@cometcatcher5
As a telecom structural engineering professional, I see these literally every day on multiple analyses a day and this is the most succinct way I've ever see it explained. Stealing this to train my new hires! Keep up the great work Grady!
@DTXBrian
That head shake at the end, though. 😂 Sincerely, I appreciate and eagerly anticipate your videos. Thank you for your hard work in each and all.
@nomadben
I worked briefly building radio towers, and we would anchor them this way. Thread the nuts on to the studs, level all of the nuts to each other, set the tower leg on top, then another set of nuts on top to anchor it down. They would always be floating with no grout or filler in between.
@saab9251
Large industrial pump R&D designer here, we use these anchors for essentially every single installation along with a requirement for 1.5-2” of grout. This is pretty much industry standard. We also require the customer to fill the entire pump base with grout in addition to the 1.5” gap between the base and concrete slab. This is largely to pass seismic requirements in certain districts and to absorb unwanted vibrations.
@MJ-sm1up
Always thought it was crazy that all that weight is being held by the threads of the bolts
@Ash_G
I watch this channel to increase my civil engineering vocabulary so I don't sound like a noob when contracting something. Thank you and keep them videos coming.
@leroyjenkins2051
I work in construction... i see this all the time in the field and when reviewing shop drawings before submission to the arch to SE for review and comment.. well explained and in simple temrs for all understand (unlike most SE).
@markfryer9880
In 1984 as a First Year Apprentice Carpenter, I helped install at least five large buildings worth of these Holding Down Bolts and most of them were sunken into the concrete slab to be concreted level with the finished slab. Each building had a HDB plan and a coding system for the type and size of each Base Plate. On another A2 page was the detailed drawing of each of the different types of HDB sets that needed to be installed along with the depth of the boxing required and also the location of the Grid Lines in relation to the bolt cages. There was also a further plan detailing the number and size of the extra reinforcing bars that had to be installed in order to link the HDB cages into the steel reinforcing for the concrete slab. I certainly learnt a hell of a lot about installing HDBs and getting the grid location right as well as the Datum Height. It all came to a head one day in Third Year when I was working on a 6 Storey Commercial building. The Structure Foreman Frank called me into the Site Office and as I was the only Carpenter from our Company on the job site that day, he tasked me with going up to the top deck to install a set of HDB's for the Plant Room Structure. No problem! I knew which plans to refer to for the type of bolt cage and any offset required from the setout grids. I made a quick HDB plate with grid marks sawn in, grabbed the bolt cutters and some lengths of reo bar, tie wire, tie wire nippers and some string lines. I went up to the Top Deck and spent the next couple of hours installing the HDB cage and plate. I wired in the extra reo, and then set the plate and the correct location for the grid lines and the correct FFL (Finished Floor Level). Satisfied that everything was spot on, I packed up and then went back to the Site Office to sign my initials on the plans for that set. I then forgot about that job until a couple of weeks later when the Leading Hand asked me at Morning Tea if I remembered doing such and such set of HDB's? I said that it sounds about right. Why? Because they were the only set of HDB's that didn't require blowing by the Structural Steel Riggers installing the Plant Room. Blowing refers to the use of the Oxy/Acetylene gas axe to cut a larger hole to fit the base plate over the HDB's. There was probably at least a dozen HDB's for that structure and it would appear that my work mates of a Leading Hand, a Carpenter and two other Apprentice Carpenters the year below me, were not as experienced in the installation of HDB's. This was a fairly simple structure that didn't require any fancy size changes or grid off sets, so it pays to get to know your plans and detailed drawings. Other people have been caught out with HDB's and steel work, measuring from different points and not allowing for measurements from plate centre vs edge of plate. That required eight 25 mm holes to be drilled into two head beams for hanging the new school brass bells up on top of the Clock Tower. When the error was discovered and it turned out to be the size of the base plate, I knew that it was as a result of measuring from different points, outside of plate to inside of plate and not detailing the sketch notes carefully enough. Fortunately the head beam was over length, so we just measured from the centre of the holes in the head beam and went outboard half the width of the base plate, drilled the holes top and bottom of the hollow beam, cleaned them up and we were ready to install them the next day without any problems. Mark from Melbourne Australia
@TheCursedHonestTruth
The best part is when he said what the infrastructure was that he was vaguely referring to.
@Bremend
Huh I thought you were going to talk about how some signs are designed to be broken in case a vehicle crashes into them
@mrgallbladder
Literally last week I was in a pool and thought it was interesting that their pillars for the waterslide had floating base plates. Figured it was for level adjustment. Turns out I was right.
@chrysshart
That is fascinating. We really underestimate how strong bolts are, eh?
@skully70
I'm an engineer, i understand all the science and reasoning, and there is still something about this that causes my brain to short circuit!
@devo1977s
I find it interesting how highway signs used to be set up with normal anchor plates but then they found out that was bad 🙁 in many ways and now use a break away system
@DavidPfeiffer-s6z
Great explanation of the problem with the non-leveled surface of the concrete base plate. But I believe that the real reason for the metal plate floating above the concrete surface is another. when the nuts are tightened, only tensile stresses are applied to the metal plate. in this configuration, the base plate only absorbs compressive stresses. If this were not the case and the metal plate were to rest flat on the concrete slab, the latter would have to absorb tensile stresses and, due to the low load-bearing capacity against tensile stresses of concrete, the threaded rod would break out.
@geneard639
Some baseplates hide the kerf in the bolts that allow them to fail if a car or truck hits them. It reduces damage to the structure, and lessens impact forces on the vehical and occupants reducing injuries and fatalities.
@jonathonwiedmer5701
Another thing is many traffic lights and light poles, are meant to break when a car/truck hits it. This is done to absorb much of the impact, to protect drivers from even worse accidents
@LotharTChips
As a steel worker I can confirm. If a project is every dependent on concrete being level, it’s not. Either stand-offs or you measure the set concrete.
@arlenhartoonian305
Wow!!! I was always unsure of the logic behind these baseplate details. Perfectly explained. Thank you!
@kayzeaza