Septic Tank Driveway

[MikeD74T]

Planking over a septic tank that down 2 1/2' is no different than crossing soft ground. Dig in doubled 2x12x8' PT in the tire tracks & drive over them. You're not talking concrete trucks here. The planks will never see more than 1/2 the cars weight. 2500 lbs ( a full sized pickup) distributed over 16 square feet won't damage your tank. I have put 10 wheelers of crushed stone over triple plywood on a lawn with no visable damage.

A lot of the "fell thru the tank" stories come from the old steel tanks. The cover was like a drum & would rust thru. I know a lady that was launched off the toilet when her husband drove a loaded dump truck over their steel tank. The bending cover worked like a giant plunger, in reverse. She made him clean the bathroom. MikeD74T

 

[DanD78]

I think if you would do the math and pour a 4" slab over the entire area you would find that the concrete weighs less per square foot than your car and if you do drive over it the weight will be spread over the area of the slab not concentrated in the tire foot print.

As far as the access hole use a 20" plastic pipe as a sleeve between the top of the tank and the bottom of the slab but so no weight gets transfered to the tank. Make a steel lid to fill the hole in the drive slab.

You might want to ask an engineer instead of a bunch of guys that think they know best, my self included.

Dan

 

[MrWoodChips]

While I can think of worse situations, the concept of several tons of wet concrete mixing with a thousand or more gallons of sewage, all right in my backyard gives me the willies.

This does suggest one good idea. ANYTHING you do is best done only after you have the tank pumped.

John

 

[Pirate]

You might want to ask an engineer instead of a bunch of guys that think they know best, my self included.

Dan

Ya know, I didn't even think of that. I had an engineer out once when I had a sagging floor. Structural guy. I'll have to call him about this too. Not sure if he can provide any advice though unless I remove all the cover and totally expose the tank top. I'm not looking forward to that since I just pumped it.

 

[JoeL4330]

If you are willing to put a slab in, then the riser doesn't need to bear any weight at all ...think manhole cover...the riser can "slip by" the slab ...a little extra rebar in the slab to hold the "manhole cover". Of course, I'm no engineer

 

[Eagleview]

A reinforced slab over the tank would work , but if the tank or fittings fail at any time it will be a major ordeal to replace it or fix the fittings . I would fill it in with good road base gravel and put a new tank and absorbtion trench in a more suitable location . It would be no more expensive than the concrete slab and is a brand new system .

 

[tommu56]

Think of a man hole in the street you drive over them all the time there at wiring vaults under there too that I've seen some a good 8'W 12'L and 8'deep

I would call a precast company explain what you what you have and ask them for recomendation they might even tell you what the load design for them is.

or get them to make a precast piece to sit on the edges of the tank no load in the center were the cover is. make some sort of slip joint to on tank outside sitting on new bridge/cover with a manhole rings laid up to grade on the bridge with a manhole cover at grade.

tom

 

[Pirate]

Lots of great ideas. I really can't move the tank. I'm on top of a small ridge. No yard to speak of. Front yard is only 20 feet from porch to woods/steep slope down. Back of house is driveway then steep slope down. You get the idea. If I were to move tank, I would have to move entire system because I would end up putting the tank where the drain field is now and then run a line down a hill to a small holler where I think I could put the drain field. Lots of "I thinks" in this mess. It would be cheaper at this point to cap the tank with nice thick slab and stick a riser in. I like the idea of having a manhole cover supported by the slab and not on the riser. You can see the lower garage in this http://s215.photobucket.com/albums/cc53/pirateghostabc/3 May 2008/?action=view&current=IMG_0013.jpg You can look at other pictures if you are bored while you are there.

 

[guyrj33]

When our system was installed we had a heavy duty cover put on, it's strong enough to drive a truck over. Perhaps you can replace the cover on your tank. An engineer might be able to look at your cover and tell you how much weight it can carry.

 

[Pirate]

When our system was installed we had a heavy duty cover put on, it's strong enough to drive a truck over. Perhaps you can replace the cover on your tank. An engineer might be able to look at your cover and tell you how much weight it can carry.

I'm worried about the tank itself. I already replaced the "cover" with 1/2 steel plate. I believe you are talking about the small access cover usually only a couple of feet across, right?