Expansion joints


Bridges and sidewalks:

•    Bridges and sidewalks are built in sections.

•    There are spaces between the sections called expansion joints.

•    Expansion joints allow steel and concrete to expand without cracking.

•    The expansion joints narrow when bridge segments expand in hot weather.


Expansion joints:

•    Expansion joints in a bridge separate when the side-by-side segments of a bridge contract in cold weather.


•    Railway tracks consist of two parallel metal rails joined together.

•    Small gaps, called expansion gaps, are deliberately left between the rails as there is an expansion of the rails in hot weather.

•    If we hold a very hot glass tumbler under cold water, it cracks.

•    This is because the outer surface of the glass comes in direct contact with cold water and contracts more as compared to the inner surface.