Question

They are there so the sidewalk can expand during hot weather.

Answer 1

Thermal expansion joints in bridges allow for the expansion and contraction of the bridge due to temperature changes.

Step-by-step explanation:

Thermal expansion joints are present in bridges to allow for the expansion and contraction of the bridge due to changes in temperature. When the bridge is exposed to hot weather, it expands, and the expansion joints prevent the bridge from buckling. These expansion joints are designed to accommodate the changes in length caused by thermal expansion and contraction.

For example, the Auckland Harbour Bridge in New Zealand has thermal expansion joints that allow it to change length without buckling.