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Title |
Design of Additional Tendon Force and Evaluation of Resistant Moment for Prestressed Concrete Composite Section
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Keywords |
콘크리트 합성단면; 긴장력; 손실률; 콘크리트 장기변형; 저항모멘트; concrete composite section; prestressing force; loss rate; long-term deformation; resistant moment |
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Abstract |
A general composite section of precast and cast-in-place concrete with prestressed and nonprestressed reinforcements was analyzed to calculate residual stresses and loss of prestressing force caused by internal constraints of concrete long-term deformation. From the analytical results, equations to design additional prestressing force and to evaluate resistant moment of the composite section were proposed. The equations shows that the additional prestressing force can be over-estimated if the loss rate of the first prestressing force is over-estimated from the lumped sum of a design code. The analytical procedure with the proposed equations has been applied to a composite section using the AASHTO Type 5 girder. The loss rates of the additional prestressing force appling to the precast concrete girder was less than those appling to the composite girder. However, the resistant moment of the additional prestressing force on the composite girder was much larger than that on the precast concrete girder. The additional prestressing force appling to the composite section was very effective for strengthening of the prestressed concrete composite girder.
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