Free public beta · Windows desktop
Lateral pile analysis, done to a plan-check standard.
Coupled axial + lateral response for drilled piers and caissons in layered soil — a Naik-Peyrot p-y solver, ACI 318-25 Mander-confined section design, and independent geotechnical and global-equilibrium audits, in one desktop tool.
Windows 10/11 (64-bit) · no account required to try it · auto-updates via ClickOnce
Built by a practicing engineer
Designed and maintained by an engineer who runs it on real transmission, refinery, and drilled-shaft foundation work — not a classroom exercise.
Built for real geometries
Exercised against messy multi-layer soil profiles and governing load combinations from live projects, not idealized textbook cases.
Built for the plan check
Designed from day one to produce numbers you can defend to a plan checker, not just a rough back-of-envelope estimate.
What it does
Six checks, one converged solution.
Every load case is solved once and screened from every angle — structural, geotechnical, and numerical.
Coupled axial + lateral solver
A finite-difference Naik-Peyrot p-y solver with Newton-Raphson iteration and Armijo line search, coupled to an axial load-transfer solve for every load case.
ACI 318-25 section design
A Mander-confined fiber section drives a full P-M interaction and shear check against ACI 318-25, per node, per load case.
Soil-side mobilization checks
Lateral p-y springs, shaft skin friction, and tip bearing are each screened against their ultimate capacity — independent of the structural demand-capacity ratio.
Global equilibrium verification
Every converged solution is re-integrated and checked for force and moment closure — catching sign errors or discretization bugs a converged residual alone can't reveal.
Groundwater & effective stress
An optional water-table model automatically derives buoyant unit weights and effective stress, so submerged sites don't require manual bookkeeping.
Service & LRFD load routing
Run every combination in one pass — structural checks route to strength cases and soil/deflection checks route to service cases automatically, then the governing case is reported for each.
Under the hood
Technical specifications.
The methods, references, and data workflows behind every run — so you can verify the tool's reasoning, not just trust it.
Layered p-y solver
- Coupled axial + lateral formulation, Naik & Peyrot1
- Finite-difference discretization, banded LU factorization (LAPACK DGBSV-style — O(n), not O(n³))
- Uniform or Graded (non-uniform) meshing — element spacing auto-sized to the head condition, refined near the surface where curvature is sharpest
- Newton-Raphson iteration with Armijo backtracking line search for robust convergence
- Outer variable-EI loop updates section stiffness from the Mander moment-curvature response each pass
8.5 s → 15–25 ms warm
A typical multi-case analysis, after a pass dedicated entirely to solver throughput — same solver, same results, just faster.
- Every enabled load combination solves concurrently, each to its own convergence
- Each worker gets an independently cloned pile and solver workspace — no shared mutable state
- Degree of parallelism is user-configurable; a serial mode is available for step-through debugging
- Unlimited load combinations per project
Eight built-in p-y criteria
- Soft clay — Matlock2
- Stiff clay below the water table — Reese, Cox & Koop3
- Stiff clay above the water table (dry) — Welch & Reese4
- Sand — Reese, Cox & Koop5, full piecewise curve for the most accurate near-ultimate behavior
- API sand (offshore) — API RP 2A-WSD6
- Weak rock — Reese7
- Strong rock (vuggy limestone) — FHWA-NHI-10-01611
- Linear elastic (user-defined modulus)
- Georgiadis8 equivalent-depth correction applied across layered profiles
- Optional groundwater / effective-stress overlay — automatic buoyant unit weights below the water table
FHWA-NHI-10-016 skin friction & end bearing
- Clay, sand, and rock skin-friction and end-bearing formulas aligned to FHWA-NHI-10-01611
- N60-based sand capacity — enter SPT blow count per layer for beta-method skin friction and a correlated end-bearing capacity
- Per-layer rock side-resistance method — Normal, degraded/caving socket, or Colorado DOT claystone, chosen per layer
- Per-geomaterial ASD/LRFD resistance factors — distinct values by soil type and by compression vs. uplift, with a one-click FHWA preset
- Solved from the same coupled axial + lateral run — no separate hand calc to reconcile
ACI 318-25 section check
- Mander-confined fiber section, per ACI CODE-318-2510
- Full P-M interaction diagram and shear check, per node, per load case
- Confinement model per Mander, Priestley & Park9 drives the variable-EI feedback loop
- Reinforcement input by bar count/size or by target steel ratio (ρg%) — your choice
Independent verification audit
- A separate post-solve check re-integrates every converged solution — it does not reuse solver internals, so a sign or discretization bug can't hide from it
- Confirms lateral force balance, lateral moment balance (including the P-Delta secondary moment), and axial force balance
- Flags physical-sanity issues: numerical blow-up, deflection exceeding the pile diameter, or degenerate section stiffness
Service & LRFD routing
- Service (unfactored) vs. LRFD/strength combinations are tagged per case
- Section checks route to strength cases; soil-mobilization and deflection checks route to service cases — automatically
- Per-case dead-load factor keeps self-weight consistent with the combination (e.g. 0.9D for an uplift check)
Import, export, and reporting
- Native JSON project files (
.lpcj) - Excel-compatible copy/paste for soil layers and load cases — bulk-edit in Excel, paste straight back in, no file conversion needed
- Right-click any chart to copy it as an image or copy its underlying data Excel-ready — standardized across every plot in the app
- A full numbered governing-design report, ready to paste into a submittal
Optional, never required
- Local
.lpcjfiles are the default — the tool works fully offline, forever, without an account - Sign in once (optional) to save projects to the cloud and pick them up on another machine
- Nothing about the free tier depends on signing in
- Naik, T.R. & Peyrot, A.H. (1976). "Analysis and Design of Laterally Loaded Piles and Caissons in a Layered Soil System," ASCE National Structural Engineering Conference.
- Matlock, H. (1970). "Correlations for design of laterally loaded piles in soft clay," 2nd Offshore Technology Conference, Paper 1204.
- Reese, L.C., Cox, W.R. & Koop, F.D. (1975). "Field testing and analysis of laterally loaded piles in stiff clay," 7th OTC, Paper 2312.
- Welch, R.C. & Reese, L.C. (1972). "Laterally Loaded Behavior of Drilled Shafts," Research Report 89-10, Center for Highway Research, University of Texas at Austin.
- Reese, L.C., Cox, W.R. & Koop, F.D. (1974). "Analysis of laterally loaded piles in sand," 6th OTC, Paper 2080.
- API (2010). RP 2A-WSD, Recommended Practice for Planning, Designing and Constructing Fixed Offshore Platforms, 22nd Ed., American Petroleum Institute.
- Reese, L.C. (1997). "Analysis of laterally loaded piles in weak rock," J. Geotech. & Geoenv. Engrg., ASCE, 123(11), pp. 1010-1017.
- Georgiadis, M. (1983). "Development of p-y curves for layered soils," Proc. Geotech. Practice in Offshore Engineering, ASCE.
- Mander, J.B., Priestley, M.J.N. & Park, R. (1988). "Theoretical stress-strain model for confined concrete," J. Struct. Engrg., ASCE, 114(8), pp. 1804-1826.
- ACI Committee 318 (2025). ACI CODE-318-25 Building Code Requirements for Structural Concrete and Commentary, American Concrete Institute.
- FHWA (2010). Drilled Shafts: Construction Procedures and LRFD Design Methods, FHWA-NHI-10-016 (Brown, Turner & Castelli).
See it in action
From load case to governing check.
A sample of the plots and checks generated for every run.
Illustrative previews below — real product screenshots are coming as the site fills in.
Shear & moment diagrams
Full-length V(z) and M(z) profiles for every load case, plotted alongside the deflected shape.
Per-section DCR checking
Every node's demand point is plotted against the P-M envelope — green, amber, or red at a glance.
P-Delta analysis
Head-to-tip offset under axial load is tracked as a depth-varying secondary moment, not a single scalar fudge factor.
Soil layer modeling
A to-scale, color-coded strata sketch with a live water-table overlay — the same profile the solver sees.
Pro preview · free to try
An AI assistant that's grounded in your actual project.
Not a generic chatbot bolted on the side — it reads your live pile/soil setup, your results, and your pushover output, and answers from them.
Grounded in your project
Reads your live pile, soil, and section setup, the governing case, DCRs, soil-mobilization ratios, and pushover output directly — it doesn't guess at numbers it can't point to.
Fact-checked, not just fluent
Every number in a reply is checked against the tool output it actually came from. Anything it can't trace back to your project is flagged, not silently trusted.
Answers you can verify
Methodology and "how do I…" questions are answered by searching the same User's Manual you can open yourself — so you can check the source, not just take its word for it.
A real chat, not a form
A native desktop chat window that streams replies token-by-token with live Markdown formatting and status updates while it works — open it alongside the main window, not instead of it.
Grounded in published literature
Search the actual papers your analysis methods are built on — Naik & Peyrot, Matlock, Reese, Mander, and more — and click straight through to the cited page of the source.
Finds projects across your whole cloud library
Ask it to pull up every project within a radius of a site, filter by pile diameter or other properties, or search your Scope-of-Work text by meaning, not just keyword — all from the same chat window.
Your data stays yours.
The assistant answers only from your own project — never from anyone else's data. Anything sent to run it is treated as confidential and used solely to power that session. We never share, sell, or use it to train models without your explicit consent.
Pricing
Free for practicing engineers. Forever.
Not a trial. Not a countdown. The current version of RPile is free to download, free to run, and free to keep — for good.
Try it. Break it. Smoke-test it.
Run your next real project through it — a messy multi-layer profile, an awkward load combination, whatever you'd normally reach for a p-y solver to handle. The more practicing engineers push it against real geometries, the faster it gets better for everyone. Found something it gets wrong? That's exactly what Report a Bug is for.
Download Free BetaLimited-time preview
Free stays free. Pro is free to try — for now.
Sign in and every current Pro-track feature unlocks automatically, free, for a limited time. When Pro ships as a paid tier, everything in Free today stays free — forever.
Free
Everything a practicing engineer needs to run and defend a lateral pile analysis. No account required.
- Coupled axial + lateral solver
- ACI 318-25 section design
- Soil-mobilization & equilibrium checks
- Groundwater / effective-stress modeling
- Unlimited projects, load cases, and re-runs
- Client & multi-pile-analysis projects — every pile at a site, in one place
- Per-pile coordinates on a live map — pick OpenStreetMap or Esri imagery
- Public soil-model library — browse models shared by other engineers, sorted by distance to your site
- Cloud project version history — every save is a recoverable version
- Recycle bin for deleted cloud projects
Pro Preview
Sign in and every current Pro-track feature is unlocked automatically — free, while the preview lasts.
- Pushover (capacity-curve) analysis — ultimate lateral capacity, ductility, and structural-vs-soil failure mode, per load case
- Branded PDF reports with your firm's logo
- Custom, user-defined p-y soil curves
- AI assistant — grounded Q&A over your live project, results, and pushover output
- Reference document search — ground the AI assistant in the actual published papers behind the methods, with clickable citations
- Interactive map view — browse your cloud projects and soil-model library by location
- Site-boundary attachments — a shapefile, KML/KMZ, or one you sketch by hand, right on the map
- AI-powered cloud project search — radius, property, and semantic search, right from the chat
- Organizations — shared team projects across your firm, with checkout locking
Pro
Once the preview ends, Pro becomes a paid tier for teams and firms — pricing and timeline still TBD. Already built and in active testing:
- Seismic deep-foundation detailing — jurisdiction-aware reinforcement requirements, AI-researched from official sources and engineer-confirmed
- Parametric study — automated sensitivity sweeps to find the optimal pile geometry
- Probabilistic / Monte Carlo analysis — fragility curves and reliability statistics
- AI-assisted what-if investigations — the assistant proposes a fix and solver-verifies it before telling you
Before you install
System requirements
RPile ships as a signed ClickOnce install with automatic updates.
RPile is in active public beta
It is an engineering aid, not a substitute for engineering judgment. Independently verify all outputs against your project's applicable codes and your own checks before relying on them in a stamped submittal.
Feedback loop
Found a bug? Have an idea?
Two channels are open — pick whichever fits your issue.
GitHub Issues
Search whether it's already reported, file a bug or feature request with the templates
provided, and track the fix. Best for most reports — attach a sanitized .lpcj
file if you can.
For confidential project data, plan-check questions, or licensing inquiries. The in-app Help > Report a Bug command pre-fills this with your case number and project file attached.
Send an Email