Why do engineers love bridges? They're outstanding in their field.
Why do engineers love bridges? They're outstanding in their field.
Iconic bridges with a deck hung from cables draped over tall towers, capable of spanning enormous distances.
Total in US
96
Poor Condition
20.8%
Avg Sufficiency
50.8
Average Age
87 yrs
Suspension bridges are among the most recognizable and elegant structures in the world. They use a system of cables hung from tall towers to support the bridge deck far below, allowing them to span distances that would be impossible for most other bridge types. The main cables drape in a characteristic parabolic curve between the towers and are anchored firmly into the ground or massive concrete blocks at each end.
The design has been refined over centuries, evolving from simple rope bridges used by ancient civilizations to the massive steel-cable structures we see today. Modern suspension bridges routinely span over a mile, connecting communities across wide rivers, deep valleys, and ocean straits. Their graceful profiles have made many of them beloved landmarks.
Suspension bridges carry some of the heaviest traffic loads in the world and are engineered to flex with wind and seismic forces rather than resist them rigidly, making them remarkably resilient in extreme conditions.
The fundamental engineering principle behind a suspension bridge is tension. Two massive main cables are strung over the tops of tall towers and anchored at each end in heavy anchorages. Vertical suspender cables (or hangers) drop from the main cables to support the bridge deck at regular intervals. The weight of the deck and any traffic on it is transferred through the suspender cables to the main cables, which carry the load in tension to the towers. The towers, in turn, transmit the compressive forces down to the foundations. The anchorages at each end resist the enormous horizontal pull of the main cables, often requiring foundations drilled deep into bedrock or enormous gravity anchorages. This elegant distribution of forces allows suspension bridges to span much greater distances than beam or arch bridges.
The main cables of the Golden Gate Bridge contain 80,000 miles of wire, enough to circle the Earth more than three times. Each cable is made of 27,572 individual wires bundled together.
Golden Gate Bridge (San Francisco, CA)
Brooklyn Bridge (New York, NY)
Verrazano-Narrows Bridge (New York, NY)
Mackinac Bridge (Michigan)
George Washington Bridge (New York/New Jersey)
Akashi Kaikyo Bridge (Japan, world's longest at 1,991m span)
| Rank | State | Count | % of Type |
|---|---|---|---|
| 1 | New York | 20 | 20.8% |
| 2 | California | 13 | 13.5% |
| 3 | Pennsylvania | 11 | 11.5% |
| 4 | New Jersey | 7 | 7.3% |
| 5 |
There are 96 suspension bridges in the United States.
Modern bridges where cables run directly from towers to the deck, creating a dramatic fan or harp pattern.
One of the oldest bridge forms, using a curved structure to transfer loads outward to abutments at each end.
Bridges built from interconnected triangular elements, combining strength and material efficiency.
The most common bridge type in America, using horizontal beams supported by piers to carry the deck.
| 5 |
| 5.2% |
| 6 | Texas | 4 | 4.2% |
| 7 | Ohio | 4 | 4.2% |
| 8 | Missouri | 3 | 3.1% |
| 9 | Oregon | 3 | 3.1% |
| 10 | Illinois | 2 | 2.1% |