A bridge expansion joint is a crucial component in bridge construction that allows for the natural movement of the bridge structure. As temperatures change, materials like concrete and steel expand and contract. The expansion joint accommodates these movements, preventing damage to the bridge and ensuring safety for vehicles and pedestrians. These joints are typically made from flexible materials such as rubber or metal and are designed to absorb stress caused by temperature fluctuations, traffic loads, and seismic activity. Proper installation and maintenance of bridge expansion joints are essential for the longevity and integrity of the bridge structure.