Civil Engineering Professional Engineer Practice Exam

Which load distribution characteristic is associated with truss bridges?

1. All load must be concentrated at the ends

2. Each member can either be in compression or tension

3. They cannot handle large spans

4. They rely on a solid material only

The correct answer is: Each member can either be in compression or tension

The characteristic that describes truss bridges is that each member can either be in compression or tension. In truss bridge design, the structure is composed of interconnected elements, usually arranged in triangular shapes, which helps distribute loads effectively. When a load is applied to the bridge, some members will experience tension, trying to pull apart, while others will experience compression, pushing together. This efficient use of materials allows for lighter structures capable of supporting significant loads. This fundamental behavior of truss members enables these bridges to manage forces effectively, making them ideal for spanning larger distances. In contrast, other options do not accurately reflect the nature of truss bridges. For example, the notion that all load must be concentrated at the ends does not consider the load distribution through the truss, while the claim that trusses cannot handle large spans overlooks their proven performance in various engineering applications. Finally, the idea that trusses rely on solid materials only ignores the innovations in design and materials that allow for flexibility in construction methods and materials used.