Springs V Pinned Restraints
Springs V Pinned Restraints
(OP)
Hi All,
Just a general query in respect of springs used to model piles for a raft slab. For initial results I tend to use pinned restraints to model piles simply to get an idea of what the likely pile loads will be; but once detailed site investigation information and/or a pile design information is available I sometimes recheck using spring coefficients very simply taken as the ultimate pile capacity divided by the calculated settlement. This can produce quite stiff spring coefficients but when compared with reactions resulting from pinned restraints are as expected lower, since the pinned restraints will be infinitely stiff for the translation directions.
My question is how stiff do spring coefficients need to be before they start returning values similar to pinned restraints, if at all?
Regards
Hannis (UK)
Just a general query in respect of springs used to model piles for a raft slab. For initial results I tend to use pinned restraints to model piles simply to get an idea of what the likely pile loads will be; but once detailed site investigation information and/or a pile design information is available I sometimes recheck using spring coefficients very simply taken as the ultimate pile capacity divided by the calculated settlement. This can produce quite stiff spring coefficients but when compared with reactions resulting from pinned restraints are as expected lower, since the pinned restraints will be infinitely stiff for the translation directions.
My question is how stiff do spring coefficients need to be before they start returning values similar to pinned restraints, if at all?
Regards
Hannis (UK)





RE: Springs V Pinned Restraints
As an aside I use similar method to you to design pile loads. Just make sure your conservative on the spring stiffness, (stiffer). Pin supports give hughly conservative results and no load share between piles.
RE: Springs V Pinned Restraints
RE: Springs V Pinned Restraints