Grades 6–8 · Systems
How do a cable-stayed bridge’s straight cables help hold up its road?
On a cable-stayed bridge, many angled cables connect the road deck directly to one or more towers. These cables are stretched in tension. Their upward pull helps support the weight of the deck and its traffic.
In the diagramAngled stays carry deck loads to a towerblue: cable pull on deckorange: weighttower → foundation → ground
Because each cable is angled, its tension has both vertical and horizontal effects. The deck and the rest of the cable arrangement must resist and balance those effects. A cable cannot simply push upward like a rigid column.
Loads pass through the towers and other supports toward the foundations and ground. The deck also distributes loads between its cable connections. The visible fan of cables is therefore part of an interacting structure.
This arrangement differs from a suspension bridge, where smaller hangers connect the deck to a main draped cable. Both designs use tension, but their load routes are organized differently. Seeing where each cable ends helps explain how the whole bridge can remain in balance.
About this explanation
Starting knowledge: Distinguish tension from compression and recognize that forces must ultimately reach foundations and ground.
Sources
- Federal Highway Administration — Introduction to Mechanics of Inclined Cables