Jib crane base mount
Jib crane base mount
(OP)
Hi everyone,
I need to mount a jib crane on a concrete floor. I have a base plate of 24"x24"x1". The concrete slab is 12" thick and it is armed with steel rods. The torque improve by the jib crane is 160 000 lbf*po. My question is : How can I know if the concrete will withstand the stress?
thank you!
I need to mount a jib crane on a concrete floor. I have a base plate of 24"x24"x1". The concrete slab is 12" thick and it is armed with steel rods. The torque improve by the jib crane is 160 000 lbf*po. My question is : How can I know if the concrete will withstand the stress?
thank you!






RE: Jib crane base mount
What size and spacing of reinforcing in slab?
Where is the reinforcing located (top, middle, bottom) in your slab?
Will you be embedding the bolts or will they be post installed anchor of some sort?
RE: Jib crane base mount
1. Axial load (vertical shear on foundation)
2. Bending moment that will vary due to the amount of horizontal rotation that the job will do.
3. Torsional load depending on the horizontal rotation of the jib and the angle of the wire rope with the vertical.
4. You may even have lateral shears at the column base.
I do not recommend placing the jib on a slab that has the following unknown (at least you did not indicate them):
1. Slab thickness
2. Compressive strength
3. The area of reinforcing steel in the slab
4. The location of the steel within the slab
5. The allowable soil bearing pressure
6. Is the jib going to be fixed at the base or pinned and it the top of the jib column going to be restrained/pinned?
As you see, you may need to do more investigation and have a qualified engineer make the design and recommendations for you. Giving us the bending moment of 160 Kip-Foot is not enough.
Regards,
Lutfi
www.cdeco.com
RE: Jib crane base mount
For a two way slab, the problem becomes much more complicated and will require a much more sophisticated analysis.
I assume that this is a structural slab and not a slab on grade.
If you do not feel confident in analyzing this by yourself, then I recommend hiring a licensed structural engineer.
I hope this quick outline has helped. Best of luck!
RE: Jib crane base mount
o | 3" between the end and the bolt
|
| 9" between the two bolts
o |
|
|
_o_|
For a total 24"x24" by 1" thick
I use Hilti HVA chemical anchor of 3/4" by 6 5/8" long (post installed)
The slab is reinforced by rod #6 spaced bye 12" at the top and the bottom of the slab.
The vertical load is 555lbs and the moment 160 100 lbs*po.
The concrete used is 3000psi.
With this, I'm searching for a simple and general method to calculate how much torsion a concrete slab can hold. I don't need something too accurate, I just looking for an approximative value.
Thank you for your help
RE: Jib crane base mount
RE: Jib crane base mount
Be careful here, if you aren't sure what you are doing - get some help.
RE: Jib crane base mount
What is the "po" in lbs*po?
RE: Jib crane base mount
Your help is really appreciated. I think I will give my problem to a structural enginneer to be sure of what it is done.
thank you all