A bridge featuring a floor supported at or near the bottom while its top chords remain unbraced is designated as________________?
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Answer: C. half through type
Explanation
A half through bridge features a floor supported near the bottom chords of the truss. The top chords remain unbraced transversely across the upper portion of the structural frame. This geometric configuration provides adequate clearance for traffic while maintaining overall structural stability. Bridge classifications depend on the vertical position of the roadway relative to the main trusses. Top chords in half through bridges require special stiffening to resist lateral buckling without overhead bracing. This design style balances aesthetic clearance requirements with structural load-carrying efficiency.
Engineers select half through bridges when overhead clearance is strictly limited by surrounding infrastructure. These structures are common in urban railway systems and medium-span highway river crossings. Proper analysis of unbraced top chords is essential to prevent premature compression failure. Deck type bridges carry traffic directly on top of the primary structural support framework. Through type bridges enclose the traffic completely with heavy overhead cross-bracing and top chords. Double deck type bridges support separate traffic tiers on both upper and lower structural levels.
- Subject
- Engineering
- Category
- Civil Engineering
- Topic
- —
- Difficulty
- medium
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