Permanent Sheet Pile or Underpin?

[Ben29]

I am writing a proposal for the design of a new 3-story commercial building with basement. The new building will be constructed on a vacant lot between (2) existing buildings. Building #1 is a large brick "house" circa 1920 that is currently used for commercial purposes. Building #3 is an end-of-unit brick rowhouse circa 1920.

The new building will have a very deep basement as shown in sketch below. How can this be constructed? Can I just specify that this will be a delegated design of a permanent sheet-pile wall? Is that the best course of action?

The dimensions shown in the image below are approximate.

The second image below is something I found online. I am not very well-versed in sheet piling applications.

I don't think you can just 'underpin' the sidewall of Building #3 without also underpinning the front and rear wall with a stepped footing.

 

[GeorgeTheCivilEngineer]

Think I'd be going for a secant CFA pile wall.

This is fairly specialised work so depending on the stage of the project, aim for plenty of space for the permanent structure and the temporary works, such as whalers supporting the piles not interfering with the construction of the permanent basement.

 

[HTURKAK]

I am afraid these old buildings may develop cracks moreover may collapse during sheet pile driving due to vibrations .
I will suggest underpinning for the bldg no 3 and slope retention for the the bldg no 1.
You may check your local market for the jet grout subcontractors.
Pls look to the following doc. to get insight.
...



He is like a man building a house, who dug deep and laid the foundation on the rock. And when the flood arose, the stream beat vehemently against that house, and could not shake it, for it was founded on the rock..

Luke 6:48

 

[phamENG]

I'm with HTURKAK.

No way you don't damage the adjacent building and the whole block besides if you try to drive it even vibrate sheet piles in.

Also, those sheets would have to be several feet away from the existing for clearance to drive them, losing space in the basement and forcing you to cantilever your building on that side.

Underpinning all the way.

 

[Mark_J]

Build a 5' retaining wall for Building number 1, in sections.
Underpin Building #3, 3 times, in sections. Each section below is wider than above.
If you are in the Philadelphia area, feel free to reach out. I work with a contractor who is excellent in this kind of work.