Question

why is one end of the beams of steel bridge kept on a roller instead of fixing a pillar
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Answer 1

Answer:

Explanation:

when we have rollers at end then it is allowed to expand freely without any thermal stress. in summer the bridges may expand due to the increase in the temperature and in winters the bridges may compressed due to decrease in the temperature. the rollers helps to increase/decrease the length of the bridge without any thermal stress