ᐅ Cistern placed directly next to the construction access road – risk of damage?
Created on: 30 Oct 2020 09:50
T
Tolentino
Hello dear forum members,
the demolition has now been carried out at my construction site (https://www.hausbau-forum.de/threads/lage-stadtvilla-oder-efh-auf-500-m2-rechteck.33505/post-442751).
In addition, a temporary access road for construction vehicles has been established, which unfortunately ends directly at an (empty) (PE) cistern (https://www.hausbau-forum.de/threads/lage-stadtvilla-oder-efh-auf-500-m2-rechteck.33505/post-442845).
My neighbor and co-builder (but with his own house located at the rear of the overall property) is now concerned that the cistern could be damaged if a 40-ton truck drives all the way down the access road. The load is said to be distributed at a 45° angle downward, according to our site manager’s explanation. This would mean that part of the cistern would definitely be subjected to some of the load. There is maybe about 1 meter (3 feet) of soil between the access road and the cistern. The cistern measures approximately 2 x 1.5 x 1 meter (6.6 x 4.9 x 3.3 feet) and is installed vertically, with its longest side buried underground.
Is his concern justified? Would it be enough, for example, to simply fill the cistern? Or would it be better to dig it up and relocate it? Here, I am worried that the access road at the back might then become unstable, even if we refill the hole. We probably won’t be able to compact it properly (the neighbor wants everything done with excavation and loading, EL).
Does anyone here have experience in civil or geotechnical engineering, or could even calculate this? What data would be needed for that?
the demolition has now been carried out at my construction site (https://www.hausbau-forum.de/threads/lage-stadtvilla-oder-efh-auf-500-m2-rechteck.33505/post-442751).
In addition, a temporary access road for construction vehicles has been established, which unfortunately ends directly at an (empty) (PE) cistern (https://www.hausbau-forum.de/threads/lage-stadtvilla-oder-efh-auf-500-m2-rechteck.33505/post-442845).
My neighbor and co-builder (but with his own house located at the rear of the overall property) is now concerned that the cistern could be damaged if a 40-ton truck drives all the way down the access road. The load is said to be distributed at a 45° angle downward, according to our site manager’s explanation. This would mean that part of the cistern would definitely be subjected to some of the load. There is maybe about 1 meter (3 feet) of soil between the access road and the cistern. The cistern measures approximately 2 x 1.5 x 1 meter (6.6 x 4.9 x 3.3 feet) and is installed vertically, with its longest side buried underground.
Is his concern justified? Would it be enough, for example, to simply fill the cistern? Or would it be better to dig it up and relocate it? Here, I am worried that the access road at the back might then become unstable, even if we refill the hole. We probably won’t be able to compact it properly (the neighbor wants everything done with excavation and loading, EL).
Does anyone here have experience in civil or geotechnical engineering, or could even calculate this? What data would be needed for that?
Hmm. I think we’re talking past each other.
I’ll try with a sketch. As you can see, the construction road is actually a bit short for the rear building plot. However, the site manager can work with that. Of course, this also means that the construction road must be accessible all the way to the end. We can’t block off any more sections.
The questions now are:
- Could the cistern be damaged? How likely is that?
- Could the construction road be damaged (sink) if the cistern remains in place?
- Is simply filling the cistern with water enough to sufficiently reduce the risk of both?
- Isn’t there an even greater risk to the construction road if we excavate it ourselves, remove it, and refill it?
Thanks and best regards,
Tolentino
I’ll try with a sketch. As you can see, the construction road is actually a bit short for the rear building plot. However, the site manager can work with that. Of course, this also means that the construction road must be accessible all the way to the end. We can’t block off any more sections.
The questions now are:
- Could the cistern be damaged? How likely is that?
- Could the construction road be damaged (sink) if the cistern remains in place?
- Is simply filling the cistern with water enough to sufficiently reduce the risk of both?
- Isn’t there an even greater risk to the construction road if we excavate it ourselves, remove it, and refill it?
Thanks and best regards,
Tolentino
N
Nice-Nofret30 Oct 2020 11:04What purpose will the cistern serve in the future? What material is it made of? If it is no longer needed, is there any reason against filling it with soil?
This is a PE cistern, which is intended to continue being used as a cistern in the future. The location is actually very good. It is positioned on the boundary between our properties, and we would both drain at least part of our roofs into it.
Moving it later on is not a problem in itself. Having it done professionally is more of a financial issue. At least my neighbor always wants to do a lot of the work himself, and since we are going to use it together, I feel a bit pressured to join in.
I just don’t know if moving it now might be even riskier. However, I have already asked the site manager for his opinion on what would be best.
Moving it later on is not a problem in itself. Having it done professionally is more of a financial issue. At least my neighbor always wants to do a lot of the work himself, and since we are going to use it together, I feel a bit pressured to join in.
I just don’t know if moving it now might be even riskier. However, I have already asked the site manager for his opinion on what would be best.
Update: The site manager believes the main risk is more likely accidental driving over the tank by trucks, construction vehicles, or cranes.
Once the cistern is filled, the lateral pressures shouldn’t be that severe.
Nevertheless, upgrading it would be advisable simply because no one can constantly monitor to ensure that no one drives over the cistern.
He also trusts that we can manage the expansion, backfilling of the hole, and compaction with a hand tamper ourselves in EL.
Question: What is the approximate weight of a PE cistern with about 3 m³ (3.9 yd³)?
Once the cistern is filled, the lateral pressures shouldn’t be that severe.
Nevertheless, upgrading it would be advisable simply because no one can constantly monitor to ensure that no one drives over the cistern.
He also trusts that we can manage the expansion, backfilling of the hole, and compaction with a hand tamper ourselves in EL.
Question: What is the approximate weight of a PE cistern with about 3 m³ (3.9 yd³)?
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