Alternative to Alturnamats

I put loose sheets of plywood (mostly picked from roofers dumpsters) under the alturnamats for real sensitive areas, like pool decks etc.. mostly focus on the edges...
I never heard of mats being less effective at weight displacement either..... might have something to do with the local geography.. soft soil in NJ or something..

DO they make mats with the traction bars on one side and smooth on the other? that would be ideal for the skid steer...
 
For getting on and off driveways/sidewalks your best bet is to have the tire/track coming down on the paved surface and lifting off at the end. Putting a mat/plywood across the edge isn't going to help much. Putting a mat(s) down on the non paved surface butted and higher than the edge of the pavement takes some of the load off the weakest point, the edge.


Do the smooth mats slip and slide on the ground?
 
limbcontrol said:
We have 20 alturnamats. They do not offer the weight displacement plywood offers. Alturnamats will still leave indents in lawns and crack driveways. Sure they last longer than plywood, but I'd rather buy more plywood than buy a new driveway.
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I couldn't agree more. We run 4x4 plywood as easier to move and make turns on a plywood road. Periodically I get clients to pay for them if it is them that needs an elaborate set up. Never had a complaint. Keep them stacked and covered with a tarp and they won't get heavier.
 
I buy 3/4 inch pressure treated plywood. We rip it down the middle to give us 4x4 sheets. Works great, doesn't get heavier with moisture and doesn't rot. We just store them out in the weather. Way cheaper than alturnamats.
 
limbcontrol said:
We have 20 alturnamats. They do not offer the weight displacement plywood offers. Alturnamats will still leave indents in lawns and crack driveways. Sure they last longer than plywood, but I'd rather buy more plywood than buy a new driveway.
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A 4x8 plywood has the same 32 square footage as alturna mats, the later being slightly heavier. I can't seem to figure out how plywood would displace weight better. I would assume plywood my have less deflection than plastic under heavy loads maybe?
 
My thoughts on how plywood could be better, is plywood is in layers (and I think grain goes different directions). So each layer displaces the weight in different directions therefore diffuses it more.

Where as the mats are solid. Pressure will just radiate out evenly without transition to other directions

But I've never used the mats...or put a crane on either...just guessing
 
http://www.alturnamats.com/faq.php

"Pages could be written on this question, AlturnaMATS have recently conducted testing. Our first test is called Flexural Properties ASTM D790 measuring the deflection ration or flexural strength at specified strain levels. Following are the test results below conducted at ambient room temperature.



FLEXURAL PROPERTIES OF ALTURNAMATS AND VERSAMATS
Scope: the flexural test measures the force required to bend a beam under three point loading conditions. The data is often used to select materials for parts that will support loads without flexing. Flexural modulus is used as an indication of materials stiffness when flexed.

TEST SPECIMEN; 12' x 12' x 1/2" (30.48 CM x 30.48 CM x 1.27 CM)

This is a comparison between different mats offered by AlturnaMATS and plywood. The following is a laboratory test and, because of such drastic environment changes from job site to job site, these should be considered only reference point numbers.



PRODUCT DEFLECTION

PLYWOOD .098(2.4892MM) @ 50 PSI
STANDARD ALTURNAMATS .045(1.143MM) @ 50 PSI
VERSAMAT (VERSA TREAD UP) .054(1.3719MM) @ 50 PSI
VERSA MAT (VERSA TREAD DOWN) .049(1.2446MM) @ 50 PSI

Results indicated above clearly shows that AlturnaMATS have twice the deflection ratio characteristics of 5/8" plywood. Adding a moisture factor into this test and plywood deflection drops another 50%, where in the case of polyethylene moisture and water have no effect."
 
The more rigid the material is (same as bridging), the better it will spread the load into the ground... it's just physics.
 
Lumberjack said:
The more rigid the material is (same as bridging), the better it will spread the load into the ground... it's just physics.
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Actually I disagree with that. A I-beam made out of plywood is smaller, and lighter, then one made of steel, but is still comparable in strength...due to the layering.

True a sheet of plywood, just supported by both ends, will bow more then a mat. But that doesn't mean it displaces the weight less, it just transfers it throughout its total area.

Something stringy is often stronger then something rigid...like hickory trees, yes etc
 
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climbhightree said:
Actually I disagree with that. A I-beam made out of plywood is smaller, and lighter, then one made of steel, but is still comparable in strength...due to the layering.

True a sheet of plywood, just supported by both ends, will bow more then a mat. But that doesn't mean it displaces the weight less, it just transfers it throughout its total area.

Something stringy is often stronger then something rigid...like hickory trees, yes etc
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There is no way a plywood I beam would be smaller, lighter, and stronger than a steel I beam, no way possible.

The more rigid the mat is the more the weight transfers evenly across the mat. The more flexible it is, the more the load distribution will be concentrated under the point of loading.

Example, lay a piece of plywood on the ground, set an outrigger up on it. Do the same with a 1" thick piece of steel. Which edge can you pick up? The plywood, because it's more flexible. Crane outrigger pads will put an indention in the ground around the edge. A more flexible pad wouldn't make an indention, but there would be a depression that increased in depth as you move towards the outrigger's loading point on the mat.
 
Lumberjack said:
There is no way a plywood I beam would be smaller, lighter, and stronger than a steel I beam, no way possible.

The more rigid the mat is the more the weight transfers evenly across the mat. The more flexible it is, the more the load distribution will be concentrated under the point of loading.

Example, lay a piece of plywood on the ground, set an outrigger up on it. Do the same with a 1" thick piece of steel. Which edge can you pick up? The plywood, because it's more flexible. Crane outrigger pads will put an indention in the ground around the edge. A more flexible pad wouldn't make an indention, but there would be a depression that increased in depth as you move towards the outrigger's loading point on the mat.
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Not plywood, but made the same way...layers of wood glued together

http://www.ehow.com/info_12176125_steel-beams-vs-laminate.html#page=0

" Laminated beams are stronger and more versatile than other natural wood used in the construction process. On a pound-for-pound basis, Glulam is also stronger than steel, according to the Engineered Wood Association. This strength makes laminated beams a logical choice for various types of projects. "


Lumberjack said:
There is no way a plywood I beam would be smaller, lighter, and stronger than a steel I beam, no way possible.

The more rigid the mat is the more the weight transfers evenly across the mat. The more flexible it is, the more the load distribution will be concentrated under the point of loading.

Example, lay a piece of plywood on the ground, set an outrigger up on it. Do the same with a 1" thick piece of steel. Which edge can you pick up? The plywood, because it's more flexible. Crane outrigger pads will put an indention in the ground around the edge. A more flexible pad wouldn't make an indention, but there would be a depression that increased in depth as you move towards the outrigger's loading point on the mat.
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I realize I am muddy the water by bringing steel into the mix. And like I said, I've never use a mat or compared it to plywood of the same thickness...so I could be way off base.

I'm just saying the layers properties of plywood may be a factor in why some prefer plywood over the mats.

Another thought I had...I've never seen plastic or steel cribbing for leveling a crane...always seen wood blocks. Why is that?

Not trying to pick a fight, or say it is my way or the highway.
 
One issue is we are chasing multiple, intertwined relationships/issues. The first I think we need to agree on is if rigidity increases distribution of weight.


Above, I said that wood can't be smaller, lighter, and stronger than a steel I beam. Your link says the Glulam beams are stronger than steel by weight. If wood was stronger than steel, bridges and crane booms would be made from it. Also Glulam beams are only stronger than low strength steel, steel's strength (tensile) has a wide range, just like most materials.

When it comes to dispersing the load, rigidity is a huge factor. The 120T crane I work with uses steel plates, roughly4'x4'x1.5" thick to spread the load out on normal ground. Wood is used for levelling when required.


I'm not saying that plywood is worthless, only that according to the numbers put out by Alturna, 1/2" plywood is 1/2 as rigid as Alturna mats. It has to do with the modulus of elasticity. Another factor that affects rigidity is the section modulus and distance to the extreme fiber from the neutral plane.
 
That test was done by alturnamats, good marketing but not a conclusion that mats are best suited for all equipment at all job sites.. There is more to weight displacement(ground pressure) than measuring deflection of a material. I first started using alturnamats with our crane to go on driveways and cracked quite a few. Switched to 3/4" plywood and have been good. When you have a big crane that needs to go on a driveway mats do not work. When you need to take that same crane on grass alturnmats will flex and still leave big impressions. We switched over to 3/4" plywood and have been good. Our alturnamats we lay down for the skid loaders, spiderlifts and bucket trucks(only when ground is hard) since they serve that application well. Most others with big cranes on here, such as Marquis also lay out the ply. Why? Because there is less lawn, concrete or asphalt damage when using plywood
 
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