Civil Engineering Professional Engineer Practice Exam

What is a characteristic requirement for arch bridges in certain terrain?

1. They must be lightweight

2. They often need to be massive

3. They can be made of any material

4. They should be as high as possible

The correct answer is: They often need to be massive

In certain terrain, arch bridges often need to be massive due to the fundamental principles of their design and the types of loads they are engineered to support. Arch bridges rely on the strength of their curved shape to efficiently transfer loads from the bridge deck to the supports at either end. This requires substantial material to create the necessary compressive strength to withstand both live loads and environmental forces like wind or seismic activity. In challenging terrains, such as those with steep slopes or unstable ground conditions, a massive structure can provide the required rigidity and stability to resist deformation and failure. The size and weight of the arch help ensure that it remains anchored and properly supported, enabling it to distribute forces effectively across its span without undue stress on any single part of the structure.