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与部分预应力混凝土梁相比,全预应力混凝土梁全截面受压且压应力较高,由于混凝土收缩徐变产生的梁长期变形也更大。该文从按龄期调整的有效模量法出发,将梁沿长度方向细分单元,细分单元长度为截面高度的1倍~2倍,锁定单元节点,分别计算混凝土的收缩、徐变以及预应力筋的松驰对其产生的强迫力值;释放强迫力,并将其反向作用于节点上,求出此时的截面时随应变和附加曲率,进而推导出可用于求解任意时刻的全预应力混凝土梁长期变形的计算公式。基于该课题组和其他研究者试验结果,对该文及国内外规范的计算公式进行了对比分析,结果表明:该文公式计算值与试验结果吻合良好;国内外规范计算值与试验结果的平均误差则明显偏大,且计算结果偏于不安全。
Compared with the partially prestressed concrete beams, the full prestressed concrete beams are under full compression and high compressive stress, and the long-term deformation due to shrinkage and creep of concrete is also larger. Based on the age-adjusted effective modulus method, the length of the beam is subdivided into units, and the length of the subdivision unit is 1 to 2 times of the height of the section. The unit nodes are locked to calculate the concrete shrinkage, creep and The force of the prestressing tendon slackening to it; releasing the forced force and acting on the node in the opposite direction, obtaining the cross section with strain and additional curvatures at this time, and then deducing the force that can be used to solve any moment Calculation formula of long - term deformation of full prestressed concrete beams. Based on the experimental results of this research group and other researchers, the comparative analysis of the calculation formula of this article and that of domestic and foreign norms is made. The results show that the calculated value of the formula is in good agreement with the test result. The average of the calculated value at home and abroad and the test result The error is obviously larger, and the calculation result is unsafe.