What occurs during uniform settlement specifically?

The correct answer focuses on the nature of uniform settlement, which involves vertical movement across the entire structure. Uniform settlement occurs when the foundation of a structure sinks evenly, meaning that all parts of the structure lower at the same rate. This type of movement does not create tilting or rotation; instead, it results in a straight downward shift. The integrity of the structure remains intact as its original shape is preserved, even though it may be positioned lower in relation to the ground.

Uniform settlement contrasts with other types of movement that may occur in structures, such as lateral movement, which involves shifting sideways, or rotational changes, which can occur during uneven loading or localized failures. Uneven loading affects specific supports rather than causing a uniform, whole-structure shift. Understanding the implications of uniform settlement is crucial for assessing the safety and stability of bridges and other in-service structures.