Nonlinear analysis method for continuous post-tensioned concrete members with unbonded tendons

The unbonded post-tension (UPT) method has been often applied to continuous flexural members (e.g., slabs and beams), where tendons are typically placed continuously through the supports. Most of the previous studies, however, focused on simply supported UPT flexural members, whereas little research has been performed on continuous UPT members. Moreover, as the few existing studies on continuous beams mainly aimed at strength prediction, the results of these studies are not applicable to examine the service load behavior of UPT members. They also did not reflect the moment redistribution phenomenon in continuous members, which is quite important to accurately predict the flexural strength and behavior of continuous UPT members. Therefore, in this study, a flexural behavior model for continuous UPT members has been proposed, which is a nonlinear analysis model that reflects the moment redistribution. The accuracy of the proposed analysis model was also verified by comparing to the test results of continuous UPT members that included over-reinforced members, internally and externally post-tensioned members, and the members with diverse tendon profiles and various sectional shapes.

► A nonlinear analysis method for the flexural responses of UPT members was derived.
► Moment redistribution effect in UPT continuous member was reflected in this model.
► The curvature distribution was simplified to obtain the stresses in unbounded tendons.
► The accuracy of the proposed model was verified by comparing to the test results.