Final answer:
The stress loss is generally less in pretensioning compared to post-tensioning due to the pre-stressing of steel strands before the concrete is poured which ensures a more uniform stress distribution.
Step-by-step explanation:
The stress loss is usually less in pretensioning than in post-tensioning. This is because pretensioning involves stressing the steel strands before the concrete is cast, leading to a more even distribution of tension which minimizes later losses. In contrast, post-tensioning applies stress to the steel strands after the concrete has hardened, which can introduce additional stress losses due to friction and elongation of the tendons as they are tensioned. Factors such as bonding, differential shrinkage, and creep can also contribute to varying levels of stress loss in both methods. However, proper design and execution can help mitigate these effects and optimize the structural integrity and longevity of the construction.