Which bridge is a single-construction type, sometimes shaped like a 'K', commonly used for overpasses and providing greater vertical clearance?

• A. Truss Bridge
• B. Rigid Frame Bridge
• C. Movable Bridge
• D. Cantilever Bridge

Answer: (B)

A rigid frame bridge is built as one continuous, monolithic structure where the deck and supporting columns are rigidly connected and act together as a single unit. This tight, uninterrupted framework lets the bridge carry bending moments across the supports without hinged joints, making construction efficient and enabling a relatively shallow profile. That direct, rigid connection is especially advantageous for overpasses, where you want maximum vertical clearance below the deck and minimal obstruction from joints or separate girder systems. In skewed alignments, the frame can take on a configuration that looks like a 'K' from certain perspectives, which helps fit the crossing geometry while maintaining structural stiffness.

Truss bridges involve many interconnected members with joints, so they aren’t a single-construction unit. Movable bridges are designed to shift position to allow traffic or water flow, not as a fixed single unit. Cantilever bridges are built from two extending arms that meet in the middle, which is not a single continuous frame.