Question

Why is there a gap at the joints of rails and of cement concrete bridges?

Answer 1

metals expand when they are heated and in summer season due to high temperature it expands

Answer 2

Answer:

Concrete and steel expand with increasing temperatures and contracts as temperature drops. To put it simply, the expansion gap allows the members to alternately expand and contract without deforming to the point where it damages the structure

Concrete is not an elastic substance, and therefore it does not bend or stretch without failure.

That gap is referred to as an expansion gap. Concrete and steel expand with increasing temperatures and contracts as temperature drops.

To put it simply, the expansion gap allows the members to alternately expand and contract without deforming to the point where it damages the structure or itself.