What part of the bridge permits longitudinal expansion and contraction?

What part of the bridge permits longitudinal expansion and contraction?

• A. Bearing
• B. Pavement
• C. Deck
• D. Abutment

Answer: (A)

Longitudinal expansion and contraction happen as temperature changes make the span grow or shrink, and the bearing is what allows that movement while still transferring loads to the supports. Bearings are designed to slide or roll in the longitudinal direction, so the deck can move a bit back and forth without causing bending or cracking. The deck and pavement carry the load, but they don’t accommodate the movement themselves; the bearing provides the controlled space for that movement. Abutments anchor the ends and guide movement, but the actual allowance for length change comes from the bearing.

Longitudinal expansion and contraction happen as temperature changes make the span grow or shrink, and the bearing is what allows that movement while still transferring loads to the supports. Bearings are designed to slide or roll in the longitudinal direction, so the deck can move a bit back and forth without causing bending or cracking. The deck and pavement carry the load, but they don’t accommodate the movement themselves; the bearing provides the controlled space for that movement. Abutments anchor the ends and guide movement, but the actual allowance for length change comes from the bearing.