用分段逼近法计算混凝土收缩与徐变引起的构件预应力损失

THE METHOD OF PROGRESSIVE APPROACH FOR TIMEDEPENDENT LOSSES OF PRESTRESSED CONCRETE MEMBERS

  • 摘要: 因混凝土收缩与徐变引起的预应力损失在总损失中占的比重很大,我国规范中对这部分损失的求解给出了经验公式,本文提出了分段逼近法可求解先张法预应力混凝土轴心受拉构件,任一时间因收缩和徐变引起的预应力损失,并同时考虑了非预应力筋的影响;方法中,把总时间分段,各时段中设应力为常数,求解各时段因收缩和徐变引起的预应力损失,再叠加求总损失,这样,可求出预应力损失较精确值:混凝土收缩与徐变求解采用了作者导出的一组公式。

     

    Abstract: The time-dependent losses of prestressed concrete members are significant. The present Chinese Standard only gives the empirical formula to solve for these losses. This paper describes a method of progressive approach for prestress losses of axial-loaded concrete members. The method is based on the incremental superposition procedure in which the stresses due to creep and shrinkage are assumed to yare discretely at selected instants of time. The total prestress losses consist of the sum of the loss between instants of time. The method can give the accurate value of prestress losses. The factors of the stains due to creep and shrinkage are also given by the authors.

     

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