allowable deflection in soldier pile ret. walls 1

[cheklipot]

what is the allowable deflection in a hp-soldier pile retaining wall.

as per the IDOT standards, the deflection shoulw be less than 1"? is this a MUST?

any suggestions as to what is an accepectable limit for deflection?
i have used the software ALLPILE to determine the deflection, based on multiple soil layers. i did find a bug it in;-)
any other softwares?

 

[GeoPaveTraffic]

The amount of allowable deflection should be based on what is being protected by the wall. If the item/area being protected can withstand 5 inches of movement, and the piles are not overstressed, then 5 inches reduced by an appropriate safety factor would be the allowable deflection for design.

As for software, I have always used a spreadsheet for analizing walls.

 

[DRC1]

I agree with GeoPave, Allowable movement depends a lot on what is being protected. Other considerations are internal stresses in the steel, which can be checked by normal analysis methods. Another consideration is the support method- is it canalevered, braced or tied back ? you can get a lot of movement at the top with a cantilever, some with a brace, includinng "settling in" of components that are not accounted for in normal deflection comps and very little at the tie back. Quality of instalation will also play a role.
Another thing to consider is how do you compute deflection. Pressure envlopes are an approximation, and the point of pile fixity is often somewhat arbitrary. We can relatively easily compute capacities of wall systems, but deflection predictions are more of an estimate.
If you are putting out specs for design build wall systems, The reviewer should be able to see the estimate of wall deflection. Rather than limit the deflection to an arbitrary criteria, I would suggest making deflection calculations and the designer's comments on the effect of the deflection a required part of the submittal.

Good Luck

 

[cheklipot]

thanks \for the feedback!
my bad, i had given incomplete information.

i have proposed a soldier pile retaining wall for a channel section. the retaned ht is approx. 10-12 ft.
when sat. soil condition is considered behind the ret. wall.. the deflectin is abt 4" which is unaccepectable.
in some sections \the soil behind the wall is sand or silt...under these conditions hydrostatic pr behind the wall is not an issue...and then the deflection is around 1.2".

so my question was pertaining to what is an accepectable deflection limit?
the bending stress in the H piles is not an issue.(it is well within the limit).

thanks again for the replies.

 

[DRC1]

To answer our question directly, I do not know of any code requirements for sheeting deflection. If your project specications have limits you must address those. Otherwise it is a matter of judgement. For a 10 ft wall, 4" gives you an l/30 which seems high to me. You will notice the deflection and pick up p-delta effects also the deflection ill increase as the excavation proceedes, which may cause minor problems with the lagging. I would try to keep the deflection to around an inch. I would loook at changing site drainage, decreasing soldier pile spacing or excavating aportion of the retained material.
As for programs, "Allpile" is a pile program from Civilsoft. They also make "Shoring" which computes loads and deflections for earth retention systems and would be more suited to your situation. Another program is SPW 911 from Pile Buck. This program is also designed specifically for earth retention

 

[DRC1]

To answer your question directly, I do not know of any code requirements for sheeting deflection. If your project specications have limits you must address those. Otherwise it is a matter of judgement. For a 10 ft wall, 4" gives you an l/30 which seems high to me. You will notice the deflection and pick up p-delta effects also the deflection ill increase as the excavation proceedes, which may cause minor problems with the lagging. I would try to keep the deflection to around an inch. I would loook at changing site drainage, decreasing soldier pile spacing or excavating aportion of the retained material.
As for programs, "Allpile" is a pile program from Civilsoft. They also make "Shoring" which computes loads and deflections for earth retention systems and would be more suited to your situation. Another program is SPW 911 from Pile Buck. This program is also designed specifically for earth retention