Which category of loads arises from gradual changes in material properties such as creep or shrinkage of concrete?

• A. Deformation Stresses
• B. Seismic Loads
• C. Bridge Loads
• D. Live Load

Answer: (A)

Time-dependent behavior of concrete, such as creep and shrinkage, causes gradual deformation. If the structure restrains these changes, the resulting movement induces internal stresses. These are deformation stresses—internal stresses generated by the material's gradual change, not by external forces like moving loads, earthquakes, or the permanent weight of the structure. This long-term, restraint-induced effect is important for design because creep and shrinkage can alter stresses, deflections, and crack patterns over time, especially in reinforced or prestressed concrete.