I am currently running a response spectrum analysis on a bridge model built on drilled shaft. The way I modeled the piles, is divided into 5' frames and assigned a line spring to each one. I had already calculated the PY and imported it into CSI Bridge.
However I have two identical piles and only the left one is rotating tremendously by about 940 rad/in. I cannot figure why. I checked restraints, the PY values but the Left pile acting in unstable way.
Any advise will be greatly appreciated.