This load combination is applicable to the longitudinal analysis of tensile stresses in prestressed concrete superstructure components.

• A. Service I
• B. Fatigue and Fracture limit states
• C. Service III
• D. Extreme Event II

Answer: (C)

Longitudinal tensile stress in prestressed concrete members under service conditions is governed by a serviceability load combination that represents how the member is loaded over time, including the effects of the prestressing and long-term factors. The Service III combination is the one designated for checking tensile stresses along the length in this context, because it reflects the typical in-service interaction of dead load, live load, and prestress effects in a way that can cause tension in the longitudinal fibers. This makes it the appropriate choice for evaluating whether the tensile stress remains within allowable limits and cracking criteria.

Extreme Event II is about rare, extreme conditions and not the usual service behavior. Fatigue and Fracture limit states address different failure modes under cyclic loading, not the steady longitudinal tension check described here. Service I and Service II pertain to other serviceability checks or loading patterns, but for longitudinal tensile stress in prestressed superstructures, the designated serviceability combination is the one used for that analysis.