Slope Deflection Calculator

A web app for structural engineers to analyse beams and frames with the slope-deflection method — computing fixed-end moments, member end moments, bending-moment and shear-force diagrams, and support reactions, all in the browser.

A powerful tool for structural engineers to calculate beam deflections and moments using the slope deflection method.

Features

• Beam analysis — define spans, supports (fixed, pinned, roller, free), and loads (UDL and point loads), with support settlement (sinking supports) and per-span moment of inertia.
• Frame analysis — analyse rigid plane frames, including sway.
• Automatic generation of the slope-deflection equations and solution of the simultaneous joint-equilibrium (boundary-condition) equations.
• Final member end moments, bending-moment and shear-force (BMSF) diagrams, and support reactions.
• Identification of critical BMSF values along each span.
• Interactive charts and diagrams, with light/dark theme.

Tech stack

• Next.js 14 (App Router) · React 18 · TypeScript
• Tailwind CSS · shadcn/ui (Radix UI)
• Framer Motion (animation) · next-themes (dark mode)
• Chart.js / Recharts (diagrams)

Getting started

The application lives in the duale_sdc-main/ folder.

cd duale_sdc-main
npm install
npm run dev

Open http://localhost:3000 in your browser.

Build for production:

npm run build
npm start

How it works

The slope-deflection method writes each member's end moments in terms of the unknown joint rotations (and sway), combining the member's fixed-end moments with terms in 2EI/L. Enforcing moment equilibrium at every joint produces a system of simultaneous equations; solving it yields the rotations, which are back-substituted into the slope-deflection equations to give the final member end moments. From those, the app derives the bending-moment and shear-force diagrams and the support reactions.

Project structure

duale_sdc-main/
├── app/
│   ├── page.tsx        # Landing page (Beams / Frames)
│   ├── beams/          # Beam analysis UI
│   ├── frames/         # Frame analysis UI
│   ├── components/     # Forms, charts, diagrams
│   └── utils/          # Slope-deflection, FEM, BMSF, reactions logic
├── components/ui/      # shadcn/ui primitives
└── ...

Deployment

Configured for Vercel — vercel.json sets duale_sdc-main as the build target.

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Built by Abdullahi (Olamilekan) Abdulwasiu.