ICyBolts is an interactive bolt group analysis application for structural engineers built with React, TypeScript, Vite, and Three.js. The software solves for the Instantaneous Center of Rotation (IC) of eccentrically loaded bolt groups using the Brandt Method published in AISC design references.
The tool is intended for rapid visualization and evaluation of:
- AISC bolt group coefficient checks
- Bolt bearing design
- Slip-critical bolt checks
- Eccentrically loaded bolt groups
- Instantaneous center equilibrium analysis
- Bolt demand / capacity ratios (DCR)
- Interactive structural connection review
The application combines a modern dark-themed engineering UI with a live Three.js viewport for rapid structural analysis and visualization.
ICyBolts is available online at:
ICyBolts implements the Brandt Method for instantaneous center analysis of bolt groups:
Rapid Determination of Ultimate Strength of Eccentrically Loaded Bolt Groups
G. Donald Brandt
The solver iteratively determines the location of the instantaneous center of rotation and distributes bolt forces based on nonlinear deformation relationships described in the AISC methodology.
The software is particularly well suited for:
- AISC eccentric bolt group checks
- Bolt coefficient ("C") calculations
- Bearing bolt capacity evaluation
- Slip-critical bolt evaluation
- Structural steel connection design workflows
- Instantaneous center of rotation solver
- Brandt method implementation
- Nonlinear bolt force distribution
- Bolt force vector visualization
- Real-time DCR evaluation
- Bolt group coefficient (C) calculations
- AISC bearing bolt capacities
- ASD and LRFD support
- Bolt grade selection
- Single and double shear checks
- Slip coefficient (μ) support
- Faying surface selection
- Standard and short-slot hole support
- ASD and LRFD capacities
- Slip-critical resistance checks
The project uses:
- React Three Fiber
- Three.js
- Drei
to provide:
- Interactive bolt visualization
- Force vector rendering
- Instantaneous center visualization
- Selection tools
- Dynamic bolt highlighting
- Live analysis feedback
- Save project to JSON
- Import project from JSON
- Print analysis results to PDF
- Parametric bolt grid generation
- Interactive bolt selection
- Multi-select editing
- Drag window selection
- Ctrl-click selection support
- Point load input
- Magnitude and angle control
- Applied force visualization
- Bolt coefficient output
- Maximum bolt DCR
- Capacity checks
- Force equilibrium review
- Instantaneous center display
- Bolt-by-bolt force results
- React
- TypeScript
- Vite
- Three.js
- React Three Fiber
- Drei
src/
├── analysis/
│ ├── analyzeBoltGroup.ts
│ └── brandt.ts
│
├── components/
│ ├── BoltPanel.tsx
│ ├── LoadPanel.tsx
│ ├── AppliedLoadArrow.tsx
│ ├── BoltSelectionBox.tsx
│ ├── BottomDock.tsx
│ └── FilePanel.tsx
│
├── data/
│ └── boltSizes.ts
│
├── types/
│ ├── bolts.ts
│ └── app.ts
│
├── App.tsx
└── main.tsx
- Define bolt geometry
- Create applied loads
- Run instantaneous center analysis
- Review bolt force vectors
- Review bolt coefficient and DCR
- Print engineering summary to PDF
Planned future enhancements include:
- Eurocode bolt design support
- Metric bolt capacity libraries
- AISC Steel Construction Manual
- AISC Design Guide Resources
- Brandt, G. Donald
Rapid Determination of Ultimate Strength of Eccentrically Loaded Bolt Groups
The screenshot below shows ICyBolts solving an eccentrically loaded slip-critical bolt group with instantaneous center visualization and live force vectors.
MIT License
Copyright (c) 2026 Austin Guter, Retug LLC
Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
Austin Guter
Retug LLC