The bridge type in which the deck is located in the middle of the main structure.

• A. Through Bridge
• B. Half-Through Bridge
• C. Straight Bridges
• D. Highway Bridge

Answer: (B)

In this concept, bridges are grouped by where the deck sits inside the main supporting frame. A half-through bridge places the deck right through the middle portion of the main structure, with the supporting elements extending both above and below the deck. That mid-height position is what defines it as “half-through.” It’s different from a through bridge, where the deck sits inside a frame that the traffic effectively passes through, with the structure surrounding the deck on both sides. The other two options don’t specify the deck’s position within the main frame or are based on usage rather than geometry, so they don’t match the description.