What are the effects of expansion and contraction in the design of bridges pavements and MRT lines?

- MRT and Railway tracks

if a continuous track of metal is used, it will expand in hot weather and bent. trains running on bent tracks may be derailed. to prevent this, railway tracks are laid in sections with expansion gaps between them. A sliding joint between adjoining rails allows them to expand without bending.

- bridges

both concrete and steel bridges are built with allowance for expansion and contraction due to changes in the surrounding temperatures. Rollers and sliding joints allow for the movements of the bridges as it expands and contracts