Anchor depth

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Ok guys. I got some pics. Here you’ll see the original outline of the 3x3 squares I had poured. You’ll also see the final positions where the lift columns will need to go. They will be 6 inches from the nearest control joint as they cannot he mounted any closer. The lift column will need to be anchored in those positions as this will give me the most amount of workable area possible. The anchors provided measure 5.5inches in length with a diameter of 3/4inches. I’m not sure how I feel about this since the holes in the base of each column measure closer to 1in. The lift is an overhead design as well.

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The base of my slab is gravel, then a vapor barrier and then concrete. When I cut the new squares. I’ll add gravel to give me the desired depth of 12in. Then vapor barrier then concrete correct? Pic of slab when first finished

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RustyRatRod said:
It's a very simple procedure to bust up the concrete, dig deeper and pour new. Nothing to it. If you fail to do this, you have no one to blame but yourself when you get killed. Or a loved one. Your wife......your child, friend, dog......whatever.
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When I cut the new holes. Do I put anything in them as far as rebar, wire, fiber mesh? Do I need to tie these holes into the surrounding concrete?
 
Evan Dutch said:
Do I need to tie these holes into the surrounding concrete?
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If I was doing what you are planning to do, I would tie it in, yes. I would accomplish this by taking a concrete bit and drill into the existing concrete and cut down some rebar to have 'fingers" pointing out into your fresh pour....
 
Evan Dutch said:
When I cut the new holes. Do I put anything in them as far as rebar, wire, fiber mesh? Do I need to tie these holes into the surrounding concrete?
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Yes, you need to tie the new concrete into the old with pins. Drill holes into the sides of the new pits and insert either cut rebar or bolts (3/8 inches or more in diameter) into them, so they are embedded into the old concrete and the new concrete at least 3 inches in each. Use at least two on each side. Keep the pins 4 or more inches from the corners and away from where your anchors will be. Consider using L threaded anchor bolts instead of the wedge anchors. Make a template to hold them In place while You pour the new concrete.

no, you don’t need to add rebar or welded wire mesh in the new pours.
 
Dicer said:
If I was doing what you are planning to do, I would tie it in, yes. I would accomplish this by taking a concrete bit and drill into the existing concrete and cut down some rebar to have 'fingers" pointing out into your fresh pour....
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Yup, this^^^^^^
 
68gtxman said:
If I was going to break out and repour a section of the concrete floor to make it thicker, I would also make a template to match the anchor bolts and cast in L anchor bolts. I’d also side drill into the sides of the new hole and place pins into them before pouring, to tie the new concrete into the existing.
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This right here. Thats the best above all!
 
68gtxman said:
Yes, you need to tie the new concrete into the old with pins. Drill holes into the sides of the new pits and insert either cut rebar or bolts (3/8 inches or more in diameter) into them, so they are embedded into the old concrete and the new concrete at least 3 inches in each. Use at least two on each side. Keep the pins 4 or more inches from the corners and away from where your anchors will be. Consider using L threaded anchor bolts instead of the wedge anchors. Make a template to hold them In place while You pour the new concrete.

no, you don’t need to add rebar or welded wire mesh in the new pours.
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should the new pits be the exact size of the lift columns or larger? Say, 3x3?
 
Evan Dutch said:
should the new pits be the exact size of the lift columns or larger? Say, 3x3?
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They should be large enough so that the nearest an anchor bolt will be to a new edge is at least 4 inches. So you can make it 8 inches wider and longer than the baseplate. I myself like to oversize things, so 4 inches to edge is a minimum. 6 inches would be better. If you go that route, make it 12 inches wider and longer than the baseplate.
 
68gtxman said:
They should be large enough so that the nearest an anchor bolt will be to a new edge is at least 4 inches. So you can make it 8 inches wider and longer than the baseplate. I myself like to oversize things, so 4 inches to edge is a minimum. 6 inches would be better. If you go that route, make it 12 inches wider and longer than the baseplate.
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let me see if I’m understanding this correctly. I’ve attached some pictures of what I believe would be correct in the way I’m to go about this. How close should these new cuts be to the control joint? Since my lift will have to be placed exactly 6inches from the control joint and I need to have at least a few inches from the edge of the new hole. Wouldn’t I have to cut the squares relatively close to the control joint? Like maybe 2 inches? First pic: top view, second pic: side view, third pic: overall top view layout

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Pulled from the Gregsmithequipment website (where I got the lift from). I know it says 10inches but if I’m already busting up the concrete I’ll make it 12inches deep

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68gtxman said:
Yes, you need to tie the new concrete into the old with pins. Drill holes into the sides of the new pits and insert either cut rebar or bolts (3/8 inches or more in diameter) into them, so they are embedded into the old concrete and the new concrete at least 3 inches in each. Use at least two on each side. Keep the pins 4 or more inches from the corners and away from where your anchors will be. Consider using L threaded anchor bolts instead of the wedge anchors. Make a template to hold them In place while You pour the new concrete.

no, you don’t need to add rebar or welded wire mesh in the new pours.
Click to expand...

rebar should only be inserted into the sides of the existing concrete, NOT vertically into the new holes?
 
Evan Dutch said:
let me see if I’m understanding this correctly. I’ve attached some pictures of what I believe would be correct in the way I’m to go about this. How close should these new cuts be to the control joint? Since my lift will have to be placed exactly 6inches from the control joint and I need to have at least a few inches from the edge of the new hole. Wouldn’t I have to cut the squares relatively close to the control joint? Like maybe 2 inches? First pic: top view, second pic: side view, third pic: overall top view layout

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I would extend the size to meet the control joint because leaving a 2 inch wide strip between your new concrete and the joint will make it crack at the corners. So make your cutout 36” x 38”. A 4’x4’ box is way overkill. They recommend rebar in the new concrete. It wouldn’t hurt and then you won’t be worried about it if you add it. Use 2 bars each way. You can even tie them into your new pins to keep them evenly spaced. Your drawings look good with the one mod to extend to the control joint. You don’t need vertical rebars.

Also, use the highest strength concrete you can buy (close to 5,000 psi?). Mix it using the least amount of water possible, because mixing it with more water makes it weaker than the mix design strength. Vibrate it if you can while placing it, but if you don’t have access to a vibrator, you can tamp it down to ensure it fills all voids.
 
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68gtxman said:
I would extend the size to meet the control joint because leaving a 2 inch wide strip between your new concrete and the joint will make it crack at the corners. So make your cutout 36” x 38”. A 4’x4’ box is way overkill. They recommend rebar in the new concrete. It wouldn’t hurt and then you won’t be worried about it if you add it. Use 2 bars each way. You can even tie them into your new pins to keep them evenly spaced. Your drawings look good with the one mod to extend to the control joint. You don’t need vertical rebars.

Also, use the highest strength concrete you can buy (close to 5,000 psi?). Mix it using the least amount of water possible, because mixing it with more water makes it weaker than the mix design strength. Vibrate it if you can while placing it, but if you don’t have access to a vibrator, you can tamp it down to ensure it fills all voids.
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Should i bring the new holes to where they are even with the control joint or to where they overlap, thus eliminating that part of the control joint?

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68gtxman said:
I would extend the size to meet the control joint because leaving a 2 inch wide strip between your new concrete and the joint will make it crack at the corners. So make your cutout 36” x 38”. A 4’x4’ box is way overkill. They recommend rebar in the new concrete. It wouldn’t hurt and then you won’t be worried about it if you add it. Use 2 bars each way. You can even tie them into your new pins to keep them evenly spaced. Your drawings look good with the one mod to extend to the control joint. You don’t need vertical rebars.

Also, use the highest strength concrete you can buy (close to 5,000 psi?). Mix it using the least amount of water possible, because mixing it with more water makes it weaker than the mix design strength. Vibrate it if you can while placing it, but if you don’t have access to a vibrator, you can tamp it down to ensure it fills all voids.
Click to expand...

when I drill into the side of the existing slab to install rebar, will that compromise the current slab since it’s only 4in thick? Does the rebar need to be fastened in place? I’ve heard of people using epoxy, axle grease, or just inserting them into the holes. Would it be a good idea to dig out beneath the slab and then pour? I think this is known as underpinning. Would it be a bad idea to have these new pads be fibermeshed reinforced?
 
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famous bob said:
Like I said before , I`d anchor the top to the ceiling both ways , forward and backward . You cant afford an accident !!
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It’s a prefab steel building. The building company says not to use the structure of the building to brace anything other than the building itself
 
Evan Dutch said:
It’s a prefab steel building. The building company says not to use the structure of the building to brace anything other than the building itself
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I know a professional mech , that has 3 done that way , no problems , but he doesn`t have them anchored by a joint either . He installed two of them himself, a friend and a forklift----------
 
famous bob said:
I know a professional mech , that has 3 done that way , no problems , but he doesn`t have them anchored by a joint either . He installed two of them himself, a friend and a forklift----------
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If I place the lift within the new 4ftx4ft square centered. It will have 15in between either side of the lift column and the edge of the 4ftx4ft square. So it would be no closer than 15in to a separation joint. Will this be far enough?
 
Evan Dutch said:
If I place the lift within the new 4ftx4ft square centered. It will have 15in between either side of the lift column and the edge of the 4ftx4ft square. So it would be no closer than 15in to a separation joint. Will this be far enough?
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I wouldn`t say , but I`d sure make it thick , strong concrete --------------- professionally mixed too.
 
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