So I was curious as to how others design their piping foundations. I deal a lot with EZ Line supports and we use a third party firm for our foundation designs, but the way we do this is we run our Caesar analysis and provided expected support loads to the third party and they design around that.

But lately we've been butting heads within our group on the best way to model the supports for realistic, yet conservative, loads. One of our guys has determined that a typical EZ Line support has a stiffness of 2E5 lb/in and so he will use that and the prescribed gap when modeling. I have been dealing with our foundation design firm and I start with rigid supports and am provided foundation stiffnesses from them based on soil conditions and loads. This seems to work rather well, but I started to consider using bi-linear restraints instead. This would be to incorporate the steel stiffness of the support and the stiffness of the foundation. Obviously there is quite a bit of difference between the two, and so using a bi-linear should provide a fairly accurate representation of movement and restraint.

I wanted to know how other go about designing their supports and/or foundations. Does anyone disagree with my methods?