Can Staad Pro v8i do a push-over analysis of a frame that includes multi-linear spring supports?
The structure in question is a pier or wharf that is supported on vertical piles. The lateral load is entirely resisted by the piles. During push-over, plastic hinges form at the top of the piles and in the piles some distance below ground surface.
My ideas is that the pile members in STAAD would be assigned user-defined hinges, and the piles would have multi-linear spring supports to model the adjacent soil.
The FEMA 356 backbone moment-rotation curve for hinges should be fine for this; the input parameters for the hinges would be developed with other software (not STAAD, which apparently can't do moment-curvature analysis of sections).
Sorry, No.