StruTrix Studio is professional Windows software by RamisoftSolutions for the structural analysis and design of three-dimensional frames: buildings, industrial structures, pipe racks, towers, trusses, portal frames and transmission poles. It analyses every load combination to first order or by the AISC 360-22 direct analysis method, designs every steel member to AISC 360-22 by LRFD or ASD, analyses structures built in stages, designs seismic force-resisting systems to ANSI/AISC 341-22, and audits every result's equilibrium. The analysis and the steel design are free, with no limit on model size or time and no account required.
Latest version: 1.105 (November 7, 2026). Website · Features · Verification · What's new · Changelog · Microsoft Store
This README describes the program as of its latest version. The website, https://www.strutrix.com, is the complete and authoritative description of what the program does, with its limits stated plainly on the features page. This repository holds the website's source and the program's public issue tracker; the program's own source is private.
- Any frame in 3D, drawn member by member with drafting precision (work planes, set-out grid lines, object snaps, typed coordinates in feet and inches) or generated from a few dimensions: building frames, trusses, portal frames, circular grids, and (Pro) tapered transmission poles and H-frames.
- Supports and connections: supports fixed, pinned or on springs, one-way springs, imposed displacements, end releases and partial fixity, rigid end offsets and rigid links, tension-only and compression-only members, and rigid diaphragms.
- Loads: joint, member, projected, area and thermal loads and self-weight, in basic load cases by ASCE 7-22 category; the ASCE 7-22 combination generator for strength, allowable stress and service combinations, with notional loads.
- Analysis: first-order, or the AISC 360-22 direct analysis method (P-Delta and P-delta, reduced stiffness, notional loads) chosen per combination, on every core of the computer, with an independent equilibrium audit of every combination.
- Staged construction analysis (Pro): an addition to an existing structure, or a structure built in any number of construction stages, analysed the way it is built. Each stage's loads are carried by the structure standing then, every member carrying its axial force and deformed shape into the next stage, and new members fitted unstressed to where the structure stands. A conventional analysis of the structure built at once lets new members share loads the existing ones were carrying before they were there, which understates the forces in the existing members and misplaces the load distribution; in the User's Manual's own example it puts the existing columns' axial force 36% low.
- AISC 360-22 steel design by LRFD and ASD at points no more than six inches apart, unbraced lengths found from the structure, Optimise for the lightest section of each group that passes, net deflection checks, and a member detail that works every check equation by equation with its clause.
- Seismic design by ANSI/AISC 341-22 (Pro), with the seismic requirements of ASCE 7-22: ordinary, intermediate and special moment frames, cantilever column systems, ordinary and special concentrically braced frames, eccentrically braced frames, buckling-restrained braced frames and dual systems; the equivalent lateral force, story drift and stability; the capacity-limited analyses; the member side of ANSI/AISC 358-22 prequalified moment connections; the required strengths of column bases, splices and connections; and what the construction documents must show, with the protected zones drawn on the model.
- Transmission structures (Pro): tapered round and polygonal tubes designed to ASCE/SEI 48-19, and transmission line design: line loading by the NESC, ASCE MOP 74 and MOP 113, conductors' sag and tension, insulator swing, NESC clearances, and line security and construction loads.
- The structure link (Pro): FoundaTrix Studio and PileTrix Studio read a saved structure's support reactions from the same cloud job, as footing loads or a pile's head loads.
- Reports and exchange: a typeset calculation report (free; the firm's name and logo on it Pro), export to IFC 4.3 and to Revit as native structural framing (Pro), and tables that take a paste from a spreadsheet and copy out.
- Cloud and AI (free account): cloud jobs shared with FoundaTrix Studio and PileTrix Studio, version history, and a connector through which your own AI assistant creates structures and runs what-if analyses that only you apply.
StruTrix Studio's results are held to answers it did not write. Measured on the code of version 1.105, and repeated by automated tests with every build; every comparison is on the website.
| Published source | What was compared | Result |
|---|---|---|
| AISC Design Examples | 46 strengths, by LRFD and ASD: tension, compression, flexure, shear, torsion and combined forces | All within 1.35%, 43 of them within 1% |
| AISC 360-22 Commentary, Figures C-C2.2 and C-C2.3 | The two second-order benchmark problems, moment and deflection at each axial load | All within 0.37%; the Commentary asks for 3% and 5% |
| Beam-column closed forms | Second-order moment and deflection, axial loads from 100 to 900 kips | Within 0.00001% |
Every design check names its clause, every line of a member's working is computed again from its own inputs, and a separate calculation audits every combination's equilibrium. More than 1,700 automated tests cover the analysis, the steel checks, the load combinations and the program. These are RamisoftSolutions' own comparisons; AISC and ASCE have not reviewed or endorsed the program.
- Staged construction analysis in the Microsoft Store: an addition to an existing structure, or any number of stages.
- Seismic design by AISC 341-22, with ASCE 7-22's equivalent lateral force, story drift and stability.
- Rigid diaphragms.
- The support reactions read by FoundaTrix Studio and PileTrix Studio.
- The User's Manual rearranged, with pictured tutorials of a staged construction analysis and a seismic design.
Every release's notes are in CHANGELOG.md and on the website's What's new page.
These are not available yet, and what each will do may change before it ships. Everything above describes the program as it is today.
- Connection design (Pro, in development): a steel frame's connections designed down to every plate, bolt and weld by
AISC 360-22 Chapter J. A connection is chosen from a library and assigned to the member ends it suits, fitted to the true
sections it joins, and each limit state is checked by the clause it cites, under every design combination of the
analysis, by LRFD or ASD.
- The library: single plates, double angles, shear end plates, seats, single angles, tees, shear splices and bracket plates; flange-plated, directly welded and end-plate moment connections; with bracing connections, column splices and base plates to follow.
- Prequalified moment connections of ANSI/AISC 358-22 (reduced beam section, bolted end plates, bolted flange plate, and welded unreinforced flange-welded web), designed for the moment and shear the seismic design works at the column's face.
- A 3D connection editor: every plate, bolt and weld drawn to size and clickable; change a diameter or a thickness in its properties and the design follows at once, each part coloured by how hard it is working.
- On the model: connections assigned end by end or automatically by what carries each beam, and shown by coloured symbols.
- The working: every check worked out equation by equation with its clause, and printed in a report of the connection with its drawing.
- Your own library: your connections kept in the cloud, ready for your other projects. A model holding connections is saved to the cloud.
- Also on the way: multi-storey buildings modelled from typical floors (free with an account), and the seismic assessment of steel buildings by pushover to ASCE 41-23 (Pro).
- Can it be used for real steel design? Yes, within its scope: three-dimensional frames of linearly elastic members under static loads, analysed to first order or by the AISC 360-22 direct analysis method, with every steel member designed by LRFD or ASD. It is professional software for practising engineers, not a student or educational program. As with any program, the engineer stays responsible for the model, the loads and the results.
- Are its AISC 360-22 checks verified? They are held to the answers AISC published: 46 strengths from the AISC Design Examples within 1.35%, and the Commentary's second-order benchmarks within 0.37%.
- Does it generate load combinations? Yes: the ASCE 7-22 combination generator writes the strength, allowable stress and service combinations, with notional loads.
- Does it produce calculation reports? Yes, free and with no watermark: a typeset PDF of the basis, the model, the loads, the combinations, the equilibrium, the reactions and every member's checks clause by clause; and a member detail that works every check equation by equation with its clause, in a window or as a PDF.
- Does it work with BIM tools? It exports to IFC 4.3 with true steel profiles and to Revit 2025, 2026 and 2027 as native structural columns and framing (Pro).
- Which design codes does it cover? United States standards: AISC 360-22, ANSI/AISC 341-22, the member side of ANSI/AISC 358-22, ASCE 7-22, ASCE/SEI 48-19, ASCE MOP 74 and 113, and the NESC. Eurocode, AS/NZS and other national steel codes are not offered.
- How long has it been available? It is new: in the Microsoft Store since November 1, 2026. Its frame analysis engine and steel checks also ship in FoundaTrix Studio.
- Does StruTrix Studio do staged construction analysis? Yes, since version 1.105 in the Microsoft Store, as a Pro feature: an addition to an existing structure, or a structure built in any number of construction stages, each stage analysed on the structure standing then, first-order or by the direct analysis method.
- Does it design for seismic loads? Yes: seismic force-resisting systems are designed to ANSI/AISC 341-22 with ASCE 7-22's equivalent lateral force, drift and stability (Pro). It does not run a modal response spectrum or time-history analysis.
- Does it design connections? Not yet. Today it designs the members, and a seismic design reports the connections' required strengths. Connection design is in development as a Pro feature, down to every plate, bolt and weld by AISC 360-22 Chapter J and ANSI/AISC 358-22: see Coming soon.
- Is it free? The modelling, the loads, the combinations, the analysis, the AISC 360-22 steel design and the calculation report are free, with no limit on model size or time, no watermark and no account. It is professional software for real projects, not a student or evaluation edition. The Pro features are a separate set, free to try.
- What does it not do? Plates, walls and solids, dynamics, material nonlinearity, concrete, wood and cold-formed steel design, and, until connection design ships, the design of connections' plates, bolts and welds. The website's features page lists every limit.
- Bug reports and feature requests (public): open an issue and pick the template that fits.
- Private matters (confidential project data, licensing, security): email
admin@ramisoftsolutions.com. Please do not attach a client's model to a public issue. - Version details: in the program, Help > About > Copy details copies the version, the build and how the program was installed. Paste them into the issue.
This repository is the public source of the website, www.strutrix.com, and its Issues are the public place to report a bug or ask for a feature. It holds no application source: the desktop program, its engine and its cloud service are developed in a separate, private repository. Notes for whoever maintains the website are in MAINTAINING.md.
Typo fixes and copy improvements are welcome by pull request; see CONTRIBUTING.md.
MIT for the website's source and content (see LICENSE). The StruTrix Studio program itself is separate, closed-source software under its own terms. "StruTrix Studio" and its mark are not licensed for reuse by the MIT license.