Pile movement immediately after detensioning tieback

[jdonville]

Is there any literature on the movement of piles when the ties are released/detensioned? I've been asked to comment on this, but it's the first time anybody has asked. My initial Google has not turned up any obvious results...Any help appreciated.

J

 

[PEinc]

I am not aware of any literature. However, I would think that the deflection after detensioning the tiebacks would depend on the quality of the backfill in front of the soldier beams or sheets.

http://www.PeirceEngineering.com

 

[ishvaaag]

In my view, and for a properly designed foundation, such movement should be kept by design to serviceable levels, for the practice is to detension when the basement floors are built and then able to take the inwards forces.

The structural scheme must be valid both under the original tie system and the new, bridging between the new support at basement floor levels. Since these use to be quite close, the span for the inwards push is small and so feasible to sustain high push with reasonable basement walls.

So for construction as described movement should be minimal, and designed to be so.

 

[wmta]

the deflection will depend on the new existing structure and the procedure for removal

 

[InDepth]

What are you trying to accomplish by detensioning? Are you detensioning after a retaining or basement wall has been built, or are you detensioning after improper tie installation, or are you detensioning because excavation of the soil on the tie side is being performed (poor coordination)?