Most base mix concrete is 2500psi and not 3000psi as their test.
When poured it is seldom uniform, so about the only way you can tell is to drill all the way thru and measure the bit penetration.
Ideally there should be at least some mesh reinforcement, but not always the case. In any case 4" should be enough.
For high load anchors it's always best to use epoxy. It's code required for a lot of applications. Lots of different products and instructions available. Here's an example
http://www.simpsonanchors.com/Catalo...set/index.html
I've even mixed the same epoxy I use for body repair and poured it half full into the hole.
Blow out the hole with air and flush with lacquer thinner. Has to be a clean as possible.

Any failure would not be the insert itself or the bolt, it will be the failure of the grip in the concrete.

I always drill all the way thru the concrete and then stuff with paper towel to a depth to allow for epoxy.
Always coat the inside of the anchor threads with grease first.
Another reason, is in case of failure, you can always drive the failed anchor thru the slab and install another, otherwise you're screwed and must relocate all the holes. Use the longest length anchors possible for your floor thickness.

If space allows, drilling thru the baseplate would be easiest, not just to start, but all the way thru.

Do some research and use your best judgement.

 

These are great suggestions:

So, if the depth is not known, the only true test to determine depth is to drill all the way through the concrete? I've turned a beach cottage into a two-car garage and one side "appears" to have a 5 inch depth. But than I don't know that with some test.

The epoxy suggestion I've not read about but seems as one additional insurance measure to ensure anchor bolt grip.


thanks Noonie

 

Interesting stuff. I didn't know about the group buy and ordered a Max Jax thru another outlet. :o

Couple of questions for those technically inclined:

1. During initial system bleeding I noticed a leak at one of the hose ends where the quick disconnect threads to the hose. The manual doesn't say to use teflon tape on that connection, so I didn't. Should I use teflon at those connections?

2. Regarding the epoxy recommendation for the anchors, the Wej-it anchors are supposedly removable. Does coating the threads with grease protect them from the epoxy? Curious as to how much epoxy you'd add to each hole prior to anchor insertion.

Thanks!

 

1-I would use teflon or a paste, just be sure not to get it in system.

2-The bolt is removeable, the actual wedge anchor is there for life unless you destroy the concrete removing it.
That's why I suggested to drill all the way thru, so if one screws up, then you can drive it into the base below and try with a new one or even go with a bigger size anchor if necessary.
Yes the grease is to prevent the epoxy from setting in the threads.
I would put in at least enough to fill the hole to a height above the wedge part on the anchor. A little different than the normal stud anchors.

Here's a link to some of their info
http://www.ankr-tite.com/images/prod...techmanual.pdf

and some more for their Inject-tite epoxy.
http://www.ankr-tite.com/images/prod...9_ESR-3122.pdf

In all likelyhood, with good anchors, good holes, good concrete and good assembly, the anchors alone should suffice, but for an extra 20 bucks, play it safe.

 

Picked up a tube (and accessories) yesterday from Home Depot for under $20.00!

 

I'm setting mine up for both a C3 and C5 and finding the C5 a challenge using 126 inch spacing. Because of the location of the C5 lift pads near the outer frame rail, the lift arms unextended just make it. But for the C3, must extend the lift pads to reach the frame rail lift points. See link below

MaxJax Floorplan

With this spacing for both, I have plenty of clearance to open doors and exit

 

Thanks, noonie. I appreciate all the info!

One more question though - the Power Drop anchors are designed for a mechanical or friction bond. Would the epoxy lubricate the anchor while I'm trying to set it, thus negating the mechanical attachment? If I let the epoxy dry, then I'm also unable to set the anchor since it prevents the wedge from moving and locking the anchor in place.

I'm just trying to get all my ducks in a row before I start drilling. Thanks so much!

 

Glad you asked, took a quick look at the specs and found something that may apply to some of you.

Got to hand it to the marketing types.
Nowhere in their test results did MaxJax (at least that I found) say what concrete thickness was required for installation which obviously is directly pertinent to the specs they listed for their "Anchor Bolt Stress Analysis" found here.
http://www.maxjaxusa.com/specifications.html
Most others offer that info in advance.

From their FAQ page
Well here are the specs for the anchors they say they supply
http://www.drillspot.com/products/43...Drop-IN_Anchor

So they are really 7/8 dia and 3-13/16" long, but the clincher is that it also says a 5-1/2" MIN hole depth is required.
Now that is with a 1/2" reveal to the concrete surface.
I don't know if the 3-13/16" is the collapsed length after install or not.

The problem is that a lot of of garage floors end up being 3-5/8" thick (2x4 size) but called 4".
If you find your floor to be min thickness, then you could probably eliminate the 1/2" reveal and hopefully with some good epoxy, the wedge will catch enough, but it will be very close.

Of course the ideal way to do this would be to use an anchor like this,
B3Z Column Anchors here,
http://www.williamsform.com/Concrete...n_anchors.html

but cutting and cement would be necessary. Not that big a deal really. Much better for load too.
When you place your column and drill your first hole, you'll know.
You'll also be able to see what the installed length of the anchor will be.

Of course, I'm sure MaxJax will address those little issues with the installation instructions delivered with the lift.

If you run into problems, let me know.

 

The offer for help is much appreciated! I forgot to mention that I have a post-tension foundation, so my install is complicated slightly by the tension cables. I bought a good metal sensor for concrete and it seems to work quite well. I recently had a new driveway poured, so after the demo' I was able to locate the garage floor anchors for the cables running in that direction. I marked the garage floor with a little X and tested my sensor. It seems very accurate.

Anyway, once I drill I'll see how thick the concrete is and base the epoxy decision on that criteria along with how well I'm able to create a suitable hole for each anchor. The house is 30 years old, but the concrete floor is in very good shape with very few cracks.

Thanks again for the ideas, links and info!

 

I'm finding the install guide marginal at best, especially with the floor plan which is critical before one starts drilling holes.

 

Noonie

Well, it looks like you've described my situation. It's a 55 year-old concrete floor so well cured and I would hate to cut it up. I drilled two holes, the "A" for each column to test depth. I used a weatherstripe tool, (curved tip) to determine at what point it begins to curl under the base concrete and feels about 3 3/4.

If I cut out the reveal and use epoxy, will this work?

The MaxJax is tested for 6,000 lb but the heaviest Corvette, my C3, is 3,500. Is it safe to assume that if I avoid lifting trucks, I'm not putting the full load on the system?

I've updated my floor plan. I'll install a second set of anchors for the C5, using the rear anchors for the C3 column location for the C5. That gives me 130 spacing for C5 and 124.5 for the C3.

MaxJax Floorplan

 

Hunt, thanks for posting the floor layout. This really helps since I'm getting ready to drill today for my C5. Your diagram shows where you're measuring from, which syncs with what I figured. Some of the measurements posted by others were confusing since they must've been measuring from somewhere other than the outside of the base plates. Good luck with your install!

 

Thanks DV

Having a tech writing background helps to convey this type information in sufficient detail that others can pick it up and adapt or use. I found the MaxJax install manual "limited" and know if contracted, how I would rewrite the sucker. There could be a well developed section on the just the floor plan to assist the DIYers like us.

 

If you can post a pic of the anchors supplied with a rule and/or draw up a diagram with measurements that would help a lot.

 

Pic is a bit fuzzy but anchor length comes in at 3.75. I think camera digital couldn't decide to focus on those little black lines are the anchor in the foreground.

Wejit

 

Pic was good, but I'm interested in the other end. A pic of the whole anchor with the tape would be best.

Question
Is there a void where the dirt has settled under the concrete or is the dirt still up to the bottom of the concrete? You can check with either a flashlite or by brobing lightly with a dowel, drill bit pencil etc and measuring.

 

Here is what is supplied by Danmar. http://www.alliedbolt.com/images/PowerDropAnchor.jpg

 

Ok, a few different shots of the wejit. I include a shot of the end because the camera distorts the location of the anchor on the tape measure.

wejit2

wejit3

wejit4

One side measures 4.5 in and after I punch around the rod goes into sand and substrate. I can see bits of concrete debris. The other side barely measures 3.5, closer to 3 7/16 in. At first the substrate seemed firm until I stir around, than I was eventually able to punch thru.

 

Great pics

As I suspected the nominal length advertised for the anchor is misleading.
The actual working wedge in the anchor is “2-3/4” plus the reveal of 1/2” that they recommend gives 3-1/4” length. Your drilled round part of the hole must be 3-1/4” deep minimum for the wedge to grip, so you should be fine. If some holes are less, there is a fix.
So be aware that the tensile load on the concrete will be from about 3” to the surface maximum. In other words, using these anchors, it basically doesn’t help if your slab was 10” thick. If the slab was indeed thicker, I would set the anchor deeper and use longer bolts.
You should use the 1/2” reveal since you have the depth, because tightening these wedge type anchors, they have a tendancy to raise a bit until the wedge secures itself, so your final reveal may be a little less.
Not to scare you, but you can possibly experience 3 failure modes.
1st – conical upward fracture failure of the concrete
2nd – anchor grip in the concrete
3rd – anchor failure itself (bolt threads, fracture etc)
The good news is that the concrete being that age, is about as strong as possible. Any remote possibility of failure would probably be a loosening of the anchors first, so don't sweat it.

Try not to drill into the dirt below and use the epoxy you bought.
Tighten about 90% (you will be guessing) and then try and tighten a little more after the epoxy has set (next day).

Enjoy your new lift.

 

Thanks noonie for the analysis!

Sounds like if it comes in about 1/4...I'm good to go with this configuration.

Sounds like anyone could experience one of these 3 failures?

Tell us about aged concrete versus new. What properties "mature" with aged concrete that help anchor in this type installation.