Which are the three principal categories of bridge loadings?

• A. Dead load, Torsion, Shear
• B. Dead Load, Primary Live Load, Secondary Live Load
• C. Dead Load, Live Load, Wind Load
• D. Primary Live Load, Wind Load, Seismic Load

Answer: (B)

The main concept here is how bridge loads are grouped for design. Bridges endure a permanent weight from all components and attachments, which is the dead load—the fixed, lasting part of the structure’s load. Then there’s the primary live load, the main variable load from moving traffic and pedestrians that the bridge is expected to carry in normal service. Finally, secondary live load accounts for additional variable effects that are less frequent or less intense but still need to be considered, such as parked vehicles, maintenance activities, or unusual load configurations during staging or construction. This three-part framework—dead load, primary live load, and secondary live load—lets engineers analyze typical usage and less common scenarios with appropriate safety factors. Other groupings tend to mix in environmental or seismic loads or split live loads differently, which is why this option aligns best with the stated categories in this context.