Dear ADONIS,
My question is about the pretens load of the tiebacks.

In a simple three-stage example: 1) excavate, 2) install tieback and set pretens, 3) excavate again.
The question is that the load that results in the tieback, after running stage 2, turns out to be less than that specified in the data.

I imagine this to be the case, because the model establishes the prestress load, then lets it deform and there the prestress is partially lost.

But in a practical case, one establishes the prestressing load and operates on the structure until the specified value is achieved, so the axial load in the tieback after running stage 2 should be the one declared in the data.

Am I correct? Am I doing something wrong? Should I enter the data differently?

I attach the ajs file for your better illustration

I send you the best regard

Aldo

yes your observation is correct. there are multiple solutions for this issue. the simplest one is to keep increasing the initial pretension force until the specified value is achieved after equilibrium then you continue with the rest of stages.

I didn't do that in the tutorial to keep it simple.