有黏结与无黏结混合配置预应力筋混凝土梁 短期刚度研究.

This paper presents an in-depth study on the short-term stiffness of hybrid prestressed concrete beams with bonded tendons and unbonded tendons. Calculation formulae of short-term stiffness were derived based on the double line theory. Multiple regression analysis is conducted for the reduction coefficient β0.5 used for the termination point of the stiffness calculation, based on the finite element results of 71 beams. Two formulae for the short-term stiffness of the hybrid prestressed concrete beams were proposed based on two different ways of calculating β0.5. The test data of 42 unbonded prestressed concrete beams and 31 bonded prestressed concrete beams collected from existing literatures verified the proposed stiffness formula. It’s suggested that the proposed formulae for short-term stiffness can also be applicable to bonded prestressed concrete beams and unbonded prestressed concrete beams. In addition, this paper presents an assessment of the accuracy of design formulae provided by a number of design standards, including GB 50010—2010, ACI 318-11, EN 1992-1-1:2004, for the short-term stiffness of prestressed concrete flexural members. [ABSTRACT FROM AUTHOR]