Numerical and Analytical Behavior of Beams Prestressed with Unbonded Internal or External Steel Tendons: A State-of-the-Art Review

This paper presents a detailed state-of-the-art chronological account of past studies dating back to the late 1980s consisting of an overview of the vast majority of prediction equations for the stress at ultimate in prestressed unbonded internal or external steel tendons of simply supported concrete beams. The paper also details past studies carried out to investigate the complete nonlinear behavior of such beams throughout loading. Past and relevant studies were carefully reviewed in detail and then synthesized in the most reduced, yet accurately depicted, format in an effort to capture the pertinent highlights. For each review, the most relevant factors considered by the authors were highlighted, including span-to-depth ratio, second-order effects, length of the plastic hinge, friction and/or slippage at deviators, and experimental verification. An evaluation was carried out to compare and contrast the various nonlinear analysis studies using a simple tabulated format. Gaps were identified, and recommendations for future research were further proposed by the authors.