Free Linear Structural Analysis
Run first-order static analysis on any structure — beams, trusses, frames, and full 3D models. Get bending moments, shear forces, axial loads, deflections, and support reactions instantly using the Direct Stiffness Method. No signup or download required.
Run analysis and view moment, shear, axial, and deflection results instantly
What is Linear Structural Analysis?
Linear (first-order) analysis solves for forces and displacements assuming small deformations and linear elastic material behaviour. It's the foundation of structural engineering — sufficient for the vast majority of design situations and required by all major design codes as the baseline analysis method.
AutoCalcs uses the Direct Stiffness Method — the same finite element approach used by professional software like SAP2000, ETABS, and SpaceGass. Every member is modelled with 12 degrees of freedom (6 per node), capturing axial, shear, bending, and torsional behaviour simultaneously.
Structure Types
- Beams (simply supported, cantilever, continuous)
- Trusses (pin-jointed)
- Frames (portal, multi-storey, braced)
- Full 3D structures
Load Types
- Point loads and moments
- Distributed loads (uniform, triangular)
- Self-weight
- Multiple load cases and combinations
Results
- Bending moment diagrams (My, Mz)
- Shear force diagrams (Vy, Vz)
- Axial force and torsion diagrams
- Deflected shape and support reactions
Features
- Real steel, timber, and concrete section libraries
- Steel design code checks (Pro)
- Upgrade to P-Delta when needed
- Save, share, and export projects
When is Linear Analysis Sufficient?
Linear analysis is appropriate when deformations are small relative to the structure's dimensions — which covers most buildings, bridges, and industrial structures. Design codes like AISC 360, Eurocode 3, AS 4100, and CSA S16 all permit first-order analysis provided stability effects are handled through amplification factors or effective length methods.
For structures where second-order effects are significant (tall buildings, slender columns, high axial loads), AutoCalcs also offers P-Delta analysis — just toggle the analysis type and re-run.
Why Choose AutoCalcs?
- Professional-Grade Solver — Same Direct Stiffness Method used by SAP2000, ETABS, and SpaceGass.
- Full 3D Capability — Not limited to 2D. Model structures in any orientation with loads in any direction.
- Design Code Checks — Integrated AISC 360, Eurocode 3, AS 4100, and CSA S16 steel design checks (Pro).
- Instant Access — No installation, no signup. Open your browser and start modelling.
- Open Source Engine — Powered by verified open-source FEA libraries.