Civil Engineering Professional Engineer Practice Exam

What type of bridge is known as the longest among various types?

1. Beam bridge

2. Arch bridge

3. Suspension bridge

4. Truss bridge

The correct answer is: Suspension bridge

The suspension bridge is recognized as the longest type among various bridge designs primarily due to its structural configuration. This type of bridge uses cables that are hung from tall towers and are capable of spanning greater distances than other bridge designs. The design allows for the weight of the deck to be distributed efficiently through the cables, resulting in minimal need for support structures below. This feature makes suspension bridges ideal for crossing wide bodies of water or deep valleys, where traditional methods of support would be impractical or too expensive. Notable examples include the Golden Gate Bridge and the Brooklyn Bridge, showcasing their capability to span impressive lengths that are hard to achieve with beam, arch, or truss bridges. In contrast, beam bridges typically have a more limited span, constrained by the bending moments and shear forces acting on horizontal beams. Arch bridges, while span-efficient under compression, still do not match the long spans achievable by suspension designs. Truss bridges, though effective for medium spans, are also limited compared to suspension bridges in terms of maximum length.