NASCLA Accredited Commercial General ContractorSite WorkMedium
A construction site requires the installation of a temporary bridge to allow heavy equipment to cross a small stream without disturbing the streambed. To minimize environmental impact and ensure stability, what is the most appropriate type of temporary bridge for this application?
- APre-fabricated modular bridge (e.g., Bailey bridge)
- BCulvert installation with fill
- CCauseway of compacted gravel
- DTimber plank bridge directly on stream bed
Show answer & explanationAnswer & explanation
Correct answer: A. Pre-fabricated modular bridge (e.g., Bailey bridge)
Pre-fabricated modular bridges, such as Bailey bridges, are designed for rapid assembly and deployment. They span the entire stream without requiring supports in the streambed, minimizing environmental disturbance, and are robust enough for heavy equipment. This aligns perfectly with the goal of minimizing environmental impact and ensuring stability.
Why the other options are wrong
- B. Culvert installation with fill would permanently alter the streambed and is not a temporary bridge solution.
- C. A causeway of compacted gravel would involve significant fill in the streambed, causing major environmental impact.
- D. Timber planks directly on the streambed would disturb the stream and likely not be stable for heavy equipment.
Temporary Modular Bridges
Bridges constructed from standardized, interchangeable components, designed for quick assembly and disassembly. They are often used for temporary access over obstacles like streams or ravines, minimizing environmental impact.
- Pre-fabricated components.
- Rapid assembly and disassembly.
- Spans obstacles without in-stream supports.
- Minimizes environmental disturbance.
Memory trick: For streams, choose a bridge that floats, not one that digs and bloats.