LocostUSA.com

Learning how to build Lotus Seven replicas...together!
It is currently March 28, 2024, 5:08 am

All times are UTC - 5 hours [ DST ]




Post new topic Reply to topic  [ 25 posts ]  Go to page 1, 2  Next
Author Message
 Post subject: Car lift install
PostPosted: December 2, 2019, 11:21 pm 
Offline
User avatar

Joined: October 13, 2011, 9:19 am
Posts: 1343
Location: Denver Co
So I am getting around to installing my C-7000 car lift and found out that my floor is only 3.5" (actually less that that) where the lift will go which isn't thick enough. So I decided it would be best to pour a new pad. I figured a 5000psi 28" x 28" x 12" deep with a 6" under cut (to tie it back to the existing slab somewhat) would be best. But is it? After looking around online I am seeing everything from 2ft x 2ft to 4ft x 11.5ft requirements will all sorts of thicknesses. Any one have any real thoughts?? I'm not even sure how to calculate the required overturn moments so they I can figure out how much the concrete needs to weigh... I'm not a civil or structural guy. I feel like my size will not be a problem for the race car but at some point I know I'm going to put my Explorer on it and be worried.

Here is the hole :D
Attachment:
20191129_133111-1612x1209.jpg


You do not have the required permissions to view the files attached to this post.

_________________
My build: http://www.locostusa.com/forums/viewtop ... 18&t=13096


You can build the most awesome thing in the world but at some point, an 80yr old man in a crx is probably going kick your butt on the track... don't ask me how I know.


Top
 Profile  
Reply with quote  
 Post subject: Re: Car lift install
PostPosted: December 3, 2019, 2:21 pm 
Offline

Joined: November 13, 2009, 9:31 pm
Posts: 138
Location: Connecticut
Not a licensed PE, so take this with a grain of salt...

I would make a continuous pad between the two posts, this would take care of the lateral tipping concern, and then make it long enough to go past the center of gravity of anything you would lift to eliminate that concern. I would pour it at least 6" thick with rebar ~2" up from the bottom.

This goes along with what I found online:
Q: How large "stand alone" concrete pad is needed for an
outdoor lift?

A: 2-post lift:
The concrete should be twice the required thickness of a "normal" concrete
floor for the lift's weight capacity. The "slab" should extend at least 24
inches past the outside of each column (side to side) and one foot (front
to back) longer than the end of the extended lift arms when moved to their
"fully extended" position.

_________________
Planning a Duratec powered, Miata suspended 442


Top
 Profile  
Reply with quote  
 Post subject: Re: Car lift install
PostPosted: December 3, 2019, 7:33 pm 
Offline
User avatar

Joined: March 19, 2011, 10:22 am
Posts: 2386
Location: Holden, Alberta, Canada
duratec7 wrote:
Not a licensed PE, so take this with a grain of salt...

Same here

If I were doing this I would sink a 12"-14"diameter x 6'-8' deep concrete piling (using piling tubes) with rebar and hoist tie bolts for each pillar, kinda like what they do for large street lamp posts.

_________________
Perry

'If man built it, man can fix it'
"No one ever told me I couldn't do it."
"If you can't build it safe, don't build it."

Perry's Locost Super Che7enette Build
Perry's TBird Based 5.0L Super 7 L.S.O
Perry's S10 Super 7 The 3rd
Perry's 4th Build The Topolino 500 (Little Mouse) Altered
Perry's 5th Build the Super Slant 6 Super 7
Perry's Final Build the 1929 Mercedes Gazelle


Top
 Profile  
Reply with quote  
 Post subject: Re: Car lift install
PostPosted: December 3, 2019, 8:21 pm 
Offline
User avatar

Joined: July 17, 2008, 9:11 am
Posts: 6414
Location: West Chicago,IL
Geeze Perry, that seams like a much over built design in my un-Licensed PE opinion. It is ~700# to 1350# of concrete per slab/piling. I was thinking of just driving a few steel rods down a few feet before pouring the concrete. I think 8"-9" dia x 42 inches deep pilings are common for deck supports around here. The depth varies depending on the depth of the frost line. I don't pretend to know myself. Mjalaly, what do the instructions of your lift say is needed? Certainly it is specified somewhere in the installation instructions.

_________________
Chuck.

“Any suspension will work if you don’t let it.” - Colin Chapman

Visit my ongoing MGB Rustoration log: over HERE

Or my Wankel powered Locost log : over HERE

And don't forget my Cushman Truckster resto Locostusa.com/forums/viewtopic.php?f=36&t=17766


Top
 Profile  
Reply with quote  
 Post subject: Re: Car lift install
PostPosted: December 3, 2019, 9:32 pm 
Offline
User avatar

Joined: October 13, 2011, 9:19 am
Posts: 1343
Location: Denver Co
rx7locost wrote:
Mjalaly, what do the instructions of your lift say is needed? Certainly it is specified somewhere in the installation instructions.


The instructions are garbage. Even the vendor was no help. They just told me the manual says 4" thickness but that's the thickness requirement for an existing floor... mine isn't 4". I have been reading more on the web and it looks like quite a few people reccomend a 4ft x 4ft pad 12" deep.

_________________
My build: http://www.locostusa.com/forums/viewtop ... 18&t=13096


You can build the most awesome thing in the world but at some point, an 80yr old man in a crx is probably going kick your butt on the track... don't ask me how I know.


Top
 Profile  
Reply with quote  
 Post subject: Re: Car lift install
PostPosted: December 3, 2019, 10:29 pm 
Offline
User avatar

Joined: July 17, 2008, 9:11 am
Posts: 6414
Location: West Chicago,IL
The requirement for Bendpak 10,000 lift is:
Quote:
https://www.bendpak.com/XPR-10-Series-T ... endPak.pdf

• Concrete specifications. Make sure the concrete is at least 4.25 inches thick, 3,000 PSI, and cured for a minimum of 28 days. Do not install the Lift on cracked or defective concrete. Anchor Bolts must be more than 6 inches from cracks in the concrete or from a wall.


I would trust Bendpak's requirements. They are well respected. Interpreting your situation based on the Bendpak instructions, a min of 6" beyond the bolt pattern of the lift would be appropriate for the cut. 6 inches beyond the base outline would be better with some margin for error. Dig out 4-1/4 inches below the bottom of the existing concrete. Extend the hole under the existing concrete the same 4-1/4 inches on all 4 sides. That would give you the min thickness for the new concrete under the old with a 45 degree angle of "locking" under the old. I would also wash the underside of the old concrete and spray with concrete bonding adhesive to enhance adhesion. not to mention the previously mentioned reinforcement steel. I would check that the crushed stone base under the concrete is still enough since you are digging out deeper than the original excavation and possibly the underfill.

And wait 28 days for the concrete to cure before drilling and installing the anchor bolts.

So the safety factors are:
1) Sackrete and Quikrete found at the home stores are typically 4000 PSI, Higher PSI can be found.
2) You are using a 7000# lift. The above instructions are for a 10,000# lift
3) Cut 6" beyond the base vs 6" from the anchor bolts
4) The Bendpak lifts are ALI certified. I assume that includes the min installation requirements.

YMMV of course and I have no expertise in these matters. But I would not be concerned if I were installing a 7,000# lift using the above guidelines.

Don't come after me if things don't work out for you using these guidelines. :mrgreen:

_________________
Chuck.

“Any suspension will work if you don’t let it.” - Colin Chapman

Visit my ongoing MGB Rustoration log: over HERE

Or my Wankel powered Locost log : over HERE

And don't forget my Cushman Truckster resto Locostusa.com/forums/viewtopic.php?f=36&t=17766


Top
 Profile  
Reply with quote  
 Post subject: Re: Car lift install
PostPosted: December 3, 2019, 10:41 pm 
Offline
User avatar

Joined: October 13, 2011, 9:19 am
Posts: 1343
Location: Denver Co
Bendpak actually specs out something extreme. Pretty much a gigantic pad with a 6in undercut 12" deep

https://www.bendpak.com/car-lifts/concr ... uirements/

_________________
My build: http://www.locostusa.com/forums/viewtop ... 18&t=13096


You can build the most awesome thing in the world but at some point, an 80yr old man in a crx is probably going kick your butt on the track... don't ask me how I know.


Top
 Profile  
Reply with quote  
 Post subject: Re: Car lift install
PostPosted: December 4, 2019, 12:59 pm 
Offline
User avatar

Joined: July 17, 2008, 9:11 am
Posts: 6414
Location: West Chicago,IL
My Bad! Ignore my earlier posts. :cheers:

It makes sense to me now why Bendpak wants a continuous pour from one post to the other. 2-post lifts do not take a pure vertical load like a 4-post lift does.

_________________
Chuck.

“Any suspension will work if you don’t let it.” - Colin Chapman

Visit my ongoing MGB Rustoration log: over HERE

Or my Wankel powered Locost log : over HERE

And don't forget my Cushman Truckster resto Locostusa.com/forums/viewtopic.php?f=36&t=17766


Top
 Profile  
Reply with quote  
 Post subject: Re: Car lift install
PostPosted: December 7, 2019, 7:03 am 
Offline
Automotive Encyclopedia
User avatar

Joined: December 22, 2006, 2:05 pm
Posts: 8037
IMH and amateur O, for balancing 10,000 lbs on two six foot pillars with a sqft base, I would augment the loading pads with four 1/4x5x5 base plates, ten feet from the upright, bolted to studs epoxied into the floor, then fit threaded rod with a turnbuckle adjustment for tension loads to keep the pillar vertical and help prevent concrete cracking that would require a repour.

Think about an inverted truss (warren,pratt, etc). With trusses, there would be no need for extra thick concrete since the load would be spread over a much larger area. With a long enough truss there would be no need to bolt it down.

Consider what the dynamic load would be if one of the outriggers was not placed properly under a frame rail and a vehicle like a truck with bad weight distribution slipped. Take a look at youtube vids of vehicles falling off lifts.

_________________
Miata UBJ: ES-2074R('70s maz pickup)
Ford IFS viewtopic.php?f=5&t=13225&p=134742
Simple Spring select viewtopic.php?f=5&t=11815
LxWxHt
360LA 442E: 134.5x46x15
Lotus7:115x39x7.25
Tiger Avon:114x40x13.3-12.6
Champion/Book:114x42x11
Gibbs/Haynes:122x42x14
VoDou:113x44x14
McSorley 442:122x46x14
Collins 241:127x46x12


Top
 Profile  
Reply with quote  
 Post subject: Re: Car lift install
PostPosted: December 8, 2019, 3:12 pm 
Offline
User avatar

Joined: October 13, 2011, 9:19 am
Posts: 1343
Location: Denver Co
So dug some more and now the one side is 28 x 4ft. Just that extra 20in was a lot of work since I don't have a jack hammer. That seam down the center is actually the center of the garage so now I am thinking I should go the whole way and connect the two sides but again that is a ton of work. I probably don't need a 12" depth the whole way maybe just 6 in deep in the center and 12" deep under the pad as shown. I'm also not sure if I really need it to be 4ft wide the whole way. I think 3ft around the lift post is fine. This might work the way it is too since the soil is so damn hard and I would probably pull the anchors out first.


You do not have the required permissions to view the files attached to this post.

_________________
My build: http://www.locostusa.com/forums/viewtop ... 18&t=13096


You can build the most awesome thing in the world but at some point, an 80yr old man in a crx is probably going kick your butt on the track... don't ask me how I know.


Top
 Profile  
Reply with quote  
 Post subject: Re: Car lift install
PostPosted: December 10, 2019, 12:58 pm 
Offline
User avatar

Joined: October 24, 2008, 2:13 pm
Posts: 5326
Location: Carlsbad, California, USA
I think Home Depot rents electric jack hammers. That might help you a lot.

Cheers,

_________________
Damn! That front slip angle is way too large and the Ackerman is just a muddle.

Build Log: viewtopic.php?f=35&t=5886


Top
 Profile  
Reply with quote  
 Post subject: Re: Car lift install
PostPosted: December 14, 2019, 11:45 am 
Offline
User avatar

Joined: April 15, 2011, 10:39 pm
Posts: 222
Location: Dallas, PA
Maybe dig down and add a sonotube.


You do not have the required permissions to view the files attached to this post.

_________________
Dan Lipperini Jr
www.RaceLabz.com


Top
 Profile  
Reply with quote  
 Post subject: Re: Car lift install
PostPosted: December 15, 2019, 7:54 pm 
Offline
User avatar

Joined: October 13, 2011, 9:19 am
Posts: 1343
Location: Denver Co
Closer. I just need to dig some dirt and then have someone cement dirt in.

Do I need gravel at the bottom or just mesh?


You do not have the required permissions to view the files attached to this post.

_________________
My build: http://www.locostusa.com/forums/viewtop ... 18&t=13096


You can build the most awesome thing in the world but at some point, an 80yr old man in a crx is probably going kick your butt on the track... don't ask me how I know.


Top
 Profile  
Reply with quote  
 Post subject: Re: Car lift install
PostPosted: December 15, 2019, 9:32 pm 
Offline
User avatar

Joined: December 4, 2011, 6:19 pm
Posts: 829
You need;
- a well compacted base...don't skimp on compacting the base (!!!), and
- mesh or other reinforcing steel set up on chairs so that it will remain in the center of the new pour plus you'll need to vibrate the pour to eliminate voids under the steel, and
- reinforcing steel bars that are epoxied into holes drilled in the side of the old slab all around the perimeter of the hole to tie the old slab and the new slab together.

Check your local building code for specs on the steel size required, the spacing of the tie bars and the spec of the epoxy.

Have fun! (I'm not a fan of concrete work)

_________________
Bill H
Winnipeg, MB, Canada


Top
 Profile  
Reply with quote  
 Post subject: Re: Car lift install
PostPosted: December 16, 2019, 9:19 am 
Offline
User avatar

Joined: June 20, 2019, 12:34 pm
Posts: 585
Typically, the stronger reinforcement comes from rebar tied together and embedded about halfway down into the concrete. If you Google "rebar", you will see samples showing sizes and ways to tie it together. Typically, you just need to runs some lengths across the long ways of the opening and a few across the lengthwise lengths. You can tie them together with some steel wire twisted around each crossing of the rebar.
Attachment:
Rebar.jpg


The other choice (also a little bit easier) but not quite as strong, is use wire mesh.
Attachment:
Wire mesh renforcement.jpg



Make sure you use something to support the mesh or rebar off of the ground to allow the steel to embed into the middle of the concrete pad. And do add gravel at the bottom of the new opening, this allows you to be on a solid bed. This gives resistance against "bending" and transfers the pressure to the entire slab.

Thom


You do not have the required permissions to view the files attached to this post.

_________________
Thom


Top
 Profile  
Reply with quote  
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 25 posts ]  Go to page 1, 2  Next

All times are UTC - 5 hours [ DST ]


Who is online

Users browsing this forum: No registered users and 2 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Jump to:  
POWERED_BY