Title: Stress at Ultimate in Prestressed Unbonded Tendons: Assessment of Code Equations and Recommendation
Author(s): Maha Alqam, Fadi M. Alkhairi, and Antoine E. Naaman
Publication: Structural Journal
Appears on pages(s): 177-187
Keywords: bond reduction coefficient; external prestressing; fiber-reinforced polymer (FRP) tendons; stress at ultimate; unbonded tendons
Predicting the stress at ultimate unbonded prestressed tendons, fps, with reasonable success has been a challenge to researchers and code-writing organizations. This paper focuses on the detailed analysis of six code-related equations and recommends a new equation for code implementation applicable to both steel and fiber-reinforced polymer tendons. For an in-depth evaluation and comparison, the study uses the combination of five statistical measures: average, standard deviation, coefficient of correlation, least-squares deviation error, and percentage of predicted results falling below experimental test data. Analytical predictions are verified against their experimental counterparts on the basis of Δfps(not fps), and visual correlation graphs are provided for each equation analyzed.