What is the role of bearings in bridge performance, and what signs indicate bearing distress?

• A. Bearings are decorative; there are no distress signs.
• B. Bearings accommodate movement and transfer loads; signs include misalignment, cracking, excessive play, leakage.
• C. Bearings do not affect performance.
• D. Bearings only support vertical loads.

Answer: (B)

Bearings in bridges are designed to allow movement while transferring loads from the deck to the supports. They accommodate thermal expansion and contraction, rotations, and some horizontal movement caused by traffic, wind, or seismic activity, all while passing vertical loads and moderating horizontal forces through their type and geometry. When a bearing starts to distress, you’ll see signs such as misalignment of the bearing seating, cracking in bearing components or in surrounding concrete/steel, excessive play or looseness that indicates reduced stiffness, and leakage of lubricant or hydraulic fluid from pot or other fluid-filled bearings. Deterioration of elastomeric pads, corrosion, or visible deformation, settling, or lifting of the bearing, plus unusual movement under load, also point to problems. The other statements miss the essential function of bearings: they’re not decorative, they do affect performance, and they don’t just support vertical loads—they enable movement and distribute forces to protect the structure.