Concrete requirements for a 2 post lift.
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- เผยแพร่เมื่อ 5 ต.ค. 2024
- We had to take out some concrete in an auto body shop that was not thick enough to support a automotive 2 post lift. We poured some new concrete at the proper thickness that was required by the manufacturer.
As a former distributor/installer of lifts there should have been a continuous pad poured from post to post 2 foot past post on each side and minimum 6 inches deep with pinning and 4000 lb or better concrete. The lifts should not be installed in less then 2 weeks after the pour. I have seen what happens if this is not followed installing overhead or non coupled 2 post lifts.
Now that sounds right. I recently watched another video where the guy was using eight inch long Sampson wedge anchors on a residential poured concrete floor. He was complaining that he has to keep tightening the anchors.
He came to the conclusion that wedge anchors suck and was moving on to epoxy type anchors. His comment section was very entertaining.
Do you think just leaving the slab the way it was is better than cutting out squares which now makes a weak point? Unless your doing it the way you said I feel like leaving it how it was would've been stronger.
@@tanthony298 , both are dangerous.
The commentator knows more about it than I do but when you consider the weight and the hight on two legs.
The single pour is so the legs don’t move independently. Personally I would go at least a foot down and bell the hole for a wider footprint. That way the mass has to move a lot of earth to shift.
Cutting the floor is easy , digging the footing is easy and concrete is relatively cheap
Think about lifting a car you pulled the engine on and it has a full tank of gas. Then you start breaking nuts loose on an unbalanced load.
If you’re lucky , you don’t get hurt , but you’re definitely going to break stuff.
Yeah, they just wasted their time doing what they did in this video. It's still dangerously inadequate! Should've cut out for one solid slab, and dug down AT LEAST 6 to 8 inches further, and dug out under the uncut part of the slab to make the new pour key in underneath it as well.
Do you have a link for requirements I can read? I'm looking to put one in my shop soon. Thanks for your comment.
I had my garage poured 5” thick with fibers and wire mesh. The building is 30’x30’. I bolted my 2 post to it with wedge anchors. Been there for 10 years now with daily use. I periodically check the nuts to see if they have loosened up. They never have.
Mine loosened a little bit for the first 6 months then they found home.
I was watching this video and then my neighbour came and we watched it together. He said that this video changed his life and touched his heart. I then went and rented a projector in a big field and all my villagers watched it and it changed their lives too. We all are so grateful.
Thank you for this video!
I was there. It changed my life. Not to be a negative nelly but maybe next time an intermission or maybe a porta potty would be nice. Until then keep changing lives.
Why didn't you dig under the slab a few inches so the new concrete would be pinned under the slab making it 10 times stronger?
Exactly undercut and re-bar
I did 4x4 1.5’ deep pads. Compacted 6” gravel with lime dust. I have 12” of concrete. I made a jig of the bolt pattern of the lifts base. Welded them to an 1” thick plate. Welded 4 rebar posts on bottom of plate and positioned in concrete, leveled and aligned with opposite side. One side has one mounting position and other side has 2.Mini Cooper width and F 150 width. I epoxied rebar into original concrete, 3 per side and welded them to the mounting tubes. Didn’t want the tubes moving. I used 5009 psi concrete. A week after concrete was poured I lopped off tubing to concrete level.
Overkill ? I think not. I work on my stuff by myself. So no.
It’s a lot of work!
Building an airliner runway? Ho Lee Fuk
@@seanmurphy2302
LOL. Taking no chances. Work on my stuff by myself. I think of the weak areas and over build. My chit don’t break.
@@Nnonyabiz
Lol 😂
Bendpak recommends 12" rebar reinforced concrete for a 2 post lift on 4x4 pads. we are doing the same thing here hopefully ready to install lift by april 10th.
@@dawna2619
I didn’t know that! Wow. What’s the chance of doing exactly what the recommended. I’m serious. I didn’t know.
Can’t remember if I mentioned, I made two mounting positions on driver side. Mini Cooper width and pickup truck width.
I had a tacobell ad right before the mud came down the chute 🤔 lol
LOL thats funny.
Lmao
My daughter works for Taco Bell. A shute clearing experience at least once week for sure. 😂
Same here
Some people need to read the install manual. 4’x4’x6” @ 3,000psi is what the manual for Rotory SPO10 when the concrete isn’t at least 4 1/2” deep for the Hilti 3/4x5 1/2 anchors.
What?! I used to work at that shop...in that building! I was working there at this time. I left a few weeks after the lifts were installed. Small world man! Just came across your videos the other day. Didn't realize you were in this area.
Also, excellent job.
LOL small world for sure.
Back when I installed my 2 post A frame lifts, I was told the concrete needed to be a minimum of 4" thick. My floor is roughly 6-8" thick and I havent had any problems in the last 10+ years they've been installed. I might add that my floor is just a floating slab on concrete. It's an old barn that was never intended to be used as a work shop. It was just meant to dry grain in the winter. Like I said, Ive had no problems. I'm sure this qill be perfectly fine, despite the arm chair engineers critiquing your work. I think you guys did a good job.
and you never will. 👍
Huhn? Hate engineers? Six to eight inches is clearly greater than four. Hate mathematicians too? 🙄
Some folk are engineers; however, I seriously doubt any professional engineers (PE, licensed) would comment because of liability. I'm definitely not a civil engineer but had to take their weed-out class of statics.
Yup! More than doubled the thickness, tied in to existing floor with mesh and 12 pieces of bar per hole, those lifts aren't going anywhere!
Thanks. @@ronlovell5374
i worked under a car lift for years, then they replaced the lift. It was on 2" of concrete and the bolts were holding nothing but sand.
Yikes this scary
This guy could have done the same.
Good lord
We have installed 1,000s of lifts. This is NOT how to do it. Pad should be 15 feet, left to right wide and 5 feet front to back and least 6 inches thick of 4000 PSI. It should CURE 30 days before installing the lift. Pinning to the sides is a good idea, but the wire mesh is a bad idea. Now we don't know much but we have been doing this since 1987.
Tell that to Mazda Thousand Oaks for me
How far from the edge in your opinion? I was hoping to be about 12" from the edge where the foundation is
Think I'd have done all 4 had it been my shop just to be on the safe side.
😢 video cut short - I want to see more 😭
yeah great job on the cuts and rebar, but since they're there, i would've unbolted that 1 column and just had them do all 4. have serious doubts that one column already anchored is better than what these guys are doing. sure it cost more, but so what pay them (they're worth it).
I honestly think keeping an original slab all in one piece that's 4" or so thick with wire and rebar is stronger than cutting out a square and just to make it 5-6" and now you have a square that isn't bonded as good as the original slab I could be wrong but it seems right.
Its more about how much thickness to hold the bolts to the floor than a strength problem.
Put a bonding agent on the old slab on all 4 sides and the new concrete will bond to it.
They make lots of bolts that set in less than 4” of concrete.
He doweled it in. No need for bonding. @@GoatzombieBubba
You are partially correct. However , the thickness affect the ability of the bolts to grab and hold. These will give way before the concrete crumbles are cracks.
Hardly even went any deeper. 🤣 Coulda took out everything in between and given it some more heft. With the short load anyways may as well get the extra concrete and put it to work.
I was thinking the same, he just dug up what was there and replaced it with same thickness
Thanks for the info. Just what I needed. Good job
No problem.
I found this same issue in my shop (existing when we bought the house, built in 70s) when I went to install a lift. I reached out to a buddy who is a mechanical engineer for a civil engineering firm who build bridges and suspended concrete including post tension pre-fab. My slab got cut in a 3 ft wide path in the shape of an "H" with lift posts at the intersections. Original slab was 4.5-5." thick but light on rebar/mesh, unknown PSI rating. Dug down to 18", compacted virgin dirt, then 3" road base compacted then 3" sand. Rebar cages at the post bases but outside the bolt radius and below 7" bolt depth, #5 rebar throughout, doweled and epoxied into original slab and 8" undercut under the original across the middle between the posts with same depth and prep as mentioned before. 5K psi with fiber, original slab prepped with bonding agent. Used misters on a hose time to keep it moist as it dried for 29 days. 7" Simpson wedge anchors for the 12K lift with 3/4 and 1 ton diesel trucks on it regularly and not a single stress crack 3 years later. If I'm going to climb under it, I know I can trust the work I did.
For the most part, this is an excellent retrofit, which may be considered overkill. However, there is one error in the procedure which should not be copied. Do not place sand over rock. With time, the sand will filter down, creating voids. This does take time and will be assisted by high water table. Google for more info.
the road base was called for because of the clay content of the virgin soil following compaction test. We used a 35% calcium chloride additive when compacting to ensure uniform surface with minimal porosity to prevent what you’re referring to. The. Vapor barrier of 6mil went down to prevent the sifting you’re referring to. Sand on the other hand is instantly compacted once it is wet so a layer of sand is ideal under slabs. Excellent point about sifting with sand over rock- I didn’t include this detail on my initial post as it was already long winded
At my shop the pad was only 2in instead of stated 4in. So we just dug down about 2ft and filled that with concrete. No issues after that.
That will hold it for sure.
Improper lifting and concrete prep causes the majority of issues, not concrete thickness. I've never had more than 4" of concrete. All my lifts are currently 12k 2 post, 4" concrete w/rebar. It's when people lift off center that causes a lot of stress on the anchor bolts. I've seen people lifting things that no way I'd walk under because of how lopsided the weight is. Company lift specs over the years keep increasing concrete thickness. It isn't because it can't handle it. It's issues with how it's poured, mixing, curing issues, and improper lifting that has caused manufacturers to suggest thicker concrete. If they tell you to put thicker concrete, it's to eliminate liability for them even though it's the users/installers/concrete layers fault.
Specs are changing for the idiots were are today instead of people with common sense.
I totally agree I am installing mine on my original 3.5" 50 year cured concrete.
I installed the original concrete and it was done correctly and plenty strong enough for lifts even though when I built this building it was going to be a storage building to store cars that where partially taken apart. When the lift installer drilled for anchors they probably broke out concrete at the bottom of the hole so they wanted thicker concrete for the bolts. Truth be told I bet the floor was stronger before these squares where cut out and replaced
Does anyone use a bonding agent or at least wet the old surface before pouring anymore?
I always have and always will.
I do both, pin, bondcoat, and sometimes scarify, when patching floors or foundation addition tie-ins.
Why do you need to wet the old surface??
@@nalgas5569 I’m not well versed in the scientific aspect so don’t take this as gospel-wetting it slows the chemical reaction that takes place helps create the bond between the old and new. If it’s dry the old concrete will suck the moisture out of the new concrete at the point of contact too quickly, reducing the reaction and bonding. Or,,,,,,,maybe I’m full of💩
At-least one trait of a good boss is making wise cracks . Keeps things light, and friendly.
From an engineering perspective, that could have been done by welding a larger steel plate to the base and increasing the number of bolts using the 4 inch concrete. Would have been a lot less work. Would have to know the lift capacity to know what would suffice, but doubling the base footprint would be more than enough.
Thus adding a large trip hazard. Easier isn’t always safer.
Just ask the all knowing lawyer and insurance agents. No one else knows shit
I have a question about the rebar tie in to the old concrete. You just drill a hole and stick it in? No epoxy or anything to hold it and fill up the extra space in the hole? Thanks for sharing.
Yes we stuck it in no epoxy. It definitely will not pull out. You could epoxy if you want it would not change anything.
@@bondobuilt386 Cool, thanks for the reply.
That should be a 12 inch pour for ballast stability of lift posts.
Should be 9 ft deep to get below the frost line
@@terryatpi
@@bondobuilt386 I was trying to make a funny.
Yup that is a good one. LOL @@terryatpi
Sir, please do a little PSA work. Lots of your commenters need names and addresses so the Manufacturers can learn how to properly install their products. APPARENTLY the Manufacturers are clueless! 😮 ...how do you put up with that??@bondobuilt386
This is what the manufacturer suggest ?? Doesn’t look nearly enough.
I doubt it was OEM recomendation. I suspect this install was by lift provider company practices. Y'know their motive is way different than an engineers motive working for the manufacturer. Sell lift installs, get by with minimums, go banko when sued.
What was the reason for not pre-wetting the existing concrete before pouring? Now the seams will dry out soon and be weak.
Please, for the love of god, NOBODY should be using this video as a guide of how to properly support a two post lift! They just wasted their time doing what they did in this video. It's still DANGEROUSLY inadequate! Should've cut out for one solid slab, and dug down AT LEAST 6 to 8 inches further, and dug out a little ways underneath the uncut part of the old slab to make the new pour key in underneath it as well, and use proper thick rebar throughout the entire new pour.
This is what the lift manufacturer and lift installer asked for I did not engineer this they did. 4-1/2" is all they needed but this area was only 4". My new pads are 8" thick in the middle and 5-1/2" on the edges. There not going anywhere.
Exactly. They are talking as if the vertical load is the issue. It is not. 4” concrete will hold all the load that lift can generate. The issue is the torque generated with asymmetrical loading that always occurs. With that in mind, the patchwork concrete was probably worse than the original.
The manufacturer of my lift wanted 4.5" base. If you didn't have that they said cut a 4ftx4ft square 8" deep and key it under the original slab.
@@bondobuilt386hey brother what psi u used for that 5000??
Are the lift pads supposed to be deeper than the surrounding pad? Looks like the same depth to me
The holes appear to be sloped with deeper centers.
Plus he put in a much higher psi mix concrete with epoxy or a strengthening agent
This doesn't make any sense - you never made the openings deeper, poured basically the same thickness back in, what am I missing?
He went deeper in the middle but should have left new pour go underneath existing concrete would have made it much stronger.
Just another interesting job
Thanks
That job looks sketchy as hell. I think you guys missed the point here. It’s 5” minimum on a monolithic slab. Those cut-outs and new joints now actually make it weaker than had you left it as it was 🤦🏽
We just did what the lift manufacturer asked us to do. The new pads were thicker than they even wanted. I had them over 8" in the center and about 6 around the edge.
Good thing it's a body shop. They will need one when it fails.
Just found the channel LOVE IT
Awesome hope you subscribed.
Love the smell of concrete in the morning.
Shouldn't you go deeper for the lift footings? They look just as deep as the slab itself...
I have a two post lift for personal use rated for 8700 lbs max on 5.5 inch thick rebar renenforced 5000 psi concrete on a monolithic slab. I always put Harbor Freight safety jacks on all 4 corners of the vehicle, they are supposedly rated at 4,000 lbs each, once the vehicle is in the air. They also keep the vehicle from rocking. Then again, I'm not in the business so the time spent placing the stands each time isn't important to me.
Not even going to vibrate it?
The big question is not which process to use, it's whether or not you want to accept the liability.......................
The lift company asked for it a certain way and we did it better than they asked for so we are all good.
Why wouldn,t you just use re-bar only no mesh ?
Hard work Brother, no matter what size the project is, nice job.
we did a 4x4 foot square pad when we did my buddy shop and it was 12-14 inches deep. we beat bars under the other concrete in all direction and made out little wire mess .. the guy that did the install said it was to much over kill.... i said u only live once and why did because of $50 or $100 extra concrete.. and for some of u who dont know.. ask how much is a yard of concrete... xxxxx plus delivery charge for such a small amount... or if u ordered say 3 yards then no delivery or it was cheaper.. so why not dig it deeper or bigger vs paying delivery charge and having just 5,6,7, inches of mud vs a good foot or more.. unless your wife has a great life insurance policy on you then she might only want it 2 inch thick... haha.. but its worth asking XXXX yards with no fee vs delivery fees.
It's not so much about the thickness it's about common sense.
Where is the end/ finished job?
My 3rd try to watch. The video jumps to a different one about half way. Had another one that it looked like TH-cam actually spliced with another video. When I noticed it changed I went back and found the one I was watching and fast forward to where I was and it was the other video.
Yes I had some difficulty loading this video.
👍thanks for the video
No problem.
Rebar should’ve been thicker two levels up and lower + deeper + should’ve used some commercial cement glue between old and new concrete + use a vibrator to remove air from concrete + wet the area where the concrete will be poured before using the concrete glue
If I was to go through this much work, I would make that way more than 5 inches. The addtional cost is minimal.
Take a post hole digger and dig at all four corners run rebar down the holes tie the rebar to the slab rebar this will stabilize the pad, rebar gives the concrete its strength
Your tractor ABS light will get you a violation if the D.O.T. catches up with you JS
dont look 5in deep to me, looks like same as the old slab....
Come on dude? why would we go through all that work to take out 4" and not dig it deeper. It was 8" in the middle 6" on the edges. Your comment is appreciated though because it helps the channel.
I ask because I don't know. Is that rebar adding strength to the footings? The rebar will only be anchored on one end in the new concrete. The other end will slip in tension won't it?
I think the new concrete will not be able to move. Should not be any tension on that small 4 foot square with hard stone under it.
my concrete is super sketchy so changed up from a 2 Post to a 4 Post. even if my concrete were great, the 4 Post was still likely the best choice (in my situation) given the space limitations.
That looked like max 4.5 😂 that was not 6 inches
That's what she said.
I never understood why the foot on the lift is so small .. must be so much pressure on it
yes
Way to small squares that will lift up in the future.. A 15 by 15 poured pad would have been a lot stronger.. So you just cut 6 by 6 squares and still the same thickness as the original floor. You need to go deeper at least 12 iches and pin it to the sides.Also need to wait min 30 days for concrete to cure. Bolts are another issue I would only use L type buried in the concrete
I wouldn’t suggest doweling the new to the old but sometimes it works and sometimes it doesn’t.
Made a special point of raising the rebar on the first hole - BUT DIDN'T ON ANY OF THE OTHER HOLES. - Keep this video for the Insurance claim when it fails.
Umm, I have installed lifts in the past. It seems to me that the insert pads are creating a weak spot, not making it stronger. it seems an engineer was NOT consulted. I would insist on an engineering report before allowing the first saw to touch concrete. EDIT i am saying monolithic pour, with heavier rebar for entire pad encompassing both lift upright anchor points. Also, using 3000 PSI or better concrete.
Waste of money and work. The existing concrete would have easily supported a 2 post lift
Yeah
Not my call the lift manufacturer wanted it done.
We had our floor poured deeper under the lift legs... but never bought a lift. 🤷
Someday someone will wonder why that blue tape is stuck to the floor in the barn. Oh well!
Nice maybe they will put one in.
maybe write a note down annd staple it to a post or something for a new owner 10-20-30 years later to see
Pneumatic jack hammers can make quick work of that concrete.
Many years in the construction biz- [Sorry guys the install is not good]
Concrete too shallow - Steel too thin
Instead of all that effort, You can just use a 2ft square of half inch steel plate tapered at the edges no mods required, cheaper and better and removable
Exactly what I suggested.
Is anyone else worried about the fact that they installed one post before jack-hammering the floor, shaking up the newly installed foundation?
do you use epoxy to secure the rebar you just placed?
No we did not. Not needed in this situation.
Most concrete pours are not safety critical in that they just need to support weight in compression. In this application, if there is heavy truck up, perhaps exceeding the lift rating (like the mechanics will check the GVWR), there could be torque forces on the "pier" transferred to the rebar into the other slab. How much effort and time would there be to add epoxy to the rebar just to make sure your customer doesn't have a fatal accident? To me, the difference between going the extra mile and the small details that matter. No end product shown either. More small details that don't matter here. "Not needed in this situation".
We were hired to pour the pads at 6" thick and we poured it 8" instead. We also upped the PSI of the mix and added plasticizers and accelerant to make the mix stronger and cure faster. The pads are on super compacted stone. The rebar dowels were not even required but I added them on my own. Please keep telling me I did not go the extra mile. LOL@@LisaMedeiros-tr2lz
@@bondobuilt386Rebar dowels were not required?? 🤣 Show me an engineer willing to say that.
I normally put bars all the way across 8 inches on center. The way this one is done the center is weak.
Should have used the rebar throughout and not expected the mesh to hold and added a few more inch depth to b 8" not 6"
The failure mode for these lifts is concrete breakout on the outer anchors. The center of rotation (or moment) it the inside baseplate edge. Any concrete further than about 12" from the anchors has no effect on the failure mode. When tied to the existing slab with rebar you are not going to "rotate the entire new slab out of the hole". The two keys here, assuming 3/4" anchors is that the concrete is thick enough to let the wedge anchor "set" effectively. As long as you have about 3-4" below the bottom of the drilled hole the anchor does not "see" anything deeper. There is a great piece of FREE software at the Simpson anchor site called "Simpson Strong Tie Anchor Designer" where you can enter ALL of the variables from anchor model, concrete strength and thickness, baseplate layout, Moments and forces, etc. Food for thought...
The square is just gonna break away from the old slab.
I'm confused about why the one lift post that's already anchored down is so much farther forward than where the floor was cut for the other post?
how is that not thicker than 5"?? looks plenty thick enough.
How do you price little jobs like this? Time plus materials or do you bid and if so by sqft or some other metric? Thanks
Bondo nothing like self levelling concrete!
When I built grain elevators, we poured a slump of 1 or 2, and depending on the temp outside , we used accelerate of 3% to 5%, and even hot water.
This was slipform and we average 20 to 25 feet per shift on average.
You are describing RCC concrete. It is generally compressed w/ heavy machinery. There is some usage in dam construction today but that is irrelevant. We have poured tall foundation walls for Four story commercial masonry buildings w/ a 4" slump w/ the blessing from the on site quality control lab technician & the licensed supervising civil engineer.
@@billupstateny9151 yes, on the grain silos , we vibrated the concrete in place , and if we poured a 4 slump , we have fall out because it would not be set up enough when jacking on 2 or 3, and from the top of the deck to the bottom of the form, we only had 39 inches, and we got caught many times in a thunderstorm, and the pour went on nonstop. From the moment the pour started until it ended, we poured continuously until the towers reached full height and the deck was pinned.
We has 50 ton and 20 ton jacks all around the deck, and the 50 ton jacks was near the steal steel roof beams that we transported up with us and the 20 ton jacks was in between with verticals rebar between the jacks every 12 inches.
The tanks was 40 ft Dia to 80 ft Dia and the height of the silos was 160 to 180ft a 6 pack was 40ft dia bins 160 ft tall, and if it was a drive through with a dump pit and head house, the head house was a second slip that took the tower over the head house an additional 40 ft. If concrete after the roof pour.
We poured concrete when the temp was 20 F degrees
Self leveling concrete was forbidden on these jobs, and we had an inspector on the job who took,a sample from every truck and measured the slump before it was poured, and times the truck was rejected and they would dump in the rejection pit the load of contract.
I guess when you have a million bushels of grain plus, the concrete has to be strong as possible.
The base slab was 4 ft thick and full of steel, and while the tower was going up, that base slab would sink in the ground 9 to 12 inches and when the complex was full of grain, it sink another 12 inches, and below the base slab was Man ways which had conveyors stalled for moving the grain out of the tanks and those wall was 24 inches thick.
Back when I was 19 years old in 1982 when I worked on building grain silos for government grain, it is a job one never forgets, and I look back and wonder how I ever did that type of work, being afraid of heights like I was at the time.
Someone help me out.....in 2024 what would this job cost me in the rural southeast PA?
$3000
Car lift manufacturer saying that concrete u dear post should be at least 1.5 ft deep
We have a four inch slab in our garage. Only four post lifts can go in without doing this.
Still doesn’t look deep enough
Didn't need all that rebar.🤗
How much was the job? Why not connect the two pads to be one big one? Why not have thicker rebar go all the way through?
You definitely wanna run one big pad post to post. Not two squares. I only know that because my concrete guy made me add to my materials when I installed mine. That said my buddy has his old lift in two blocks and it’s fine?
I wouldn't stand under a lift on those pads for any reason. Entire slab is supposed to be 6" reinforced, not just where the uprights go. Good grief.
do you glue the rebar into the concrete? or just push it in and that is good enough?
Did you epoxy the Rebar into the concreate? If not, why do you even tie the Rebar together? Just saying
At 2:10 the "wire mesh" looks like fence wire, doesn't look like regular wire mesh. See how easy it bends when being pulled out... Not a good original slab.
Looks great BB.
Thanks
Did you not epoxy those rebars in? What good is it going to do if it's not bound to the surrounding concrete?
Do you think they will pull out ? LOL
The forces on the rebar under a heavy load on the lifts would be bending and shear, they are not under tension, epoxy isn't going to do nothing whatsoever for that install.
How are they going to be sure they wont hit any rebar while drilling for anchors?
The concrete needs to be thicker since an anchor bolt needs at least 1" of concrete under the end of the bolt to avoid concrete blowing out. If your lifting light loads you may get away with thinner concrete but many lifts need an anchor embed of 7", plus the 1" for 8" total. Or you can design an extended baseplate that spreads the load, allows more anchors but shorter anchors. Need a engineering design for the baseplate with appropriate calculations.
Not saying this pour needs to be thicker but concrete under lifts in general, this pour of course looks great.
Looks like the cab could do with a woman’s touch ?
For sure. LOL
As an engineer, I will say I certainly would NOT rubber stamp that design! I'm wondering if this was a "dealer" that gave foundation specs. A dealer has no structural competence, and there should be something substantial from the OEM. For clarity, the "psi rating" or compressive strength of concrete is NOT the issue here! Concrete almost never fails in compression. Those tall posts become moment arms driving forces into that concrete.
( AS AN ENGINEER) How would you have done it?
@@bondobuilt386 That is an impossible answer without more details but I am not trying to throw you under a bus. You may have done as instructed, nothing more. Reality is a small pad like that will want to rotate with asymmetric loading, which will always happen with a vehicle, and that force will load only as upward sheer in those pins. My first gut reaction is more of a "pier" design to help react the loads, but again not involved. People lose their mind with depth like we are only trying to "support the load" in bearing. Not the case. When you go deeper, you are now reacting in the soil. Remember this, concrete has very high 'compression' strength, but only about 1/10th in tension so 4000psi concrete can fail at only 400lbs in tension. This is why steel is commonly used in crete as them compliment each other and steel is a tension king. It also blows people's minds to know that rebar does nothing in a thin slab until the crete breaks. Thus the massive difference in pre/post tensioning.
Nobody wants to get their hands dirty! Instead of a rake get in there by hand and make sure the concrete gets into every nook and cranny especially under the rebar then use rake for finishing especially on a weak gameplan like this one !
The lift i'm buying specifies you have 8 INCH THICK concrete
So you cut out the concrete and pour it the same depth ?Yoh make it bit deeper not half jobs
it was 8" thick in the middle 6" on the edge. We took out 4".
18 minutes? No thanks, maybe 4 tops
Wow, not nearly deep enough. That hole needs to be 3ft deep.
What size are the pads you poured here? Are they 36” x 36”x 6”? Or larger and deeper?
This is how not to setup a footing for a post lift. A moment structure should have been structured.
What kind 'on reat-ikd the vikta best
... What kind mud holds bolts best on the lift
s
Do you use epoxy to secure the rebars in the holes?
No vibration? Weak concrete
I would atleast have a foot thick for the lifts
Me too. Not much extra cost for the assurance it won't fail.
Must be the camera but it doesn’t look like 6 inch thick.
It was 8” in the middle
My ONLY concern on this would be EVs. They weigh twice what ICE cars do. The Last time I saw this done in a shop they did 5'x5' and a foot deep with rebar. This should be fun.
Saw a distributor mention parameters
It should be 4000 psi with #5 rebar at 12" oc
The cutout should be 6x6 and be no less than 8 inches deep. 6 inches is not enough like the distributor said
You need at least 6 mil vapor barrier
Should of checked how the compaction was below as well
28 days at least curing time. Not two weeks unless they pay for hot concrete with a 7 and 14 day break from a geotech to be at least 90% of required psi of 4000
Should of used slab bolsters to get the rebar off the ground and never use wire mesh.
He definitely got what they paid for. Cheap isn't quality and quality isn't cheap
Next time just use CTS Cement, Rapid Set Concrete Mix, Very Rapid Hardening Concrete, non shrinking, from 2" to 24" , 1 hr. 3,ooo PSI compression strength, 24 hrs. 4,500 PSI, 7 days 5,500 PSI and 28 days 6,000 PSI.