Which option correctly lists the typical components of a steel multi-girder bridge's superstructure and substructure?

• A. Superstructure includes deck, steel girders, diaphragms/stiffeners, cap beams, bearings; Substructure includes piers, abutments, foundations, bearing seats, and footings/piles.
• B. Superstructure: deck, steel girders, diaphragms/stiffeners, cap beams, bearings; Substructure: piers, abutments, foundations, bearing seats, substructures (footings/piles).
• C. Superstructure includes deck, girders, diaphragms only; Substructure includes piers and abutments only.
• D. Superstructure includes deck and bearings only; Substructure includes piers, abutments, foundations.

Answer: (B)

In a steel multi-girder bridge, the load-path is split between what sits above the deck (superstructure) and what transfers loads to the ground (substructure). The superstructure includes the deck, the main steel girders, lateral bracing elements such as diaphragms or stiffeners, cap beams that distribute loads at connections, and bearings that allow controlled movement at supports. The substructure encompasses the supports and foundations that carry those loads down, including piers and abutments, the foundations themselves, bearing seats where the bridge bearings rest, and footings or piles that transfer loads into the soil. This option correctly pairs deck, girders, diaphragms/stiffeners, cap beams, and bearings with the superstructure, and lists piers, abutments, foundations, bearing seats, and footings/piles as substructure components, with the footings/piles clearly identified as part of the substructure. The other listings either omit essential elements or misplace components (for example, misclassifying bearings or omitting diaphragms/stiffeners or cap beams), so they don’t provide the accurate division of typical components.