Flexural behavior of steel I-beam prestressed with externally unbonded tendons

The external post-tensioning technique has been commonly used in the construction field because it facilitates the analysis of structures and is widely applicable for many types of structures. In this paper, the flexural behavior and strengthening effect of a bridge were studied using a steel I-beam that had been externally prestressed with unbonded tendons. Eleven steel beams were fabricated and tested in terms of the tendon type, the amount of tendon or prestressing force, the installation of a deviator, and the embedment of a draped tendon. The results show that the externally prestressing method creates a stiffer steel beam when the proper amount of prestressing force is applied and when detail techniques are appropriately combined.The experimental results were compared to a theoretical solution in order to verify whether the external post-tensioning method is useful for strengthening a steel bridge and whether it is applicable in the construction field.