Stress at Ultimate in Unbonded Post Tensioning Tendons for Simply Supported Beams: A State-of-the-Art Review

An in depth State-of-Art Review is done on the topic, Stress at Ultimate in Unbonded Post tensioning Tendons. Simply supported members are used for discussion. Prediction equations proposed to compute the stress in tendons at ultimate, f ps are reviewed. Six data sets are used to analyse the prediction equations and the results discussed. In addition, the parameter Δ f ps is compared with plastic hinge length on the basis of Δ f ps is directly related to the plastic hinge formation that occurs from yielding of nonprestressing steel to the concrete crushing in the extreme compressive fiber. Acceptable trend is obtained from the comparison. Further, stress in external tendons are reviewed and discussed based on the review of internal unbonded tendons.