Heavy forklift\load on saturated gravel

Well, hopefully the experienced rigger\engineering types can help me out here.

Im moving a 10000lb machine in this weekend using a 15000lb forklift (25000lb actual weight'ish).
I've done this 4 times now, and under normal circumstance, its a no brainer for me.

The variable this time is that weve had non stop rain for a week, and my 24" of "A" gravel is completely saturated.
What i normally do, even with dry gravel is lay down sheets of 3/4" fir plywood for the fokrlift to drive on.
I always get an indoor tire machine, so the plywood is to be nice to the tires, and man.... get one of those pigs stuck once.... trust me...

My concern this time around, is with the saturated base, will that 3/4 plywood stand up? Or is it going to flake out on me, leaving me with a bastard of a situation?
I wish I could afford to do a steel plate drive....

Whats the thoughts of the community?
Call the move off, double up the plywood, or go ahead as planned?

Cheers!

macds said:

Well, hopefully the experienced rigger\engineering types can help me out here.

Im moving a 10000lb machine in this weekend using a 15000lb forklift (25000lb actual weight'ish).
I've done this 4 times now, and under normal circumstance, its a no brainer for me.

The variable this time is that weve had non stop rain for a week, and my 24" of "A" gravel is completely saturated.
What i normally do, even with dry gravel is lay down sheets of 3/4" fir plywood for the fokrlift to drive on.
I always get an indoor tire machine, so the plywood is to be nice to the tires, and man.... get one of those pigs stuck once.... trust me...

My concern this time around, is with the saturated base, will that 3/4 plywood stand up? Or is it going to flake out on me, leaving me with a bastard of a situation?
I wish I could afford to do a steel plate drive....

Whats the thoughts of the community?
Call the move off, double up the plywood, or go ahead as planned?

Cheers!

Click to expand...

"Gravel" is a pretty broad term. How thick, how consistent the gradation, is it locked with mineral fines/crusher-dust, what is under it, was that soil stabilized and compacted, how well compacted was the gravel when placed, how long ago, what prior wet-weather experience.... etc.

"From a distance", I can tell you two inches of pea-gravel over untreated gley soil ain't gonna cut it, and would not even still be detectable if an attempt had been made to compact it. Here, compacted soil, 9" to 12" proper gradation, compacted in 2-inc lifts, penetration Macadam style, 15,000 lb FL only makes surface mars when steered overly sharply.

Also, 'saturated' is not on the menu. Well-drained. 'waterbound', the penetrated with asphalt all but the last lift.

Otherwise, sorry - but I'm not close enough to walk it, let alone trench, core-drill or do a CBR test.

Prior experience, that specific area, is probably your best shot. May be the only one.

Places I rent all have "rough terrain" AKA "construction site" forklifts on-offer as well as yard and warehouse, I've been licensed on about four tribes of those, so I'd simply change my reservation if in doubt.

Plywood is for sheathing, roofing, crating, building plywood 'stuff'. A highway it ain't.

They do rent steel plates, too, y'know, usually same place as has the FL, same truck drop and recover. Not a huge deal.

If I follow your description correctly you will have a total weight of your forklift of 35,000#, most of which will be on the front tires.

I don't know what your call A gravel. Around here, gravel refers to round, smooth stones larger than sand. Being round, it doesn't pack worth a darn. Crushed rock is irregular in size with sharp edges and fractured surfaces. It will pack tightly. The fact you have gotten by with your project four times in the past suggests you have a well packed crushed rock drive.

One adds water to sand to lubricate the grains so they will move against each other to allow the sand to be packed. I suspect the rain will have supplied enough water to allow your rock to move.

I'd take Bill's suggestion of renting road plates or see if you can rent a heavy loader or rough terrain crane if your machine can be slung from a crane. Otherwise I'd wait for better conditions.

Monarchist, I do appreciate the response.
The rough terrain unit will not work due to my overhead clearance issue. Im putting a 103 inch peg through a 105" hole... mast is too tall on the off roaders.
As mentioned, the gravel is 24" thick "A" grade (lots of fines and sharp small stone to interlock). It was compacted with a 1100 diesel plate 3 years ago, and has seen a lot of traffic.
Base unfortunately is peat bog with a 1' base of pit run on top,. Its a never ending battle... and when the gravel fines get saturated, things get a bit spongy. When dry, there is zero movement. Its the lubricity the moisture adds that had me concerned, as it really cuts into locking forces of the fines.

Nobody around here rents riggers plates. Unless I hire a rigger for more than I paid for the machine.
I suppose thats why they "rig"?

The question I'm really asking is, will the shear strength of the plywood hold up to the counter fluidity of the gravel base. Im no roads engineer.

Wacky idea... what if i dig a hole on the low side of the drive grade and use a pedestal style sump pump to try to drain excess moisture from the gravel. I understand that capillary action will keep the gravel damp for a LONG time, but if i can get enough water off to prevent saturation....??

gbent said:

If I follow your description correctly you will have a total weight of your forklift of 35,000#, most of which will be on the front tires.

I don't know what your call A gravel. Around here, gravel refers to round, smooth stones larger than sand. Being round, it doesn't pack worth a darn. Crushed rock is irregular in size with sharp edges and fractured surfaces. It will pack tightly. The fact you have gotten by with your project four times in the past suggests you have a well packed crushed rock drive.

One adds water to sand to lubricate the grains so they will move against each other to allow the sand to be packed. I suspect the rain will have supplied enough water to allow your rock to move.

I'd take Bill's suggestion of renting road plates or see if you can rent a heavy loader or rough terrain crane if your machine can be slung from a crane. Otherwise I'd wait for better conditions.

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I fully agree with you. This mushy crap has me concerned. "A" gravel here is what they use for road building. I suppose a better term would be 3/4 crushed.
I do know that it turns to mushy crap in no time once its wet. Parking my 1 ton non dually will leave divits in a matter of minutes, and thats only 4500KG.
Trying to think ahead so as to avoid getting myself into a seriously poor situation.

I have contacted my local roads engineer for his opinion, but I'm willing to wager that common sense will prevail

macds said:

Monarchist, I do appreciate the response.
The rough terrain unit will not work due to my overhead clearance issue. Im putting a 103 inch peg through a 105" hole... mast is too tall on the off roaders.

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Hear yah. Different venue. VA DOT "may" be equivalent, because the Laws of Physics are. Our probable is called '21A'. IRC a 3" gradation right down to crusher dust, so it does compact well, and 24" - probably dictated by Canadian winters - sounds good, so long as it is A) WELL DRAINED, which 'saturated' puts the lie to, and was B) properly compacted in 'lifts' not overly optimisticly thick when placed.

The problem with not being well-drained, and all-year-every-year is that the soil under it goes straight to Hell in a mudpie, even if the soil itself would have had relatively high load-bearing and trafficability in its own right at lower moisture content.

Read on.

Base unfortunately is peat bog with a 1' base of pit run on top,. Its a never ending battle... and when the gravel fines get saturated, things get a bit spongy. When dry, there is zero movement. Its the lubricity the moisture adds that had me concerned, as it really cuts into locking forces of the fines.

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Prehistoric peat-bogs are the bane of our existence, even a hundred feet down.

Basically, you are f****d and already know how and why.

If you cannot rent steel plates or wait for a month of drought, buy the plate, have holes burned for chains, place with the FL as you walk it to the load.

Raw steel of that sort isn't all that costly if you have a source that can deliver. We do, here. Also a recycler that sells used plates from major projects after their contractors wrap up and go off to the next job. Usually somewhat bent ones, but BFD.

So - not riggers - heavy construction sites, MAJOR road-builders who break down and sell-off at completion. Those in routine repair and maintenance keep an arsenal of their own plates stashed.

The question I'm really asking is, will the shear strength of the plywood hold up to the counter fluidity of the gravel base. Im no roads engineer.

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Doubtful, but maybe. This ain't no 4,000 lb mini-FL nor load, and the worry as to Forklift TIP OVER to the side is far worse than getting frame-deep straight down..

I'd place timber grillage if I had no steel, but that eats way more of your overhead clearance.

Wacky idea... what if I dig a hole on the low side of the drive grade and use a pedestal style sump pump to try to drain excess moisture from the gravel. I understand that capillary action will keep the gravel damp for a LONG time, but if i can get enough water off to prevent saturation....??

Click to expand...

Not 'wacky'. Undersized.

Google 'Stang wellpoint'. What Dad used 1953 to save a major power substation stupidly built on a peat bog, also what he game-planned fixing the Leaning Tower of Pisa 40 years before they finally DID it. FREEZING the soil at depth and upward to create a wall is also involved.

It is the PEAT below it you have to drain, and it is a non-trivial exercise, especially if there is a subsurface source of more water that extends beyond your small patch.. as it will do.

Your area almost certainly publishes DETAILED soils geology online - I have used Canadian sources for that before.

If you could afford to cut-off water ingress, actually drain the peat, it would then compress, stabilize, soil and gravel above drop a fraction. This needs more time than you have.

The big bucks are in diverting water ingress and draining stuff over a wide area under structures you do not control, so "faggedaboudit" as to permits. You cannot afford the liability cover if even you could afford the planning, etc.

Get thee steel...

OR .. .pay attention, there may be a quiz later....



.. do a safer-site-nearby / terminal transfer to a rollback so you have the overhead clearance back in your favour.

No forklift == no mast.

Then you can timber a 'roadway' for the roll-back's wheels, add THIN steel plate for where the equipment comes off the rollback and onto rigger's skates for the last-leg.

Hands down, now... I'd do it that way.

I seriously doubt 3/4 plywood is going to hold up. You better either find you some heavy steel plates or hire a rigger.

I know the above two options are expensive but things could get much more expensive if you drop the machine and then have to hire a wrecker to get the forklift out, and to top it all off, the machine still isn't in the building.

There isn't a easy solution here.

m16ty said:

I seriously doubt 3/4 plywood is going to hold up. You better either find you some heavy steel plates or hire a rigger.

I know the above two options are expensive but things could get much more expensive if you drop the machine and then have to hire a wrecker to get the forklift out, and to top it all off, the machine still isn't in the building.

There isn't a easy solution here.

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Forklift rental, drop and recover fee isn't that different from rollback callout, transfer made at a terminal, NO forklift.

For any 'revenue' enterprise, the cost of transport, rigging, inside installation, power, etc is amortized right in with the price of the machine itself.

Smallholder, retiree, hobbyist? Can't afford jacks or better for rigging, can't really expect to be dealt a hand.

TOTAL cost of the 'go-fetch' here is typically two to four times the cost of the machine, and I still wouldn't WANT a forklift of my own. Renting lets me get a different type each go fit each job. I don't get old ones with bad brakes, I have new ones and no need to store them.

Even with having the yard half done, I still deal with this problem.

IMHO with a smooth tire forklift, you have no chance, plywood is strong, but that's asking a lot.

I'd hate to go through all the trouble of lining up trucks, equipment etc and have something get stuck and make a big mess.

I moved a 12,000lb lathe out of a mud hole (yes a literal mud hole....) with a 25,000lb forklift. Got the forklift stuck pretty much up to the axles and it wasn't even all that wet of a day.

Tied on to the butt of the stuck forklift with a Case 930 (90hp tractor), I was in the forklift and had a helper on the tractor. Was able to get out, but not a huge hurry to back in again.

Had to get the machine moved, so started throwing dunnage in the hole. Stared laying stuff in the ruts, then a layer perpendicular to that, in order to spread the weight out once the first layer sunk in, then a layer parallel to the first layer as a "road".

Worked well enough to get the machine moved.

What about renting a yard forklift, or better yet a big front end loader, to get the machine off the truck, then hand it off to the other forklift in the door way?

Got any scrap yards close to you? I have one two miles from me that is ticked pink to sell all the I beam and road plates I want for $.25/lb.

103" machine in a 105" hole doesn't leave a lot of room for forks. My 25k machine has light forks at only 2.5" thick, should be 4".

I'd say you are hosed on gravel. steel plate or concrete pavers/ brick. you need something to spread the load that stands up to 20k. Even channel iron for the wheels to roll on might do it.

Will it fit on one of these?
Tandem Axle HGL | Drop Deck Depot
If so, save the forklift for the inside part of the show... or just use the trailer all the way back to destination. Double/triple up your lumber under the wheels for the approach to the garage, and you should be fine.
I have seen these trailers at Herc (formerly Hertz Equipment Rental) and a local safe company had a gooseneck version. Your options may be different in the frozen north.

Good thing is it shaves about 15,000 lbs. from the equation.

Chip

I think Monarchist might have hit on it! A ROLL OFF container-dumpster.

he said rollback, we usually call 'em dumpsters around here. a skip in the UK. used for garbage, bulk material waste, construction and roadwork material, you know.

the rig is common, easily rentable as truck and container for a few hours to a day, and if a triple axel rig, I bet that would spread the load enough to get an exceptable PSI loading on your ground conditions (possibly), as you are spreading it out on 10 or 12 large truck tires.

might need a deck plate for the landing area, but the hardest part could be securing the machine during the "tip off" as the container is rolled off the rig. if you have a construction company that is approachable in your area, they may have a bin that they modified for hauling equipment with tiedown points welded in.

...HMM.. on review, the guys who usually sling beat-to-crap bobcats, bins of rocks, and trash might not be the guys you want... nevermind!

chip's idea is good, but the PSI ground load on the small trailer tires, combined with low ground clearance, would probably be a no-go on that. (might work with enough plywood..)

cheers, let us know how it goes, and good luck!

I've heard of peat bog but never actually seen it. Sounds like some nasty stuff. You should be able to eventually put enough plywood down ( staggering the joints), but not knowing the exact situation, I don't know how much. That can get pretty expensive too, depending on how far you have to go.

I don't know your area but here in the big city there several places that rent road plates. The big rental outfits like United or Sunbelt may have them and we have several independents here who rent them as well. I have paid $50 bucks a week each for plates before including delivery but I would be surprised to see prices that low elsewhere.

You say an off road machine has to tall of a mast. When thinking off road I always think of a variable reach forklift rather than a conventional one. 12K machine will get a lot of things moved. They easily get themselves unstuck unless you really do some stupid sh#%t

If you don't already have the plywood on hand I might suggest using the engineered subfloor board that is moisture resistant. This stuff is designed to stand up to weeks of weather while the rest of the building is being framed.

If you do already have the plywood on hand I might suggest applying some oil finish on the side that will face the gravel now. As long as it's exterior plywood I don't see an issue being in contact with wet gravel for a few hours, even without the finish.

Last spring I moved an 18K lb machine on the forks of an H360HD a few hundred feet across saturated 3/4 minus gravel. The 50K pounds or so on the drives pushed the driveway down a few inches. The four front tires on that lift were huge though. I turned around in a muddy plain dirt area with the empty machine and it didn't get stuck.

The 16' mast of the H360 won't fit inside many buildings though. Telehandler sounds like a good plan.

Next time you build a driveway start with geotextile fabric then fill with 4" minus road base then top with your 3/4. The fabric makes all the difference in the world for long term use.

Garwood said:

Next time you build a driveway start with geotextile fabric then fill with 4" minus road base then top with your 3/4. The fabric makes all the difference in the world for long term use.

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Totally right.

Thats what I did under my yard. A layer of road base, capped with a layer of 3/4" fines.

Its really does make a diffrence. Takes a little while to settle and compact, but its the way to go.

Sounds like you need a telehandler style forklift. We used to run an early Lull in lots of soft stuff with the big tires on it. The wildest thing we did on one job was rescue the GC's 75 ton crawler crane when it got stuck in the mud. When we couldn't make any motion with the 4 wheel drive, the boss dug in a pallet on the forks and extended the boom to push the fork back and drag the crane. Repeated as necessary and had the crane out and moving within an short time.

alskdjfhg said:

Totally right.

Thats what I did under my yard. A layer of road base, capped with a layer of 3/4" fines.

Its really does make a diffrence. Takes a little while to settle and compact, but its the way to go.

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+1. I have an area that's 3/4" only and it does depress under heavy loads when saturated. Areas built with 3s and 4s on the bottom don't do that.

If you can get asphalt millings, try putting a layer of that on top of your gravel. Millings compact hard and knit together, and water will run off pretty much like real asphalt. After a few months of sun exposure even snow plowing won't move them, you need a bucket with teeth to penetrate it.