Thanh Tu Do

Structural engineering & software

Software for structural engineers.

Engineering software and technical writing from real structural practice — tools you can run, derivations you can follow.

Explore projectsRead the writing
  • Structural engineeringDesigning real buildings: high-rise and long-span systems.
  • Engineering softwareBuilding automation and analysis tools for that work.
  • Technical writingPublishing derivations worked through in full, not summarised.
A rendered study model of a tapering high-rise tower on a display plinth.
var displacements = etabs.Model
    .AnalysisResults
    .GetJointDispl("", eItemTypeElm.Objects);
Typed joint displacements.From the ETABSharp case study

Recent project

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C#.NETETABS APIMCPNuGet

ETABSharp

A strongly typed C# wrapper over the ETABS COM API, and an MCP server on the same surface: an AI assistant can read a model, build one, and run the analysis.

  • A thin wrapper, not a replacement: methods map onto the ETABS API rather than hiding it.
  • Typed records instead of ref arrays, and exceptions instead of ret != 0 checks.
  • An MCP server on the same typed surface: query results, add sections, run design checks.
  • The core wrapper is stable and in production use. The MCP layer is still in active development.
Source on GitHubAPI documentation

“What’s the maximum story drift in load case EQ-X? Is it within the 0.5% limit?”

Asked in plain English through the MCP server. Read the article

Latest writing

All writing
Jul 31, 202614 min

Measured, Not Guessed: How This Site Was Built

Static Astro, Svelte islands that have to justify themselves, and quality gates that read the built output rather than the source. Why the architecture is shaped that way, and what it caught the site claiming about itself.

structuralApr 15, 202618 min

The Stiffness Matrix from First Principles

devApr 8, 202611 min

Talking to ETABS in Natural Language: ETABSharp + MCP

devMar 20, 202615 min

Saola: A Grasshopper Plugin Built on ETABSharp

Tools & resources

All tools

Beam Calculator

Shear, moment and deflection diagrams for common beam configurations, computed in the browser over unit-tested engineering modules.

  • Simply supported, cantilever and fixed cases, with point or distributed load.
  • Results and diagrams update as you type, with no login and no backend.

ACI Quick Reference

ACI 318-14 concrete properties, ASTM standard reinforcing bar dimensions, and per-foot area spacing tables. Also in the browser, also with nothing to install.