fork lift load on 3" elevated slab
fork lift load on 3" elevated slab
(OP)
I have a 9"x20"+3" concrete joists. They are going to install a 2400 lbs generator that requires the use of a fork lift. The fork lift will drive through this 3" slab loaded with the generator weight. Can someone point me to the right direction on the analysis on the slab? Ive analyzed the beam and I am comfortable it will support the load but I am worried about the front wheel load resting on the 3" slab. I havent done any AASHTO design so I am not sure what I need to do with this kind of load. Do I need to magnify it since it is a moving load? HOw about the area in contact to concrete? Anyway, any tips would be appreciated.
Never, but never question engineer's judgement






RE: fork lift load on 3" elevated slab
With a cart, all 4 wheels might have about the same load 2400# / 4 but a fork truck would be carrying the total load on only the front wheels plus the weight of the truck. Check to make sure the wheels do not punch thru the slab.
RE: fork lift load on 3" elevated slab
RE: fork lift load on 3" elevated slab
RE: fork lift load on 3" elevated slab
Never, but never question engineer's judgement
RE: fork lift load on 3" elevated slab
That said, coming up with an adequate dunnage system will likely be easier.
A crane mat is typically a series of heavy timber boards, often oak, sometimes pine, secured together such that the "mat" can be placed on the path a crane or other heavy equipment must travel and not overload the soil. Its application here would assume that the wood members have sufficient capacity to carry the load in place of the slab and are sufficently stiff to prevent the members from simply transferring the applied load in bearing. However, with a thick enough mat and your tightly spaced joists, all loads might be sufficent to assume bearing to the support anyway.
Are there limitations of the height in this area? Would building up a mat of wood or steel members be feasible?
To get aroud the members bearing on the slab you are trying to protect, I have used wood blocking aligned with beam members such that the dunnage members, which have the strength but lack the stiffness to load prior applying load on the slab, will span over the blocking and have a space to deflect.
Do you have a spec sheet for the exact fork lift to be used? This is not the first time this scenario has occurred and the contractor and forktruck manufacturer can provide a substantial amount of data about the lift.
Good luck and post back.
Daniel Toon
RE: fork lift load on 3" elevated slab
Never, but never question engineer's judgement
RE: fork lift load on 3" elevated slab
No matter what solution is chosen, work will need to be done and money spent. Is a system of dunnage so stiff that the slab will not be engaged cheaper than the hours needed to locate and properly layout the joist pattern at the top of slab? Probably not.
Have you been involved with the contractor or personnel responsible for performing the work? Do they have any ideas?
Seeing as my specialty is shoring, I'd be inclined to support the slab at a tight spacing and use plywood or sheet steel to locally protect the slab. But without knowing the particulars of the equipment and building, it is impossible to determine the best solution.
Communication between yourself and those implementing the solution will be key to the success of your efforts.
Best of luck!
Daniel
RE: fork lift load on 3" elevated slab
Never, but never question engineer's judgement
RE: fork lift load on 3" elevated slab
RE: fork lift load on 3" elevated slab
Never, but never question engineer's judgement
RE: fork lift load on 3" elevated slab
RE: fork lift load on 3" elevated slab
A two ton forktruck has a loaded front axle load in excess of 10,000 pounds (5000# per wheel).
RE: fork lift load on 3" elevated slab