Which item is listed as a Transient Load?

• A. Downdrag force
• B. Creep
• C. Shrinkage
• D. Water load and stream pressure

Answer: (D)

Transient loads are external forces whose magnitudes change with time due to changing conditions, such as fluids whose levels or pressures vary. Water-related loads on a bridge—like hydrostatic pressure from water at different depths and dynamic pressure from flowing water—fit this idea because they can rise and fall with river stages, flood conditions, or flow velocity. Because of that time-varying nature, water load and stream pressure are classic examples of transient loads.

Downdrag arises from soil-structure interaction as the foundation settles and the surrounding soil drags the footing downward; this is a static, long-term interaction effect rather than a time-varying external load. Creep and shrinkage are time-dependent deformations within concrete itself, not external forces acting on the structure at a given moment. They influence long-term behavior but aren’t transient loads applied to the structure.