FDOT Plan Reading Practice Exam - Florida Test Prep & Study Guide

The term that describes the distance between two substructures is "span." In the context of civil engineering and bridge design, the span refers to the horizontal distance between two support points, such as piers or abutments. This measurement is crucial for determining the structural integrity and design requirements of a bridge or similar structure. The span influences factors such as load distribution, the required materials, and the overall design, ensuring that the structure can support the anticipated forces and stresses.

While the other options pertain to measurements or distances, they are not specific to the context of substructures. The interval may refer to a period of time or a distance in a different context, while length generally describes a one-dimensional measurement without the specific application of bridges or substructures. Chord can relate to a specific segment in a curve, particularly in geometry, but it does not denote the distance between two substructures in engineering terminology. Thus, span is the most precise and applicable term in this scenario.