Free · No account · Release 0.0.1
StructArk is a free engineering notebook for structural engineers. Mathcad automates calculations and reports. StructArk also automates the FEM analysis, the drawings and the BIM model, all from the same inputs. Write it once, run it on every job, and share it.
One design
Calculation, analysis, model and drawings aren't four tools, and none of them is the main one. They're four faces of the same structural design: why it stands, how it behaves, what it is, and how to build it. Today each lives in its own program, and you keep them agreeing by hand. In StructArk they're one design: change any number, and all four follow.
The calculation
MEd = w L2 / 8 = 45 kN m
As ≤ Aprov
209.0 ≤ 226 mm2 OK
The analysis
The model
The drawings
One design, always agrees.
What it does
Change a span or a bar diameter and the notebook re-solves and re-draws. Every picture is a document that ships with the app, as the app draws it.
An input is a line with its value, its unit and its limits, and the sheet turns it into a form with a slider. A formula is a line too, and the sheet writes it out the way a checking engineer reads it: the symbols, the numbers put in, and the result with its unit. A table holds fixed values, and a formula reads the row the form picks. A form or a table saves as CSV, which Excel opens.
Nodes, members, meshes, supports and loads are one line each. The model is solved in three dimensions, its diagrams and contours are drawn on the sheet, and every result is a value the formulas below it can check.
A detail is drawn in real units on layers, with its hatches, dimensions and notes, from the same values as the calculation. It stands on the sheet, and Export DXF saves it for any CAD program.
Levels, grids and elements are written with the values of the calculation, so the model follows the form. It is drawn in 3D on the sheet, opens as large as the window, and IFC saves it for any BIM program. Its quantities come back as values.
A curve is a formula over a range, drawn with its axes, units and legend. What the figure shows is published as a value: its largest value, a root, an area, or the point where two curves cross.
One line turns a document right to left. The text and the sheet run from the right, and formulas, numbers and units still read from the left, as they do on paper.
Excel
Mathcad · Blockpad · CalcpadCE
One plain-text document
Report
What the sheet shows is what prints: numbered headings, the inputs as a table, the calculation line by line, and every check with its verdict. The browser's own print makes the PDF, and a 3D view prints as a picture of it.
Mistakes
What is wrong and on which line, in one sentence. The same words stand under the line, in the list and on the sheet. A name whose line has a mistake has no value, so nothing below it is computed from an old number.
Verification
The analysis engine is tested against textbook results. Each row is one of its tests, run on every change, with the tolerance the test holds it to.
| Benchmark | Reference | Agreement |
|---|---|---|
| Axial bar, end load: extension | PL / EA | Exact |
| Cantilever, tip load: deflection | PL³ / 3EI | Exact |
| Cantilever, tip load: base reactions | P and PL | Exact |
| Simple beam, uniform load: midspan deflection | 5wL⁴ / 384EI | Exact |
| Fixed beam, uniform load: end and midspan moments | wL² / 12 and wL² / 24 | Exact |
| 3D frame: joint displacements and rotations | Logan, A First Course in the Finite Element Method, example 5.8 | Within 2 % |
| Cantilever column, second order (P-Delta): sway | The exact solution, with tan kL | Within 4 % |
| Simply supported square plate, uniform pressure: centre deflection | Timoshenko, Theory of Plates and Shells, table 8 | Within 5 % |
| Simply supported square plate, uniform pressure: centre moment | Timoshenko, Theory of Plates and Shells, table 8 | Within 10 % |
| Ring plate held at its outer edge: deflection at the hole | The plate equation, solved in closed form | Within 2 % |
Exact: equal to the closed form to the 8th decimal place or better.
The other engines are held the same way. Every row of the language reference is a test of the calculation engine: what each word computes, and the formula the sheet draws for it. Every drawing test reads its DXF file back, every building-model test reads its IFC file back with an independent reader, and every document that ships with the app is computed in the tests.
Planned
If you want to be told when each is ready, join the waitlist.
One email when each tool is ready. Your address is used for nothing else.
Turns a hand sketch and a hand calculation into a document, for you to check and sign.
Keeps your notebooks in your account and opens them on any machine.
Engineers publish libraries of elements for their own country's code, and sell them to other engineers.
The notebook is free and needs no account. It opens with a finished example: move an input, and watch the calculation, the analysis and the drawing follow.
