According to the position of bridge floor relative to the formation level and the highest flood discharge level, the bridges are classified as
- AFixed-span or movable bridges
- BDeck, through or semi-through bridgesCorrect
- CSimple, continuous or cantilever bridges
- DRiveted, welded or pin-connected bridges
Solution
Concept
Classification of bridges based on bridge floor position
Formula
NONE
Step-by-step solution
1. Review the criterion in the question: position of the bridge floor relative to the formation level and highest flood discharge level. 2. In bridge engineering, this criterion classifies bridges into deck bridges, through bridges, and semi-through bridges. 3. Deck bridges have roadways on the top chord/flange, through bridges have roadways at the bottom chord, and semi-through have an intermediate floor without top lateral bracing. 4. Therefore, option B is the correct classification. Answer: B
Explanation
According to the position of the bridge floor relative to the superstructure, bridges are classified as deck, through, or semi-through bridges. In a deck bridge, the floor is at or near the top of the main girders/trusses. In a through bridge, the floor is at or near the bottom with overhead lateral bracing. In a semi-through bridge, the floor is at an intermediate level.
Why the other options are wrong
A) Fixed-span or movable classifies bridges according to mobility for navigation. C) Simple, continuous or cantilever classifies bridges according to the structural system/support arrangement. D) Riveted, welded or pin-connected classifies bridges according to structural joint connections.
Shortcut
Floor position = Deck (top), Through (bottom), Semi-through (intermediate).
Common mistake
Confusing bridge classification by floor position with classification by structural mechanism (cantilever/continuous) or mobility (movable/fixed).
Correct answer: B) Deck, through or semi-through bridges