2 post lift and non structural concrete slab question

[roadrunner255]

Hello all,

12x40x48 post building moving along slowly.

Getting things together for a flooring quote. Slab will be non structural, and poured after the building is erected.

Plan on installing my bendpak 10k 2 post lift towards the center of the building.

Bendpak recommends a minimum thickness of 4.25 in. (108 mm) 3,000 PSI / 28 Day Aging and #6 Rebar (3/4"), and spacing of 12 in.

I was planning on using 6" of concrete, a contractor also suggested adding wire mesh as well.

Any comments?

Thanks!

 

[wssix99]

Can you share the passage you are reading in the instructions? I just read BendPak's instructions for the 10AP and they said 4.25", 3000PSI, 28 days and reinforced. (with no specifics) 6" minimum bolt spacing from cracks. (and joints in the slab)

- You need a 4" depth for the lift's anchor bolts and BendPak recommends a little more to make sure you get it. If you have less than 4", you will be in trouble. Even if you specify 4.25", best practice on this site is for YOU to watch the pour like a hawk stick a ruler in the concrete and make sure they give it to you!

- 3000PSI is a minimum, you can go with more. A higher PSI rating will have more cement in the mix and will give you a nicer finish on the floor.

- 28 days cure time is needed for crack control. No way around this minimum for any lift.

- The reinforcing BendPak recommends is insurance against cracking post-cure. It performs better than mesh. Mesh is less expensive, but you are rolling the dice a little in comparison. (#6 rebar is crazy, overkill and expensive. You should be able to reinforce a slab adequately for crack control with #4.)

 

[roadrunner255]

I opened a support case with bendpak and they referenced the 10ap for existing concrete in the following document.

BendPak lift install

Even ai is recommending #4 over #6.

Thanks

#4 or #6 rebar for non structural 6" concrete floor and a bendpak 10ap 2 post lift

Use #4 rebar (1/2" diameter) spaced at 12 inches on center in a grid pattern for a standard 6" residential or light-commercial concrete floor supporting a BendPak 10AP. [1, 2]

Why #4 Rebar is the Right Choice

• Overkill for the Application: #6 rebar (3/4" diameter) is massive, typically reserved for heavy commercial foundations, bridge structures, or massive industrial slabs. #4 rebar provides more than enough tensile strength for a 10,000-lb capacity 2-post lift like the BendPak 10AP. [1]
• Placement & Clearance: #4 rebar is much easier to handle, bend, and tie correctly. Crucially, it allows you to maintain proper concrete coverage above and below the steel (at least 2 inches of clearance) inside a 6-inch slab. Using #6 steel in a 6" slab crowds the depth and makes precise positioning difficult.

From: "Support - BendPak"
Subject: RE: Bolting lift to non structural 6" slab requirements

Hello,

If the slab is wall to wall and a new pour then 6 inches should be fine. I've also attached a link to our concrete slab requirements section of our website. This should help you answer any questions you may have. FYI use the chart on page 3 10ap, even though it says "pre-existing concrete foundation".

Car Lift Concrete Slab Requirements - BendPak

BendPak strongly recommends consulting a concrete specialist before installing a car lift. Review general slab thickness, strength and installation requirements before you begin.

www.bendpak.com

Concrete Floor Requirements - 2-Post and 4-Post Lifts - BendPak
Thank you,
T1 Parts and Technical Support Specialist

 

[firebirdparts]

Go for it. 6" is overkill, and overkill is good. I much prefer #4 rebar too, FWIW.

 

[matt_i]

They want a couple of straight parallel pieces to improve the "beam strength" between the posts (?)

There is a long history of litigation against lift manufacturers and they are squarely hoping you will issue them a get out of jail free card by diverging from requirements.

Id just do it despite the overkill. The concrete yard may be able to deliver what you need.

I'd be surprised if the cost difference between #4 and #6 is greater than $30.