Making use of temporary cohesion in clean sand
Making use of temporary cohesion in clean sand
(OP)
I have an engineer friend designing an addition to a town hall where an addition with basement will be built next to an existing building. The existing building sits on an old shallow depth stone foundation with 2 foot crawl space.
Those floor joists run parallel to the shallow foundation. The foundation therefore has very light load on it.
Soil is clean sand with maybe a 30 degree angle of repose when dry. When damp it stands at 45 degrees or better, but only due to that temporary cohesion.
He would like to place the new 8 foot depth basement wall about 6 feet out from the old foundation.
The client has very little in the budget for tie-backs, sheeting, etc. Short of placing the new basement wall well out from the old building, he is searching for a cheap way to do it closer.
This will be bid, so his plans may not be able to show "how to do it". The wall may be either CIP concrete or block.
Has anyone had experience where you make use of temporary cohesion in damp sand for short term construction with an unretained steep earth slope next to the forming for the basement wall? Admittedly OSHA has to be happy with it.
Those floor joists run parallel to the shallow foundation. The foundation therefore has very light load on it.
Soil is clean sand with maybe a 30 degree angle of repose when dry. When damp it stands at 45 degrees or better, but only due to that temporary cohesion.
He would like to place the new 8 foot depth basement wall about 6 feet out from the old foundation.
The client has very little in the budget for tie-backs, sheeting, etc. Short of placing the new basement wall well out from the old building, he is searching for a cheap way to do it closer.
This will be bid, so his plans may not be able to show "how to do it". The wall may be either CIP concrete or block.
Has anyone had experience where you make use of temporary cohesion in damp sand for short term construction with an unretained steep earth slope next to the forming for the basement wall? Admittedly OSHA has to be happy with it.





RE: Making use of temporary cohesion in clean sand
Also, the weight of the wall itself may be significant even though the joists run parallel to the wall. Sheeting probably is not appropriate for supporting the building.
Even though the new wall is 8 feet away, you will still need extra space to build, backfill, and waterproof the new wall. Therefore, your 6 feet may be reduced to as little as 3 feet. It looks like you should underpin the existing building, if allowed.
Make sure that the wall along the excavation is properly supported against lateral movement. A free-standing wall could be trouble.
Just because the client has very little money in his budget for tiebacks, sheeting, etc., that does not mean you should accept his problem and risk.
RE: Making use of temporary cohesion in clean sand
f-d
¡papá gordo ain't no madre flaca!
RE: Making use of temporary cohesion in clean sand