BJT
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Post by BJT on Mar 18, 2021 20:59:39 GMT -6
What’s everyone’s thoughts on what’s better? Are screw piles going to be the new thing, better than cement? Tough to find an unbiased answer.
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Post by meskie on Mar 18, 2021 21:14:14 GMT -6
If the guy putting in screw piles knows what he is doing I’d say they are better. You need to keep going as deep as you need till they get to a certain torque. Lots of guys only put in one length with screw piles. With cement ones they generally only go to a certain depth no matter what soil they are in.
I had a long conversation with an engineer about them when I built my house. Every situation is different is what he told me. We dug the basement 4’ in the ground and had water coming in the wall at 2’. Could hardly walk in the bottom it was so soft. Put screw piles under the footing and it hasn’t moved a bit in 10 years. Engineer also had us fill the screw piles with cement so I guess it was both types we used.
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BJT
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Post by BJT on Mar 18, 2021 21:54:39 GMT -6
I have heard similar stories, what’s the idea with filling with cement ?
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nvw
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Post by nvw on Mar 18, 2021 21:58:10 GMT -6
My guess is if the piles rust out the cement is still there.
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Post by SWMan on Mar 18, 2021 22:09:25 GMT -6
Could be that they don't rust from the inside from having air/moisture inside.
Colony next to me is making screw-piles constantly, so there is a lot of people using them. They built like a 200'x600' steel building on screw piles, I watched some go in and there was vertical ones and angled ones as well, then they welded them together at the top and made a plate to mount the building columns. It's all quite the setup, they usually don't cut corners.
It would be hard to beat a 30-36" cement pile though, that's what I put under my tower, scale and overhead bins. I don't regret that one bit, cost 11K for 18 piles and I think we poured 7 yards of cement down each hole...
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BJT
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Post by BJT on Mar 18, 2021 22:34:32 GMT -6
Swman, how deep were those piles ?
Makes sense to fill with cement and keep them sealed.
I would think a galvanized pipe should last for a very long time underground 🤷🏼♂️
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Post by SWMan on Mar 18, 2021 22:42:31 GMT -6
They were 20-24' deep with a flare on the bottom that increases footprint and resists frost-jacking. Also got me down to some of the heaviest gray clay I have ever seen, I kept a ball of it and it dried like cement!
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nvw
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Post by nvw on Mar 19, 2021 8:29:03 GMT -6
They were 20-24' deep with a flare on the bottom that increases footprint and resists frost-jacking. Also got me down to some of the heaviest gray clay I have ever seen, I kept a ball of it and it dried like cement!Sounds like our soil, some of it is on the top. |
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Post by dookiller on Mar 19, 2021 9:37:43 GMT -6
They were 20-24' deep with a flare on the bottom that increases footprint and resists frost-jacking. Also got me down to some of the heaviest gray clay I have ever seen, I kept a ball of it and it dried like cement! Where I live you don't need to drill vertically to find that gray clay. A couple of our fields have that clay stop a tractor in its tracks if you spike to deep. First yr a Mennonite farmed a 1/2 section they had just purchased they heavy harrowed it multiple times when damp. Packed the crap right out of it and they had to seed it moving way slower and shallower than ever before. Their big tractor became under powered and small instantly. Lesson learned the hard way on clay. It requires a completely different choice of equipment and you learn to live with the straw being your friend. Those roots in the ground are the difference between having a lump fest or a nice crop. Air wont get to the roots and a damp yr just wrecks yield. Lots of screw piles being used here too now. I think cement is likely a better longevity choice though. Rust is inevitable. Cement will be at its strongest yrs down the road where steel starts degrading from rust instantly. Truth be told steel will likely outlive our needs but the grandkids might appreciate cement down the road. |
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Post by meskie on Mar 19, 2021 9:43:43 GMT -6
If they are sealed in the ground steel seems to take a long time to rust. If it’s not exposed to air rust has a hard time forming.
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Post by skfarmboy on Mar 19, 2021 21:11:39 GMT -6
My though is that for vertical loads a properly engineered screw pile is fine. The problem I see see is lateral loads (wind pressure on the side wall) a 4 inch pipe is not going to hold the bottom of the wall in place under a high wind load, imo. I assume that would be why the colony installed angled screw piles and welded them to the vertical piles at the top. The other situation that would anchor the top of the screw piles from lateral movement would be a cement floor.
I considered screw piles when I put up my steel framed cold storage building, but went with concrete piles for the above reason.
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rcyung
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Post by rcyung on Mar 19, 2021 21:42:43 GMT -6
The screw pile manufacturers and installers say they are better. Must be true lol. In all seriousness consult an engineer and do a cost comparison. There’s always more than one way to accomplish the end result. I worked on this building in 2015 that used screw piles and the next year , just a few blocks away, we worked on a similar building that used wooden piles driven in. Just for interest’s sake I’ve posted these pictures. As Meskie mentioned a certain torque , I thought you’d be interested in seeing these piles torqued until they twist like a liquorice . 8 inch pipe. You can see it in the cutoff lying on the ground and the one in the background far right.  |
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BJT
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Post by BJT on Mar 20, 2021 7:25:56 GMT -6
My though is that for vertical loads a properly engineered screw pile is fine. The problem I see see is lateral loads (wind pressure on the side wall) a 4 inch pipe is not going to hold the bottom of the wall in place under a high wind load, imo. I assume that would be why the colony installed angled screw piles and welded them to the vertical piles at the top. The other situation that would anchor the top of the screw piles from lateral movement would be a cement floor. I considered screw piles when I put up my steel framed cold storage building, but went with concrete piles for the above reason. What type of steel building did you put up? |
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BJT
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Post by BJT on Mar 20, 2021 7:27:39 GMT -6
The screw pile manufacturers and installers say they are better. Must be true lol. In all seriousness consult an engineer and do a cost comparison. There’s always more than one way to accomplish the end result. I worked on this building in 2015 that used screw piles and the next year , just a few blocks away, we worked on a similar building that used wooden piles driven in. Just for interest’s sake I’ve posted these pictures. As Meskie mentioned a certain torque , I thought you’d be interested in seeing these piles torqued until they twist like a liquorice . 8 inch pipe. You can see it in the cutoff lying on the ground and the one in the background far right. View Attachment8” pipe twisted like that should hold something in the ground. Pricing I’m getting for a screw pile vs 24’ deep cement pile is 40% for cement. So not a big difference in the cost of the whole building. |
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rcyung
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Post by rcyung on Mar 20, 2021 8:14:47 GMT -6
I’ve never been involved with concrete piles any more than 12 feet deep. Without knowing your soil etc you could hit water or something else down there. The site in the photos had a few boulders down deep. The company had to bring in a drilling rig to bust them up then proceed with installing the pile. The other site with the wooden piles ended up hitting a solid brick and concrete structure from an old sawmill site dating back to the early 1900s. They ended up doing some re-engineering for two piles. I don’t want to scare you or anything but just shows how things can unexpectedly change. I’m sure your experience will be good. Just be sure your cost comparison includes any pile caps etc. For example if you put screw piles then fill them with concrete. Your building type may not require that though.
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