预应力混凝土T梁防纵裂的保护层厚度计算

Calculation of Protective Layer Thickness for Preventing Longitudinal Cracks of Prestressed Concrete T-Beam

讨论了引起混凝土预应力T梁纵向开裂的原因,分析了张紧的预应力钢束对梁体上拱变形的反向作用和受压混凝土由泊松效应引起的横向拉应变作用,并结合理论分析和数值方法提出了考虑上述作用下T梁预应力管道的最小保护层厚度的计算公式。

The causes of longitudinal cracks of prestressed concrete T-beam are discussed. The great transverse tension stress on the bottom floor caused by the reversed effect of tensional prestressed steel bar on up-flexion of T-beam and the overlapping enhancing Poisson effect are analyzed. Combining with theoretic analysis and numerical computing method, a formula is deduced to compute the minimum protective layer thickness of the prestressed pipeline under the disadvantageous stress.