Driving sheet piles by existing building.

[PBEIT]

I have an addition going next to an existing building. I need to put a wall with a strip footing approx. 4' below an existing spread footing. The size of the spread footing is unknown but its edge distance to the new walls strip footing edge would be anywhere from 1.5-3.5 feet. The building houses mechanical equipment and is a steel frame metal building. I need to know how close I can get to a structure like this without damaging or disturbing the soils too much. I don't know if you could hammer these piles in this close or if pressing them in at this distance is an option. Sorry, I don't have any information on the soils. If you have any advice please tell me if its a rule of thumb or the code/book you got it from.

Thank you.

 

[oldestguy]

I wouldn't try to comment until a detailed soil situation is known.

This is a place where an experienced geotech engineer is consulted. There may be options than sheet piles.

 

[PEinc]

It sounds to me like you need underpinning, not SSP.

http://www.PeirceEngineering.com

 

[Ron]

Agree with OG....this needs some geotech input.

Driving sheet piling next to an existing structure is fraught with issues. You need to do a before and after, detailed condition assessment of the existing structure. If cracks are found in the "before", they need to be marked to see if they expand during piling placement. Document everything with good photos and video. Check everything....walls, windows, sealants, floor slabs, roof, sidewalks, driveways, etc.

Next you need to monitor the vibrations created during the pile placement. Makes no difference whether driven or vibrated in....need to monitor both. If hydraulically pushed, then monitoring is not necessary as long as the equipment alone doesn't create a lot of vibration.

You might consider a slurry wall or similar instead of sheet piling.

 

[PEinc]

Sheeting is usually a flexible system. Not good for supporting structures if flexible. Deflection = settlement.
Driving SSP could damage the building and disrupt operations inside. Vibrations + settlement = damage.
Pressing SSP is probably not an option due to the size of the project, to the closeness of the existing building, and to the cost and unavailability of the pressing equipment.
As oldestguy said, you need soil and ground water info and also info on the existing foundations.

http://www.PeirceEngineering.com