Step 1
Model the pile in your bridge model
Global modeling allows modeling of the super/sub structure and foundation in the same model.
From LPile Springs to Response Spectrum Without Leaving MIDAS
Civil NX builds LPile-style p-y springs directly from your borelogs - it's included in your Civil NX license.
Date
Sep 16, 2026Wednesday
Time
1:00 – 2:00 PM EST10:00 – 11:00 AM PST
Credit
1 PDHLive attendance required
Session Overview
Response spectrum analysis can't run with nonlinear springs. So you run it, read the displacements, update every spring by hand, and run it again - several rounds to converge one case, repeated for every load case.
Civil NX now runs that loop for you. You set a tolerance, click run, and it recalculates secant stiffness from the p-y curve until the change falls inside it.
In this hour we build p-y springs from borelogs, run the iterative response spectrum analysis live, and check the converged stiffness against a hand iteration, step for step.
Already in Civil NX. No add-on module, no separate license.
Soil data to spring, in three steps
From the pile you're already modeling to a spring you can run any analysis on.
Step 1
Step 2
Turn soil layers into P-Y curves
Borelog data becomes a P-Y curve for every node → nonlinear p-y springs, generated automatically, without a separate LPile step.
Step 3
Get a spring ready to assign
Each curve becomes a force-deformation function you can use in any analysis.
Response Spectrum Analysis
The same springs update their secant stiffness automatically, iteration by iteration, until they land inside your tolerance.
Learning Objectives
By the end of the hour you'll be able to set up and defend an automatically converged response spectrum analysis in your own model.
- Read the code requirement correctlySeparate what AASHTO LRFD Seismic actually mandates from what state seismic guidelines prescribe about secant stiffness in RSA.
- Build p-y springs in the bridge modelDefine nonlinear soil springs from borelog data without exporting the substructure to a separate geotechnical program.
- Set a tolerance and let it convergeConfigure the equivalent linearization loop so secant stiffness updates itself each iteration instead of by hand.
- Verify the converged answerUse the iteration history to show a reviewer that the automated result matches a manual check, step for step.
Key Features
Civil NX processes point springs, extracts displacement results, and updates stiffness iteratively until convergence - then hands you the full history to compare.
Soil data to spring automatically
Point springs are read and processed directly from the model, so nothing has to be exported, edited, and imported back.
Iterative stiffness updates
Stiffness values update iteratively until they converge on your tolerance. You start the run once instead of restarting it five times.
Displacement results extraction
Displacements come straight out of the analysis and drive the next stiffness value - no copying numbers between windows.
Stiffness evolution tracking
Track how each spring's stiffness moved across iterations. That trace is what you hand a reviewer asking how the value was reached.
Presented By
Dev Bhararia
Structural Engineer, MIDAS
Dev holds a Master's degree in Structural Engineering from SVNIT Surat and brings valuable experience from working on a wide range of bridge and building projects. His background includes both design and on-site execution, giving him a well-rounded perspective of structural systems. Dev is particularly enthusiastic about addressing complex engineering challenges and enhancing structural safety and efficiency.
Event Agenda
50 minutes of presentation and live demo, then 10 minutes of open Q&A. Times are in EST.
- 1:00 – 1:05 PM 5 min Why this became manual workThe gap between what the code asks for and what an RSA solver can do with nonlinear springs.
- 1:05 – 1:50 PM 45 min Code basis, live demo, and verificationAASHTO LRFD Seismic and state guidelines, the iterative response spectrum workflow in Civil NX, and converged results checked against a hand iteration.
- 1:50 – 2:00 PM 10 min Live Q&ABring your model conditions. Questions submitted during registration go first.
Save Your Seat
Learn how Civil NX builds nonlinear p-y soil springs and runs iterative response spectrum analysis automatically.
