Structural Arch, Rib & Bridge Load Calculator
Calculate horizontal thrust, rib compressive load, and bending moment conversion for arches and spans.
Input Parameters
Calculation Results
Formula & How Structural Arch, Rib & Bridge Load Calculator Works
Arches are exceptionally strong because their curved parabolic geometry converts vertical bending loads into lateral compressive thrust. A straight beam experiences heavy destructive bending tension, whereas an arch channels forces directly into the abutments.
- Enter Clear Span Length (meters): Input your target parameter value.
- Enter Total Distributed Load (kN): Input your target parameter value.
- Enter Arch Rise at Crown (meters): Input your target parameter value.
- Enter Number of Structural Ribs / Arches: Input your target parameter value.
- Apply Formula: Calculate using
Horizontal Thrust H = (W × L) / (8 × h) | Resultant R = √(H² + V²). - Review Results: View exact computed answers, metrics, and worked mathematical proofs.
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Frequently Asked Questions (FAQs)
Why can an arch bridge hold much more weight than a flat beam?
An arch resolves vertical loads into pure compression along the curve of the arch ring, eliminating the severe tension stresses that cause flat beams to sag and crack.
What happens if the arch rise is too shallow?
A shallow arch (small rise h) dramatically increases the horizontal outward thrust against the abutments (H ∝ 1/h), requiring massive foundation buttresses.
Authoritative Standards & Verified Reference Citations
Calculations and mathematical logic on this page are grounded in published statutory rules, regulatory standards, and official government data published by the following bodies:
Australian Standards including AS/NZS 3000 (Wiring Rules), AS 3600 (Concrete Structures), and AS 4100 (Steel Structures).
Accreditation and technical guidelines for civil, structural, mechanical, and electrical engineering.
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