In the context of beam behavior, which term refers to the bending effect caused by a transverse load on a bridge member?

• A. Shear
• B. Moment
• C. Axial force
• D. Torsion

Answer: (B)

Bending moment is the internal turning effect that results when a beam is subjected to a transverse load. When a force acts perpendicular to the beam, it tends to bend the member, and the beam develops an internal moment that resists that bend. This moment is what causes curvature, with the top fibers typically in compression and the bottom fibers in tension.

Compare with the other ideas: shear is the internal force that resists sliding between cross-sections, axial force is along the length of the beam, and torsion is twisting from a torque. The bending moment specifically describes the bending effect produced by the transverse load.