The short answer: A typical medium-sized bridge weighs roughly 1,000 to 10,000 tons (about 900 to 9,000 metric tonnes), though weight varies enormously with size and design.
Bridge weight by type
Bridges range from small footbridges to massive suspension spans, and their weight depends heavily on length, width, and the materials used.
| Type (example) | Typical weight |
|---|---|
| Small pedestrian footbridge | a few tons to dozens of tons |
| Short highway overpass | hundreds to a few thousand tons |
| Medium-sized road bridge | about 1,000 to 10,000 tons |
| Large steel suspension bridge | tens of thousands of tons or more |
What affects bridge weight
- Span length. Longer bridges require far more material and weigh much more.
- Materials. Steel, concrete, and wood have very different weights for the same structure.
- Bridge type. Suspension, arch, beam, and cable-stayed designs vary widely in weight.
- Deck width. More traffic lanes mean a wider, heavier deck.
- Load requirements. Bridges built for heavy vehicles need stronger, heavier components.
How bridge weight compares
A medium-sized bridge at several thousand tons can weigh as much as a thousand or more cars combined, while major suspension bridges rival the weight of a small skyscraper.
Frequently asked questions
What is the heaviest part of a bridge?
The deck and main supporting structure, such as the towers and cables on a suspension bridge or the beams on a beam bridge, usually account for most of the weight. Foundations buried underground can also be very heavy.
Do steel or concrete bridges weigh more?
For the same span, concrete bridges generally weigh more than steel ones because concrete is denser and used in larger volumes. Steel allows lighter, longer spans but requires careful engineering.
How is a bridge's weight calculated?
Engineers calculate a bridge's weight by summing the volume of each material and multiplying by its density. This is part of the dead-load analysis used to design safe foundations and supports.
