Question

Why are the girders supporting bridges mounted on rollers?

Answer 1

1. Bridges are mounted on the rollers so that they can expand in summer and contract in winter.
2. Therefore to avoid any damage to the bridge, rollers are used.
3. One end of the girders is fixed into the concrete or brick pillars and its other end is not fixed but is placed on rollers.
4. The reason is that if there is any rise in the temperature of the atmosphere, the girder can freely expand without affecting the pillars.