Which term is used to describe the axis of a bridge that runs from abutment to abutment?

• A. Maintenance
• B. Longitudinal
• C. Luminaire
• D. Local Buckling

Answer: (B)

In bridge terminology, directions are described along the longitudinal, transverse, and vertical axes. The axis that runs from one abutment to the other follows the length of the bridge span, so it’s the longitudinal axis. This lengthwise direction is where the primary bending and shear effects from loads along the span are analyzed, and it contrasts with the transverse direction, which goes across the bridge, and the vertical axis, which is up and down. The other terms here don’t describe an axis: maintenance is about keeping the structure in service, luminaire refers to lighting, and local buckling is a failure mode of slender plates or members. So the axis from abutment to abutment is the longitudinal axis.