超长多跨预应力梁张拉过程分析

Analyzing stretching process in prolongs prestressed beam

多跨预应力梁的预应力索由于超长、多波,因而与孔道壁之间的摩擦引起的预应力损失就较单跨梁中的损失要严重,而且摩擦损失将占总的预应力损失的绝大部分。可以认为,按规范预应力摩擦损失计算公式计算所得结果和实际损失值有较大的偏差。本文作者根据现场一多跨预应力梁张拉过程的监测,结合有限元计算对实测值的修正,得出多跨预应力梁的摩擦系数与规范上的差别,对规范建议的摩擦系数取值提出讨论。

As prestressed wire prolongs multispan and multiwave,the loss of prestress due to friction between the wire and hole is more server than in single span beam.Friction loss is the mostly among all loss,and the disparity between real loss and the calculated one according to formula suggested in concrete code is obvious.The paper,based on monitoring of a multispan prestressed reinforced concrete beam in field,and combining modification to measured loss by FEM calculation,derives out the difference between real coefficient of friction and the value in concrete code,and brings out suggestion on the value of friction coefficient.