What is the primary function of the open expansion joint in bridge design?

The primary function of the open expansion joint in bridge design is to provide a gap for thermal expansion. Bridges are subject to temperature changes, which cause materials to expand and contract. If these movements are not accommodated, stress can build up, potentially leading to structural damage. Expansion joints, such as open expansion joints, are specifically designed to manage this movement by allowing for the necessary space. This ensures that the bridge can withstand thermal variations without compromising its integrity.

Open expansion joints also serve to facilitate drainage, but their main role centers around accommodating thermal expansion and contraction. By enabling this movement, open expansion joints play a crucial role in maintaining the safety and longevity of bridge structures.