Which bridge type is one of the oldest with semicircular arch?

• A. Arch Bridge
• B. Suspension Bridge
• C. Cantilever Bridge
• D. Cable-Stayed Bridge

Answer: (A)

The essential idea is how arches carry loads. An arch turns vertical forces into compressive stresses that flow along the curved path into the supports, and a semicircular shape is a simple, effective way to realize that action. This geometry promotes uniform compression through the stone blocks (voussoirs) toward the keystone and into strong abutments, making the structure stable even with basic masonry. Because stone masonry was the earliest workable material and the arch action doesn’t rely on tension, builders in ancient times naturally used semicircular arches, which is why arch bridges are among the oldest forms to employ this shape. In contrast, suspension, cantilever, and cable-stayed designs depend on tensioned elements and more advanced construction techniques, and they arose later as materials and methods advanced.