Alternative to underpinning
Alternative to underpinning
(OP)
Hello everyone,
I have a question regarding an underpinning. What is an alternative to the typical underpinning method ? An architect works on the project where they are adding an extra floor to the exist. residential building plus they want to deepen the exist. cellar of about 10 feet. There is no ground water expected at this level. There are adjacent buildings at both sides. The thing is that the neighbors do not want to agree on any underpinning. I am supposed to prepare the proposal for SOE design for this project. But before I do that, I'd like to find a solution. I was thinking about titan micropiles..But I have never done this before so I Am not sure how this works for cellar deepening with adjacent buildings around..? I know it works well for foundation remedies.. Does anyone have any solution/good didactic materials? I would appreciate every advice. Thanks!
I have a question regarding an underpinning. What is an alternative to the typical underpinning method ? An architect works on the project where they are adding an extra floor to the exist. residential building plus they want to deepen the exist. cellar of about 10 feet. There is no ground water expected at this level. There are adjacent buildings at both sides. The thing is that the neighbors do not want to agree on any underpinning. I am supposed to prepare the proposal for SOE design for this project. But before I do that, I'd like to find a solution. I was thinking about titan micropiles..But I have never done this before so I Am not sure how this works for cellar deepening with adjacent buildings around..? I know it works well for foundation remedies.. Does anyone have any solution/good didactic materials? I would appreciate every advice. Thanks!






RE: Alternative to underpinning
RE: Alternative to underpinning
Please remember: we're not all guys!
RE: Alternative to underpinning
SLTA - how would you excavate 10' below the existing foundation wall/slab in order to build a retaining wall? You mean narrow excavation and build the retaining wall in sections..? Thanks !
RE: Alternative to underpinning
Please remember: we're not all guys!
RE: Alternative to underpinning
RE: Alternative to underpinning
RE: Alternative to underpinning
RE: Alternative to underpinning
structSU10 - the existing cellar is around 10' below the sidewalk level. They want to go another 10' lower and add Subcellar at elevetation (bottom of excavation at around -20') There shouldn't be any headroom issue since as far as I know the exist. cellar slab is going to be knock down and rebuild.
I have a headroom issue with a different SOE project, very similar to this one, but the ground water is high and it is a landmark building, all exterior brick walls have to stay untouched so we cannot bring in any heavy machinery.. We are trying to "design" our hydraulic press (steel frame with ballast) that would be able to press in the sheet piles next to adjacent buildings without any vibrations..It's a long shot but we have an idea, we will see if feasible.. But still for this project with no ground water I would like to go with something "simple", I was thinking about those Titan micropiles but I've never done this before..
RE: Alternative to underpinning
RE: Alternative to underpinning
RE: Alternative to underpinning
RE: Alternative to underpinning
If the building wall load is pretty high, you might be able to install underpinning without needing tieback anchors, soil nails, or internal cross bracing. However, massive underpinning piers (3 to 4 feet thick) will significantly decrease the useable floor space in the basement. Most owners don't want to do this. Soil nails and tiebacks need permanent easements from the adjacent property owners. Titan micropiles or helical piers can vertically support the walls but you still have to address the lateral earth and surcharge loads.
Your best choice is probably to underpin the walls with concrete underpinning piers, brace the top of the underpinning just above or below the new floor slab (near the original bottom of wall or basement slab), then build the new elevated floor slab which can accept the lateral load that the bracing was carrying. Then, remove the bracing. It may be cheaper for the owner to just buy or build another house with a deeper basement. I recently designed underpinning so an owner could increase basement height to 30 feet so he could have an indoor basketball/tennis court in the basement. It was very expensive!
www.PeirceEngineering.com
RE: Alternative to underpinning
Yes another project includes 10' lowering the exist. slab..I realize it is a complicated issue..but there is no neighbors agreement for underpinning anyways so we have to come up with an alternative..
My boss's got an idea for a self-made hydraulic press to push the sheet piles into the ground just next to the adjacent buildings with very little vibration..ballasted steel frame with hydraulic cylinders and custom-made guide..we have a contractor who likes the idea and is willing to invest and fabricate it..so we will see, maybe it will work out:)
RE: Alternative to underpinning
Job 2 - If you need to underpin party walls, I don't believe the adjacent co-owner of the wall can stop you. He may be able to stop you from using tieback anchors under his building. Also, the underpinning may not be allowed to extend beyond the inside face of his basement foundation wall or wall footing. The hydraulic SSP driving system sounds like pie-in-the-sky. It will take up a lot of room when against the party wall. The SSP will be significantly offset from the wall, making the basement much narrower. Also, SSP is usually not stiff enough to prevent movement and settling of the adjacent structure.
See attached PDF.
www.PeirceEngineering.com
RE: Alternative to underpinning
RE: Alternative to underpinning
www.PeirceEngineering.com
RE: Alternative to underpinning
RE: Alternative to underpinning
RE: Alternative to underpinning
www.PeirceEngineering.com
RE: Alternative to underpinning
Rubble walls are junk and unpredictable + you'd be introducing bending + that doesn't completely solve your soe - you'd still need to retain the soil under the neighbors. Don't do it.
You have two options: conventional underpinning or something like a secant wall. The secant wall or similar will be very expensive and they'll lose space. Pay the neighbors more for an agreement or forget it.
Don't mess with rubble walls - I've had a bad experience with them and don't suggest taking any risks. They're just piles of stone.
RE: Alternative to underpinning
RE: Alternative to underpinning