Which term refers to the prestressing force applied before pouring concrete?

• A. Post-tensioned Girder
• B. Pretensioned Girder
• C. Prestressed Girder
• D. Precast

Answer: (B)

When the prestressing force is applied before pouring concrete, the method is pretensioning. In this approach, the steel tendons are stretched and anchored while they’re still outside or at the formwork, and concrete is cast around them. After the concrete hardens, the tendons are released, transferring the compressive force into the concrete and leaving the member in a state of compression. The feature described by this question is embodied in a pretensioned girder, which is the name for a member built using that pre-pour prestress. This is different from post-tensioning, where the tendons are tensioned after the concrete has been poured and gained strength. Prestressed girders is a general term and does not specify when the prestress is applied, while precast refers to factory fabrication rather than the timing of prestressing.