What defines the strength of an arch bridge?

The strength of an arch bridge is fundamentally defined by its ability to distribute loads throughout the structure. The arch shape helps transfer the weight of loads from the roadway to the supports at either end, allowing the bridge to carry heavy loads effectively. This load distribution is primarily a result of the geometry of the arch, which channels the forces along its curve and into the abutments, minimizing tension and maximizing compression.

While the material used in construction is certainly important for the overall durability and performance of the bridge, it is the arch's design and its load distribution properties that are key to its strength. The height of the arch and the type of foundation also play roles in the bridge's overall stability and effectiveness, but they are not the primary defining factors of the strength specifically. The arch's ability to handle and distribute stress is what allows it to span significant distances and carry substantial loads without failing.