What movement results from unsymmetrical settlement due to horizontal earth pressure?

Unsymmetrical settlement due to horizontal earth pressure typically results in rotational movement. This occurs when different parts of a structure settle unevenly due to varying earth pressures acting upon them. When one side of a bridge or structure settles more than another, it can create a pivoting effect, causing the entire structure to rotate about a point. This rotational movement can lead to significant structural issues, including changes in alignment and potential instability.

In contrast, vertical movement tends to be uniform and is not directly caused by unsymmetrical conditions. Lateral movement refers to horizontal shifts and does not encompass the aspect of rotational pivoting caused by differential settlement. Tractive movement is more commonly associated with forces acting on vehicles or materials in motion rather than the effects of settlement on bridge structures. Hence, the key characteristic of unsymmetrical settlement leading to a pivoting or rotating action establishes why rotational movement is the accurate response.