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Strut-and-Tie Model Design, verified.

AStrutTie designs the concrete members where ordinary beam theory doesn't apply — deep beams, corbels, pier caps, footings, frame corners — with a strut-and-tie model you can see, check, and hand to a reviewer.

Run AStrutTie in your browserFree · Google sign-in · up to 15 nodesSee plans & pricingFree forever · Standard · Pro · Perpetual
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  • Strut — concrete compression
  • Tie — reinforcement tension
  • Nodal zone
A strut-and-tie model of a deep beam: compression struts (dashed), a tension tie (solid), and nodal zones where they meet.
  • ✓ 29 automated gate suites · 2348 checks green How we verify →
  • ✓ Cross-verified against independent references — published ACI 318-19 hand calculations, SAP2000, and a from-scratch numpy oracle
  • ✓ Your AI know-how data stays yours — never used to train models for other customers Data policy →

Model selection, not strength checks

The essence of STM is the selection of the truss model that best represents the load path, yet that selection is not uniquely determined — it must satisfy equilibrium, ductility, serviceability and buildability at once, and the struts and ties must not deviate far from the elastic stress trajectories.

AStrutTie therefore provides guidance for selecting a truss model that follows the load path, based on the stress flow, and automatically re-performs the strength checks when the geometry or loads are changed.

Try it live

When the load is changed, member forces and required section areas update in real time.

Run live

See the product

Real screens from AStrutTie v2, in the order you work: build the model, compare it to the stress flow, check it against the code, hand in the report.

AStrutTie template galleryAStrutTie template gallery
16 D-region templatesDeep beams, corbels, pile caps, pier copings, anchorage zones — a verified strut-tie model in minutes.
AStrutTie 3D strut-and-tie modelAStrutTie 3D strut-and-tie model
3D strut-and-tie3D pile caps and pier / abutment grids — the model, the checks and the report in three dimensions.
AStrutTie stress-flow underlay behind the strut-tie modelAStrutTie stress-flow underlay behind the strut-tie model
Check against the stress flowCompare your model to the real stress field (built-in plane-stress FEM) — the hard part of STM, guided.
AStrutTie required and maximum section bands on the strut-tie modelAStrutTie required and maximum section bands on the strut-tie model
Checks you can seeRequired vs maximum section area drawn right on the model — the safety margin, visible per member.
AStrutTie Design Review strength-check tablesAStrutTie Design Review strength-check tables
Code checks, in the openEvery strut, tie and nodal zone against the design code — pass / fail and safety factor, per member.
AStrutTie calculation report outputAStrutTie calculation report output
A submittable reportA full calculation report — geometry, member forces and code checks — ready to hand in.

What it does

The full strut-and-tie model design workflow, from geometry to a submittable report.

16 D-region templates

Footings (spread, pile, abutment, 3D pile cap, pier/abutment grids), deep beams, continuous deep beams, corbels, pier copings, frame corner, anchor plate, PSC anchorage, box girder, lattice girder — a verified strut-tie model in minutes, not hours.

5 design codes

KDS (strength design & limit state), ACI 318, AASHTO LRFD, and Eurocode 2 — strut, tie, and nodal-zone checks with the correct nominal strength for each code.

Truss + plane-solid solvers

Determinate and indeterminate truss analysis, plane-stress FE, principal stress flow, and ESO topology guidance for the model shape.

Reports reviewers accept

Full HTML calculation reports — open in Word or print to PDF — with every check traceable to the code clause.

DXF import

Bring member outlines and truss geometry straight from CAD instead of re-drawing them.

One workspace, web and desktop

The new AStrutTie is one codebase for browser and desktop: a single workspace, a command palette, and one-click auto-fix for failing checks.

AI review assistance — rolling out

A senior-engineer-style reading of the computed results — governing members, NG checks, next steps — in plain language. Every number remains the verified solver's; the AI never recomputes. The judgement and the signature remain the engineer's. Model suggestions are in development.

Rebuilt, not repackaged

AStrutTie has been rebuilt from the ground up: the same verified strength equations, in a modern engine that operates in the browser without installation, and on the desktop from the same code.

  • NG one-click auto-fix — envelope and increase-only, never silently unsafe
  • Command palette (Ctrl+K) and keyboard-first workflow
  • Analysis and design checks run locally via WebAssembly — your model stays in the browser

Ready to verify your strut-and-tie model design?

Run AStrutTie in your browserView pricing