened them and poured new concrete. So, it had taken that 2 years for the wind forces to grind away enough of the concrete to achieve enough movement to cause alarm.
or it took two years for the guy to call
@@ThomasSchannelnowadays you’d just be told it’s a feature not a bug
@@AlexofZippo Based on your zero experience working in the trades or doing business with them.
@@AlexofZippo Let me show you it's features
I regularly design base plates for industrial gearboxes, mainly for use in waste water treatment plants. We mainly use stand off designs for that, though some customers prefer a flange mount. This was a great basic summary and I very much enjoyed the video. Always love your content and the scale demos, keep it up!
Clarifier and thickener drives? Ever hear of DBS?
@@joecummings1260 Mixers, aerators, and clarifiers. Our drives may be used for thickeners, but our SAP system can be weirdly limited on application specific selections and our sales guys don't always clarify things further to us... which can often be frustrating and cause us designers to go back to sales for more information. Don't know why they never seem to learn from it either.
Can't say I've heard of DBS Manufacturing until I just Googled it. I work for SEW Eurodrive.
ALWAYS THANK THE GUYS THAT HELP KEEP THE WORLD RUNNING SMOOTHLY,
LIKE YOU DO!!! THANX!!! 🙂
Honest question? Is there a competency crisis emerging in your field? I'm fascinated about this stuff. Lots of fields we take for granted have a lot of old guys and not enough young guys going into it. Curious if this applies to your field too.
@@cendrizzi thankfully it doesn’t seem so. My department has a really good spread of experience and ages. We have 15 engineers/drafter/technicians and we range from ~60yo to just out of college though the ages are heavy in the 30s. In addition, we rotate 2 co-op engineering students on 6 month internships every year with a program with Clemson University and we’ve hired several of them after the fact. I think our field seems to be pretty stable at the moment.
5:51 Fun fact: the concrete design code's section on anchors (ACI318) was SO bad and hard to use, that "Appendix D" became an in-profession meme, where you can compare any calc to Appendix D as a quick gauge of how annoying it would be ("I can do that, but it will be an _Appendix D_ level design"), so much so that when they reworked the code, it was moved from Appendix D all the way into Chapter 17, to help lose that colloquial baggage.
This is the second time I’ve seen the word colloquial in my life and the first time was today as well. Really strange.
@@standout8616colloquial!!!!
@@standout8616 Isn't it funny how that happens? In reality, you've probably seen/heard the word hundreds of times, but now that you KNOW the word, your brain actually _recognizes_ it. Tho, I swear, this happens to me all the time too... Brains are weird, or maybe coincidences are weird. Probably both.
We still call it "Appendix D" regardless of where it exists in the code now.
@@kindlin It's called the Baader-Meinhof phenomenon
Hey! I actually have a real-life use case that goes with one of our videos. I designed and helped build an astronomical observatory. Two concrete piers are located inside a small building with a roll-off roof. Telescopes and their mounts big enough for this project are heavy beasts, and getting them connected, level, and at least somewhat isolated from the concrete piers -- for both vibration separation and moisture coming up from the soil underneath -- led me to use L-shaped stainless steel threaded rod, with thick stainless steel plates and leveling nuts. I didn't have engineering software or the knowledge needed to accurately size the materials needed, so I did what I often do when making something structural: obvious overkill. The scopes are so strongly supported and separated from the concrete piers that you can whack on the piers with a large hammer and not see any movement at the eyepiece of the scope, even at high magnification. (Yeah, I wanted to test this, so I did, just once!)
Ha, I was going to mention this looks like the pier plate of a observatory mounted telescope. :)
I'd love to see a Practical Engineering on big observatories.
It's not obvious overkill, it's designing for deflection limits with large a large Factor of Safety
I had heard on some of the telescopes, the bases are floated on pools of mercury. The mercury provides little friction to turning and it doesn't transmit external ground vibrations well which if you have very sensitive equipment and are taking photographs of objects far off, any little movement can mess them up.
As an amateur astronomer without a permanent observatory for my telescopes (although I know people who have them), I appreciate what you did. I am also a civil engineer who occasionally designs foundations, anchors, and base plates for small signs and light poles. For my last project of this kind (modest-sized light poles at a park, about a year ago), I used the Simpson Strong-Tie Anchor Designer software, which is free. However, if you don't have an engineering background, I suggest getting an engineer to do the calculations, especially if the calculations must be submitted to an agency for permitting.
L-shaped anchor rods are fine for modest loads, but if you get into a situation where anchor loads are high, I suggest hex head and heavy hex head anchor rods.
An ant walks past and my scope wobbles 🙃
As a corrosion engineer, I (almost) missed the ( most important, of course ;) )failure mode of corrosion of the rebars or bolts until I heard a mention at 9:09. Thank you, Grady.
Anchor bolts are a pain to get right even after the design is set. I was the production manager for piers and light pole bases at a precast concrete plant for years, and the thing that demanded all of my focus was the anchor bolts going into them; what's the size, the spacing, how far up do they project, etc. All that information was needed before I could schedule something for production and it's astounding how often contractors placing an order just couldn't give me that info when asked. All the fretting over the bolts was to avoid getting the call that the 20 foundations we built and delivered wouldn't fit the baseplates on site.
Why wouldn’t they just give you baseplate templates and bolts beforehand. It would make “screwing” up the job next to impossible, no?
Wouldn't it be your job to tell them what is needed for YOUR precast products?
I am not getting why a light post wouldn't have the baseplate screws already calculated for. How much do base plates cost compared to say a 1 inch to 1-1/2 for example?
I am just wondering why any of them would even bother for minimum specs. I feel like over engineering it is not an issue. Here everyone gets a 2 inch thick baseplates, and anchors as thick as my wa
@@JetSkiSuper7 Sometimes I'd get a template, sometimes I didn't. I've been given the wrong template before as well. One time I even got a template that was printed at the incorrect scale and so the bolt spacing ended up being too close together. When the information was liable to change hands several times before it got to me, I just had to be diligent in making sure everything was correct.
You got one job man, that's your job😂. It's engineering my man it's supposed to be difficult
@@JetSkiSuper7 We are a sign contractor that has always built (and wants to build) our own anchor bolt forms. Increasingly, the industry is moving to other contractors on site digging the footing, building the cage, pouring the concrete, and placing the bolts... The track record "screwing up" is much closer to 100% than impossible.
Bolts on the wrong centers, bolts are as plumb as crooked teeth, not enough thread above grade for the leveling bolt + plate + clamp bolt. The list goes on.
An alternative to base plates for smaller sign poles and lighting poles are prefabricated foundations with a hole you insert the pole into then use wedges and a cover plate to stabilize it. They're really popular in municipalities here in Sweden as their lifetime often supercedes the poles themselves, lasting 30-60 years. Lookup cetong and meag.
Was that baseplate at 3:50 from the liberty bridge in Pittsburgh??
Some contractors screwed this up in New Zealand earlier this year. They were cleaning the base plates of a transmission line and unscrewed 3 of the nuts, leading to the tower falling over and the whole northern region of the north island losing power for a bit
that's a remarkably bizarre story. What version of "cleaning" involves removing baseplate nuts?
@@davidwilliams9302 Gotta clean the threads that those pesky nuts are occluding. :D
@@davidwilliams9302I'd guess it'd be rust cleaning and repainting? Or there may have been something extra erroneously bolted down.
@@killsode4760 Could be, but do them one at a time for cryin' out loud!
@@davidwilliams9302 Likely cleaning off rust, and instead of doing one at a time, which would mean essentially taking 4 days to do it, assuming they were removing one nut set at a time, spraying with high pressure water to remove rust, then applying a protective first coat, then running the nuts back down and then a second top coating. Instead they undid 2, got half way, then went to undo the third leg, and found out that because of cable sway, and likely the cable direction changing, that the third one meant the side tension from the direction change pulled the entire tower over, as the last one was on the inside edge and thus still under compression, while the other 3 were under tension.
I'm a structural steel fitter/fabricator. Really enjoy it when your videos touch on areas I work with.
Me too, I used to wonder about base plates and why they were set up in different ways. This video was pretty cool from a welder's perspective
I must say this channel has genuinely shifted the way I view our roads, plumbing, and electrical services. The true level these systems must operate at is insane
Engineers can design everything correctly, but what happens onsite as an altogether different story. 😊
@@wilsjane (given the appropriate boundary conditions and funding)
"The true level these systems must operate at is insane" - This is especially true when you realize that many (if not most) of these systems are forced to operate for decades longer than originally designed due to the owners' refusal to update/replace them.
@nomore6167 oh absolutely. And especially when you take into account that there are a lot of mistakes being made everyday on these systems, yet they continue to serve and achieve their goals. Human engineering is amazing
@@nomore6167 Enforce the use of Hi-Vis use by date on the structure, that'll scare the be-jeezus out of most people.
As a structural engineer who mostly watched your videos for the geotechnical side of things, it's rather pleasing you take on a different approach. I appreciate in your way of presenting the general ideas of construction engineering through exaggerated home brewed experiments. I feel like younger generations of structural engineers forget that half of our job (considering our insurance and the liability side of things) is to understand which details require attention and which don't About another 25 percent is through understanding and judging a contractor's capability to carry through with the design. What i love about my job as a sturctural engineer is how it often comes down to seeing things deform in your 3D mental space and never forgetting Hooke. I'd appreciate immensely if you would kept the "practical engineering" side of things and showed structural engineering with heavy foam blocks (simple bending and shear) or spagheti (instability). Regardless always a pleasure your videos are always a pleasure!
Cheers
Hooke's Law, man. I've seen that many engineers, even at my own company, that just don't get it. They think you can put a simple 8x8 DFL wood sleeper across some steel joists and get RIGID load distribution. Hardly. All the load will go on that first joint and the wood will just defect, barely loading up the other joists.
We had an as-built condition that wasn't quit working, so the contractor came back to us, and that engineer had left, so it was up to me to verify the design. As it was already fabricated etc, we really wanted these to work, so I actually did the deflection calcs for the wood and the steel, with different loads going into each thing, and found it wasn't even remotely close to working. Then we had to redesign everything all because our previous engineer forgot about deformation compatibility.
As someone who works in construction and has seen all of this in real life, I appreciate this video a lot!!! You do an excellent job.
11:30 Tuba player here. You get it.
Bass singer here. I felt seen.
@@QDWhite the first and last time
@@MikehMike01 lol😂
LMAO touche 😂😂😂❤
As a bassist I feel a great love for that analogy
Up her in Quebec, most new light poles are now design with standoff base plates to prevent corrosion of the interior surface of the pole. De-icing salts combined with high humidity inside the poles are just chewing up pole otherwise. Including aluminum poles.
Would aluminium poles not suffer from bimetallic corrosion with the steel fixings ?..
@@peterfitzpatrick7032 Normally with aluminium poles the bolts are 316l stainless steel, which suffers less from corrosion with aluminium, especially if you use a anti corrosion inhibitor liberally during installation. by me there are aluminium gantry units that have been up for close to 40 year exposed to salt spray, and aside from being cut down for scrap metal, they are surviving well.
True here on Long Island NY.. salt water marine and road salts .
Rust jacking an issue .
0:59 I am strangely excited about this. After years of watching you and others about infrastructure, it's great seeing an episode on the one singular entity that literally ties everything together in the modern world.
Not quite everything, but quite a lot, especially in the commercial space (where steel construction is common). You'll often find the same anchors in residential construction, just anchoring a sill plate to the stem wall. Or in concrete construction, you just extend the rebar up from the foundation to tie into all the column or wall reinforcement. Any time you do have some large steel member, tho, either a beam or a column, you can expect to find a steel base plate going into concrete.
Good job covering anchors and baseplates. Worth mentioning is also when you have stand off baseplates and shear forces you introduce a moment force in the anchor, and they have almost zero capacity for that. It's a headache to design without grouting - you end up with anchor dimensions that look way too big compared to the plate/construction element.
"Look" too big, but they aren't...
People have no idea how much wind load a light pole or signpost gets, for example.
See my comment about why we haven't a sign foundation calling for grout in the last ten years. It fell out of favor for a reason.
If the exposed height of the anchor bolt beneath the leveling nut is less than the anchor bolt diameter, bending isn't a concern.
@@davidwilliams9302 Now I'm curious, but how do you propose I do that on a video with 1000 comments?
The TIA (Telecommunication Industry Association) structural code, which covers the huge poles that go up like 150-ft and support massive arrays of antennas (and also for guyed towers up to THOUSANDS of feet tall), expressly FORBIDS the use of grout as a compression element, for all the reasons stated in this video. You do end up putting a LOT of bolts that are large diameter.
For example, a 40-in diameter pole might have (30) 1.5-in anchors, or even 2-in diameter anchors if the pole is really tall or has high wind loads -- that's a bolt spacing of only a couple diameters on center.
Ooh, this one brings back an unpleasant memory. Many years ago, in college, I worked on an industrial construction site one summer. One of the assignments I drew was to use a pneumatic tool to scarify the top surfaces of the concrete footings for the process building, so the grout under the vertical columns would adhere better. To keep the dust down, the tool had a water sprayer built into it. I inevitably ended up covered in mud made from pulverized concrete, and within a few hours the lime in the concrete dust disintegrated my shirt and, uh... let's say certain sensitive patches of skin underneath it. Naturally, my foreman found a way _not_ to report the profuse bleeding as a work-related injury...
Throughout my career as an electrician I have installed thousands of pieces that required anchor plates. From light poles to motors and motor control centers to substation systems and fences. Very good video!
"But like third year Engineering students, all those anchors can fail if they're overloaded." 5:25
As a junior in engineering I’m feeling very called out
heh I started going for ceramic materials sci, 3rd year no so good, ended up mechanical testing hvac materials 25 years later. Should have started in mech eng school.
Thank you Grady. I work in fabrication of DOT signage structures. I have been waiting for this very video ever since I found your channel so many years ago. Excellent job and keep up the good work.
How long have you been incarcerated?
@@cruisinguy6024 I hope you don't mean that literally.
Found the nuts get loose, stripped and weak.
@@TheOhDeeEsTee it was a joke because prisoners have historically manufactured transportation items like signs and license plates.
@@cruisinguy6024 lol. No I don't deal with the signs themselves just the support structures. Over my 18 years I've built structures for most of the eastern US.
When I had my RV and mobile home repair business, I got a lot of calls to relevel mobile homes.
The problem usually was that the concrete blocks used as piers sunk into the ground from the weight of the mobile home.
My solution was to install a level 2' x2' 3/4" pressure treated piece of plywood under each pier and reset the concrete blocks the proper way and doubling them as a pier.
The plywood spread out the load and would only sink 1/4"-1/2" rather than half the width of a concrete block.
Having the honor & pleasure of co-authoring dozens of ASTM (I) standards, ❤the channel.
A standards-compliant fan!
I’m from Brazil and I’m a engineer student. Just amazing that right now I am studying steel structures and projecting a base and you make this video in a good time
Also remember that additional plates can be embedded in the concrete as part of the anchor bolt structure. Those can help distribute both compression and tension forces into the concrete footing.
I've never seen this in the sign biz. That sounds like a headache to ensure that concrete completely flowed above and below the captive plate with no voids. Vibrating will help yet 'faith' sees involved. Obviously you know what you're talking about. Just strikes me as odd. What are the applications?
@@davidwilliams9302 you design the reinforcing such that it is a welded cage, and the mounting bolts are a part of this, with welded on L plates that act to spread the load to the reinforcing, and thus allow it to support the load. By me that was done for light poles with caternary cables, which are repurposed century and a half light poles, that originally held tram wiring. he old poles went down to buried concrete blocks that were cast around them 150 odd years ago, when they were removing them they dug down to this layer, and were using cutting torches. I did suggest to the contractor he really needed to go hire a large air compressor, a generator, and a plasma cutter, as that would have made the cutting a 1 minute process per pole, after digging down the meter to get to the base. acetylene torch was taking him around an hour per pole, they are that thick. When they came back they had a standard 8 bolt pattern flange welded on to the base, and had, because of the length, been powder coated, as there is no galvanising bath by me that can handle a 12m long pole, it is 10m long. But the new bases are a 6 cubic meter of concrete, with a rebar cage in them that incorporates the stud base and a secondary alignment ring that was used to bench the concrete fill to. Each base took a full load of concrete to pour to that level, and the base is buried 15cm under the ground level, with another 5cm of pavement tar on top.
@davidwilliams9302 ive installed a bunch and they are usually "X" shaped to hold all 4 anchors together
Correct, and not fun to install when they are in a foundation with lots of rebar.
If you mean the template plate that's only 1/8" or 1/4" thick, that has little structural benefit. However, we also often have 1/2" or 3/4" plates at the ends of anchors (headed anchors), which we d4esign for bending forces and do improve the tension capacities.
I'm a concrete and earthwork contractor, and i love watching these videos. It helps me sell my work, thanks for uploading this!
As a life-long rollercoaster enthusiast, this video answered a lot of questions I´ve had for a long time! Rollercoaster track pieces are often designed with sub-milimeter precision, so I always wondered how they manage to bolt everything together on site with foundations that are not made with that same amount of accuracy.
Consider that much work is farmed out to "lowest-bidder" contractors, and the world becomes a scary place to feel completely at ease ascending a skyscraper or riding a roller coaster. The 1,800+ foot tall CN Tower in Toronto, Canada has an indicator at the top observation level that shows in real time how much the tower is blowing "off-plumb".
In Sept. this year we visited the leaning tower of Pisa, Tuscany and was surprised to learn that some time ago, engineers counter-balanced one side with 200 tons of lead to prevent further tilting.
Having worked in some industrial facilities, another place we use a lot of grout is machinery foundations. The machinery often has to be aligned carefully to connect/ interact with other machines, so leveling nuts on support studs are used. Then grout underneath to support the weight and vibration better.
i WAS JUST THINKING ABOUT CONCRETE !!
I was thinking of galvanized square still. Maybe i need to get off of tiktok 😂
HELL YEAH CONCRETE!!!!! 🌼🌼🌼
Hell yeah, and the great Rome!
Solid choice
I was literally just testing concrete. Lol
Great video. I've worked as a steel detailer for many years and have had to model hundreds of different base plates, but as a detailer you usually don't get the full picture of why a design is the way it is, you mainly follow instructions from an engineer. You learn snippets throughout the years, but this video really presents a complete picture in a way I had loved to have had back when i started my career.
Hi licensed structural engineer here. At 5:03 you showed J bolts/hooked anchor rods. Please know that these have not been used in years and per AISC, hooked anchor rods are not permitted for tension applications. J bolts fail before their full load, due to the hook straightening and also due to a void occurring above the hook from wet setting. A hex headed anchor rod is far superior for cast in place applications
Edit: reading is fundamental. The phrases “have not been used in years” and “we as an industry are trying to move away from them” imply the exact same thing. J bolts are still manufactured and sold and even specced in some cases but that doesn’t justify their use in most applications, especially low/mid/high rises and high wind/seismic applications. There are many types of anchors out there that are far superior in concrete and steel failure modes. Hope this helps
Is this true even for residential applications? I believe I have seen them in use very recently in that setting. They are certainly still sold. Grady's topics aren't limited to any particular genre of construction, are they?
@@tridium-go6hw
It's probably permitted in residential applications. Lots of uses for residential, mail boxes, deck posts, fence posts, all sorts of low-load type applications. Probably not for anything structural tho unless it's a very small load.
I don't know if it's permitted, but a whole lot of residential bottom plates are still being attached to slabs with embedded j-bolts in the Atlanta area.
@WanJae42 we as an industry are trying to move away from them. Screw anchors are a great replacement for wood bottom plates in many cases
We thought these were discontinued as well. But recently had a structural drawing that called for j-bolts to be embedded in the concrete to anchor down industrial pumps. They can be readily found at home Depot.
As concrete carpenter in my twenties I’ve set thousands of bolt settings for structural steel. Getting them correct was one of the more difficult aspects of my job. I had the best luck just having the surveyor double check everything before and after pouring with the total station. This gave me the best overall results, and we’d still be off a half inch here or there.
I am an amateur radio operator. I have six outdoor antennas. They are all either vertical or wire. Some of my friends have the big yagi antenna on top of a tower. My friends with the huge yagis have to take into account for a wind load with the guy wires, foundations and anchor points. Me? My setup honestly doesn't have any wind load, even though I live in Reno, Nevada, which often sees winds coming down the Sierra Nevada mountains at over 50 mph. My favorite antenna is an end fed half wave that is tuned to 40 meters (it honestly works great from 40-10 meters). It is setup as an inverted V. It has survived all kinds of storms. What it didn't survive was when a landscaper dropped a tree on it. But I fixed it with a little solder and some heat shrink.
Over the years I have done allot of light poles and signs. Since the concrete is NEVER level I always use bottom nuts and washers to fix this. I also extend the PVC pipe up to above the wire window so I can grout the base after. I install a dam around the base and strap an air powered vibrator to the pole. I mither grout very thick, relatively so, and let the vibrators distribute the grout. For bigger poles I use a concrete vibrator strapped to the pole which seems to work really well and provide a void free fill. I then use an oscillating saw to cut back the conduits so I can play electrician. Doing these right are time consuming and somewhat expensive. But spelling out the process in great detail has resulted in my bids, though a bit more expensive up front, being accepted over other contractor's. Further, I up size hardware and tie or weld it to the rebar in the base to assure long term durability and excessive strength. Bases are thee most important part of any structure because there is really no practical way to fix sub standard implementations without resorting to heroic and expensive measures. I am just a dumb electrician but I put in a boat load of thought and effort to assure that my outdoor work is safe and out lives me.
I'm a structural engineer from Belgium and I'd just like to say, I really appreciate the videos on this channel. They're at the same time really approachable for people who don't know anything about the subject, while still giving interesting insights for someone with my level of education. Keep up the good work, videos like this really make my day
I worked at a plant that recycled lead acid batteries so the place was always being rebuilt especially when loaders or forklift hits columns. When we would replace or repair these things the plate would be bolted down with 3/4 inch stainless wedge anchors then lift the roof 1/2 inch or so slip in new column and weld the two Parts together. This worked very well as long as there's not more than 2 levels
As a foundation worker turned engineer, I wish this stuff existed 20 years ago. Thank you for helping explain both of my careers with a one-stop UA-cam adventure.
You timed this one perfectly Grady! I'm designing baseplates at the moment for an experiment at my work!
It's for a rain simulator boom arm, that's going to be suspended from trucks running along a pair of goal posts with rails mounted on the top, allowing it to be repositioned for different experiments and to allow access for maintenance of the spray nozzles.
It'll end up looking a little like a gantry crane you might find at a dockyard.
The experiment itself is an indoor compound slope setup for testing different sustainable green drainage systems.
I'm a lab technician in a built environment school at a university in Scotland, but my background in physics and hydraulics, so I'm a little out of my depth for some of these calculations. Learning a lot as I go.
Don't worry though! I'm running everything past a proper civil engineer as well! Not ordering or cutting any metal until I can show my work to the class! 😅
Total suspended load will only be in the order of couple of hundred kilos. Still scary if it goes wrong mind!
Being in the industrial concrete and communication tower construction business I really appreciated this video. Using stronger concrete and anchor bolts and doing away with grout was a great move in the industries.
I just made a whole post discussing this. In the more recent TIA codes they expressly forbid grout as a compression element. But I've had to justify existing monopoles or guyed towers assuming the grout was working in compression (it was a valid design then, but not now). I did have photos to see the grout looked fine, but yeah, this definitely impacts the anchor design, making the anchors work at about 350% demand (mostly due to bending) when you suddenly are just supposed to ignore the grout lol.
Same thing in the utility and power industry for substation construction. Non-grouted BPs are so much better. I've seen SO many structures that have rotting base connections because the moisture and water over the years has been trapped inside of the shaft with no escape because of the grout pad.
@@DirtyD07wait, grout like bathroom grout? That stuff barely holds up in domestic settings, they were using it to hold up poles?
Edit: the video reached that part. Huh.
@ no, cementitious grout, as he describes in the video. Basically just Portland cement with sand and no aggregate.
I'm retired now, but worked most of my career in engineering at refineries and petrochemical plants. Base plates for motors, gearboxes, compressors and pumps used epoxy grouts. Very robust, waterproof, void free, etc. Used on anything from 1hp injection pumps to 12,000hp compressors.
Thanks!
Back in the mid 80’s I invented the Immured Foundation to attach electrical transmission poles to drilled pier foundations and eliminate the baseplate and anchor bolts. The pier reinforcing steel was left extending above the pier and the concrete set. The pole was set over the extended reinforcing steel and concrete placed inside the pole over the top of the rebar. The length was the greater of 1.5 times the pole diameter or the development length. 10 to 15’ was common for these poles.
The problem with anchor bolts has been around for a long time and I have seen a lot of mistakes made and fixed a lot of them. Most are self inflected by the original design engineer.
The Immured Foundation was invented to eliminated the anchor bolts for large steel poles. If you Google “Immured Foundation patent” you will find the details. It does take special software to design.
Is this Mark, or Gordon?
@ Mark, Gordon French passed away.
That seems to just be an embedded pole. Dig hole, plop in the base pole and a rebar cage, fill to grade, add new pole section, add more concrete. The images didn't help me at all, unfortunately, but it sounded like you're just constructing a grouted pole. I'm sure I'm missing something.
@@kindlin Direct embedment works for the steel LD poles. You do have groundline and inside corrosion issues making it unreliable for major poles and they lacked the strength for angles and dead-ends. You also need a larger diameter and burry a lot of steel. LD poles are a replacement for wood poles.
The Immured Foundation was invented for an odd reason and proved to have other advantages. It does not make sense for every application. The Immured Foundation was invented to reduce the drilled pier diameter. A new group of poles was developed that required an auger lager than 10’. The 10’ was the limit of the company’s equipment and to go lager ment a new larger crane drill rig and augers or contracting the project out. The crews also hated dealing with 42-2.25”x13’ anchor bolts. When an anchor bolt was bad, it ment the bolt was cut off and the pole capacity derated.
Prior, we had tried just embedding the bottom section partially in the pier. This installation went poorly. The pole was embedded partially in the pier. This ment the pole had water drainage issues and subject to filling with water. Also it had a larger diameter than the Immured Foundation. The pole base had to be supported by a crane overnight for the concrete to set. This arrangement way bad because it was subject to weather and breakdowns and security and safety issues. Additionally, the crane was not working on drilling holes. This would mean a second crane just to hold the bottom section. The Immured Foundation solved all these issues plus eliminated the pesky anchor bolt issues. The pole manufactures were kept in the dark on the first project about how they were being installed. Once they found out they loved it because they got rid of the anchor bolts and baseplate problems.
The only way to tell the difference between a direct embedded pole and an Immured Foundation by looking is the Immured Foundation has drain holes about 10’ above ground.
@@TexasEngineer All of that makes sense, thank you. But I'm not much closer to understanding the difference between an Immured Foundation and a standard embedded pole. Is it that you extend the concrete up past grade to alleviate drainage issues? It's not too uncommon to fully grout steel tube columns/poles for structural purposes, which sounds kinda like the bottom 10-ft above grade, but it sounds like this was done for maintenance and construability reasons.
Another example where you can see development over time of baseplates is railway electrification, at least in my area.
The older type was coated steel or reinforced concrete poles, sunk into a hole in the concrete bases, which were then backfilled with more concrete and covered in tar to keep out the moisture. The newer types use galvanised steel poles bolted onto standoff foundations. I took a train regularly where this was visible quite clearly when a branch line, which was electrified recently, merged with a mainline, which had been electrified for decades. The old mainline supports used the type sunk into concrete, while the new branch line supports were bolted onto standoffs.
They recently relaid some track on that site, straightening some points and requiring the power infra to be replaced, so now the difference has disappeared, but there are probably still places elsewhere where the difference is visible if you know what to look for.
As a structural steel fabricator and welding inspector, I work with all types of baseplates everyday. I have seen some pretty interesting designs over the years from you engineers 😂
As an iron worker. My job is to install those columns.
I often need to torch cut, re-weld, or make adjustments to base plates and columns.
This was a neat video
There's some serious engineering behind base plates like this, especially for wind turbines. One of the case studies we went over in college was wind turbine foundation bolts. In this case they were installed with leveling nuts so instead of behaving like a typical bolted joint which experiences effectively zero fatigue unless the clamp force is exceeded, the bolts were experiencing fully reversing compressive and tensile loads. Thankfully I believe it was caught in inspection (they retention/torque turbines as part of annual maintenance).
*retension
The elephant in the room!!!!! Unfortunately, while stand off base plates are very convenient for aligning, they do contain a fatal life limiting flaw as @JamesSeedorf has very correctly identified. The flaw is not considered by design standards or by designers. i.e. The thread below the levelling nut. Stand off base plates are the only common situation when cyclic reversing loads are applied to un-preloaded threads. Even ignoring bending, the stress range in the un-preloaded threaded section of holding down bolt is a small fraction of the endurance limit of the bolt material. (The zero bending is a myth because concrete is not a theoretical anchor). You don't believe me? I would challenge you a) To calculate the load carried by each bolt. esp. in a 10 bolt base plate. You cannot. The individual bolt load could be anything, some bolts could even be under net tension due to dead weight only! Why ? The load is dependent on the installer. b) To calculate the fatigue life of base plate assuming that the bolts are carrying a theoretically equal load distribution. This design has been subject to many research papers. For some reason, the stand off base plate design is still permitted. Particularly, for high mast light poles in windy areas. If you do not want to do the fatigue calculation, think of this example. Would you drive a car if its wheels had been "widened" (tracking increased) by adding nuts on the inside of the hub to longer studs? In effect, turning the stand off based plates by 90 deg and then applying reversing loads.
Kilo-grady's made me giggle
I second the nomination of the KiloGrady as the new dimension for UA-cam science experiments!!!
I prefer inverse femto-gradies.
My new favorite unit of measurement
1 grady = 1.0001 newton
I’ve done a lot of steel columns w/base plates, leveling nuts and non-shrink grout. Once I noticed my grouting crew mixing the grout much more soupy than I preferred to see and definitely with more water than was spec’d on the mixing directions was being used. It was almost the consistency of crème of tomato soup. To give myself some assurance that things were ok, I had them mix a batch for some test cylinders with the grout, at the same consistency. When we broke them at 28 days, they had indeed lost some of the prescribed strength. Instead of breaking at 8K-9K psi, like the product spec, we were getting around 7500 psi. I felt good about these results because the steel columns were sitting on foundation pads of 4K psi. I like the idea of getting full bearing coverage of the base plate w/the soupy mix as opposed to using the dry packing method where you can never be sure that you’re really getting full coverage and told the guys to carry on with the wet mix.
I feel recognized as a bassist. Thank you Grady! This was a great video, and I'll definitely be looking out for these when I'm stuck in traffic.
Ditto! When I first started playing, I listened to a lot of songs with the bass track removed which really impressed how integral bass was to the foundation and feel of a song - without it, everything feels flat.
Bonus relevant joke: How can you use a bassist tell if a baseplate is level? Have us stand on it and see if the drool comes out of *both* sides of our mouths!
Crazy this vid came across my feed. I have wondered about this exact topic for a couple of years now. Never looked into it, but just an idle wonder. Specifically the gap between the base plate and the concrete for large signs and light posts. Hearing your explanation makes perfect sense that it is simply a matter of efficiency, once a thicker baseplate and heftier anchor bolts are specified. I suspected it had to do with movement allowance at the base and cracking concrete, etc., and I suppose if that’s all it was it would be better to use a hard rubber gasket of some sort between the plate and the concrete. Anyway, thanks for taking the time to explain this to us non-engineers!
I really like the touch that your book, Engineering in Plain Sight, is right there behind you, in plain sight
I spent years designing structures with base plates and writing design guides for them. This is a really good explanation of how they work. Thank you.
I've definitely wondered about stand-off baseplates before because at first glance it looks unfinished or unideal. Thanks for the explanation!
I work in drafting design for gates and fences. I design around baseplates all the time. we mainly use standoff for adjustability. I never payed any mind to baseplates before I got this job. thanks for this video! super interesting to think about even more than I already do.
Same idea, but the ones you work with are not structural, so their design and use differs.
Concrete finisher is wearing base plates on his feet to spread out his weight 6:34
Snowshoes are just base plates you put on your feet so you can walk over snow without breaking the surface.
Excellent observation !!!!! 🎉🎉🎉🎉🎉
I watch a lot of your videos and try to like as many as I can remember to. But your mentioning of different abstract units like "kilogradies" reminded me why I love your videos.
I'm in structural test for large aerospace structures. When we attach a steel base structure to a concrete "floor" of our test stand we level the base about 1" above the concrete and use a 2-part epoxy grout to fill the space between. High-strength steel studs that were previously threaded into permanent anchors in the floor are then used to pull the base hard against the epoxy grout after it has cured.
Smart, makes sure grout/concrete are in compression and steel is in tension, both doing what they're best at
hopefully the part of those steel studs that are in the grout are sleeved so they pull the plate to the floor, and let the grout section stretch to provide the load. There have been one or two instances of post stressed members not being free to move, which has resulted in the actual substrate failing near the ends, because the tensile members were too firmly bonded to them while the middle was under no tension.
@SeanBZA yes we use foam donuts around the studs (they seal against the bottom of the steel and the concrete) to prevent the grout from getting the stud threads
In NZ, work has been done to make roadside signs friable/frangible. These are designed to collapse into harmless pieces on impact. These can often be simply reassembled. With traffic, this fail safe mode can be directional, check out ILS antenna at airports.
2:08 - I find most materials lack of faith disturbing
The original machine had a base plate of pre-famulated amulite surmounted by a malleable logarithmic casing in such a way that the two spurving bearings were in a direct line with the panametric fan.
Spread the load. This is also important for freight, especially aircraft, as the limiting factor is often the cargo floor and you spread the load with either a pallet or shoring, often just wood planks that allow you to load objects with very small contact points on an aircraft cargo floor that is remarkably thin, and thus light.
Yes, I was tasked to do a pre major overhaul weighing of a helicopter, and this was 45kg over the last recorded weight, simply due to the floor of the helicopter being now almost entirely constructed of Araldite epoxy. the issue was that using it as a gunship, with a 20mm or 16mm cannon in the side, essentially used to tear all the mounts, both for the cannon, and the pilots, out of the honeycomb floor. So they would simply place an aluminium plate under, temporary bolted to the "good" floor, then pour in epoxy (5l cans, none of this little tube stuff) and have the mounts held in position till it cured 24 hours later. Remove bolts and fill the holes with 5 minute epoxy. Then spray with black enamel, sprinkle a heavy coat of dry sand on top, and leave for 15 minutes, then brush off excess sand, and paint again with the black enamel. Might last 2 missions, or 500 rounds, before it ripped out again. basically the entire floor was a solid epoxy block, with lots of plates under it to act where the patches were. Entire floor was replaced with new honeycomb material.
Shoring and leveling of loads is also key with containerized freight. Not only for the aircraft load but in general handling of the container. Too much weight in one spot and the container is far harder to handle and push around, wanting to pivot at the heavy load point.
I was part of the team that assembled the concrete-imbedded bolts for a roller coaster at a major theme park, and part of the design actually included an integrated "top" to form the concrete where the base of the columns would eventually sit. Quite a fun project, actually.
The specs for alot of those nuts that hold the post onto the baseplates are "snug tight" or you tighten them until they break away on purpose
This explains so much of the structural instability issues I ran into with my early work with Linoln Log towers. Knowing this could have saved the lives of literally tens of plastic army men. Rest in piece, flamethrower guy (and the poor grunts standing next to him).
Gotta show this to my friends playing Satisfactory plopping everything directly onto the ground willy-nilly.
Ground? We build in the sky! The ground isn’t level enough 😂
I’d love to see the overlap between Satisfactory players and viewers of this channel
@@FuncleChuck so true, skybridge for the win
@@KyleRichter23 ::raises hand::
For 33 years I've always been interested in them and always found myself wondering how these worked. I really appreciate you making this really specific content :)
I'm in my 3rd year and just yesterday I took a picture of a baseplate on my way home to go and detail in CAD for practice
So this is just going to make me wanna practice more.
Don't you go failing like an overloaded anchor! 😅
Baseplate detailing is a great start to drafting. Repetition is key to getting the hole dimensions and sizes, thickness of plate and any other engineer specific requirements just perfect.
Good luck!
(Senior design draftsman 25+ years)
What country or school are you in?
Love this! We always manufacture our posts intentionally 25mm too short and supply "packers" to make up the length, the packers are 100mm square and you can plumb the columns around them with the nuts on the anchor rods (obviously only after the chemical fixing has cured). This also helps to keep the anchors in tension so the main loading through the post bears nicely on the "5 star - non compressible grout" between the baseplate and the footing.
Now consider what the ancient builders had to deal with, where the columns just had to sit there with no bolts
I’ve noticed them my entire life but never really paid attention to them. Thanks for explaining the engineering behind them Grady 🤜🏻 you’re one of a handful of UA-camrs that I watch their videos as soon as they come out
Of COURSE you used a picture of Vancouver when you needed to illustrate "moisture" at 9:06... 😂
.....and dog urine adds "moisture" that gets added to those baseplates....
@@-Cece "dog" 🤣🤣🤣
Lol. I literally opened my phone so I could add a comment about seeing my city in one of these videos finally...
Yup looks like a typical day in Vancouver! I believe we’re looking up the hill on Burrard near the station, my morning commute to my first job as an engineer 😅
as another Vancouverite, I came to the comments to say exactly this 😅
I'm so glad I found your channel, your explain the dynamics of engineering in an incredible way for someone like myself with no engineering background, but love doing DIY - Thanks!
Literally *BASED* 😎
5:30 When putting the anchors in the wet cement a cage of rebar around the anchors can prevent any problems with cracking. And it is relatively simple to bolt them to a stabilizer attached to the form so they stay in the correct place.
I wish what you wrote is the industry standard.
Yes, adding rebar all around anchors helps a lot, it basically precludes all the failures except steel yielding and bond shearing, but I mostly work in existing construction, where we are post-installing anchors with no control over the existing rebar, and can, at most, say that there is a side bar to prevent concrete breakout.
as a bassist i loved that bass guitar analogy you made. made me smile :)
7:27 deez nuts
Thank you, this saves me from having to write that
I HEARD IT TOO lolllll
Thoroughly appreciate your content. I work construction. This week I was building concrete bleachers for a baseball field. I can follow instructions, but the practical physics are nice to understand.
I built a 75 foot long tilt over radio tower for my antenna's. I am no engineer, so I over built it. 3 yards of concrete, over 300 feet of rebar in the base, 12 -5/8 anchor bolts cast in place, and all leveled with nuts. I have 1000 pounds of steel in the self made hinge base and truss system to lower the tower. It didn't break, at least not yet.
I'm laughing because obviously a straight antenna doesn't have the wind load or leverage of a big square sign, but "3 yards of concrete" and "75 feet tall" in the same sentence is giving me the sweats!
@@davidwilliams9302 Its a Rohn 25G tower and has 2 sets of guy wires. The base plate is 3 feet by 5 feet 1/2 inch steel plate. She be rugged.
I wonder if I saw you post this same thing years ago. I don't remember which video or channel, but I recall a very similar comment. With a guyed tower, the base foundation just needs to be wider to support the extra down-force froim the guy wires, it shouldn't need much in the way of depth or anything like that. I would expect probably a 6'x6' by 2' deep foundation for a 75-tall guyed tower, just bearing below the frost depth basically.
Now, the guy anchors on the other hands, those are the really hard things to design. You often need massive concrete deep underground to give you enough weight to resist huge loads from, like, 1000+ ft tall towers.
@@kindlin Our frost goes down 4 feet. The cement is a touch over 3 feet wide, 5 feet long, and 5 feet deep. Its so big because it supports the tower as its lowered. The lowering truss is 20 feet high where the winch pulls from so the torque load is high. My guy's have 300 pounds each of pre load.
@@1958johndeere620 Oh, ok. I'm not familiar with collapsible towers, there must be another tower somewhere that lifts up a guy wire or something to pull the tower up? Or is there a giant motor to torque the tower up, just from the foundation? And out of curiosity, what size guys do you have on that? 3/16? 1/4? At 3/16, the 300# would be just about standard spec (10% BS).
It's a gift to feel more informed after a video on YT! Thank you Grady. (Hope your family has a wonderful holiday season filled with joy and connection--and starved of overly crass commercialism.)
As a bass player I appreciate the analogy to bass lines and its foundation properties. It makes me love your channel even more!
I normally build a ground cage that is set into the concrete with the threaded studs pre positioned.
The base plate and post is floated on nuts underneath like examples shown in the video. I prefer this as the structures level can be easily adjusted.
If / when you’re up for it, would love to see more videos on disasters and preparedness (especially regarding the grid) - maybe home generators? No worries if that’s not the direction you want to take your channel. Thanks for the consideration.
Thank you Grady for consistent quality content! I built my garden observatory (a garden house with a roof that can be completely rolled off) on multiple H-anchors set in point foundations of steel and concrete. My goal was to get the wooden pillars away from the moisture of the dirt underneath. That seems to work great so far, but I never found reliable data on how much weight in compression forces I can actually safely put on these anchors.
Base plates are cool. They distribute vertical load onto a footing. Spread it out evenly.
Thanks great info! Will be putting up car port with some sort of base plate arrangement. On a previous project helped design a moment frame to resist racking. Base plate with L bolts and grout was initially spec'ed, but to save steps/time/cost and increase pullout strength, changed design to sink base plate into the concrete while still using L bolts. With one concrete pour, a portion of column, base plate with L bolts attached were all buried/surrounded in concrete. The column was suspended from other existing structure elements during pour and while concrete was setting. Unique problem with unique simplified solution!
if a baseplate is like a shoe, are standoff baseplates like high heels?
They're more like platforms maybe?
as in platform shoes
@@alephkasai9384 I feel like the ones with grout are more like platform shoes! Because they've got that platform thing going on.
I think you'd call them geta (a type of Japanese shoe).
When I was in college, there were many octagonal type poles on the way for overhead higj tension power lines.
I always remained confused why the poles are 2 to 3 in higher than the concrete foundation below.
Ultimately I started my bachelors in Civil Engineering to find this specific answer, and in my third year during the first lecture of steel structures I finally asked tjis question from my steel structures teacher and got the answer.
After that, base plate and anchor bolt design became my favourite.
1:40 pirate-ninjas for sure :)
Martian reference?
Awww yeah my watney man
Working in heavy civil construction for almost a decade, a really large number of light poles along the highway are actually designed and installed with “transformer” bases that are made from a softer aluminum that will tear and break away in the event of a collision. Also, the bolt “holes” are actually slots that are open ended to assist in the break away function. Lastly, due to the overall height of most of them, even if they are hit they usually don’t land on the vehicle that hit them. That vehicle passes more or less safely under the pole and stops outside of the fall zone, kind of like kicking out the bottom of a baseball bat balancing on one end.
Having been the guy who, A) set anchor bolts in wet concrete, B) rough designed pre-engineered steel buildings for quotes, and included building forces to contractors so they could also quote the necessary concrete anchors in their bids, and C) having been an assistant foreman, meaning *I* was the guy who had to *FIX* anchor bolts set in the wrong place, and also had to grout under base plates...I'm invested in this video, even though I'm now retired 😂
Good presentation, as usual. You do a good job of presenting a substantive summary while making obvious the true complexity of the subject at hand. I lost track of the number of times I was told to "just design the base plate", without being given a spec for the loadings, the base materials and the conditions of use.
Base plates are like the snowshoes of engineering.
Thanks
7:30 Adjust THESE nuts! Sorry, someone had to say it.
Bofa Dem Nuts
I have ***always*** wondered about the stand-off base-plates I see on the side of the highway. "No way is that more secure than just bolting it to the ground..." I would always think to myself as a kid. You can only imagine how excited I was to see this video in my feed! 😄