Which type of settlement can cause significant distress in a bridge?

Differential settlement can cause significant distress in a bridge because it refers to the uneven settling of different parts of a structure or its foundation. When one section of a bridge settles more than another, it can create stresses in the bridge components due to misalignment, which may lead to major structural issues such as cracking, tilting, or even failure of the bridge over time. This unevenness affects the equilibrium of the entire structure and can compromise the safety and integrity of the bridge, necessitating repairs or reinstatement of the alignment.

In contrast, uniform settlement involves the entire bridge settling evenly, which typically does not introduce as much distress since all parts of the structure move together without differential movement. Lateral settlement, which refers to movement along the horizontal plane, may also affect stability but is less commonly recognized as a critical type of settlement in bridge structures. Simultaneous settlement implies uniform action across the foundation; hence, it does not create the localized stresses seen with differential settlement. Therefore, differential settlement is the primary concern for bridge inspectors looking to identify and mitigate potential structural failures.