混凝土桥梁拼接后收缩徐变计算方法分析

为分析混凝土收缩徐变对新旧拼接混凝土桥梁的影响,考虑每个计算步长内由混凝土收缩引起的应力的徐变作用和混凝土的弹性模量变化,根据能量原理推导了混凝土收缩徐变的位移法基本方程。分别按每个计算步长内应力为变值和常值,采用增量法推导了每个计算步长内收缩徐变的递推计算公式,并编制了相应的计算程序。对比分析表明,按每个计算步长内应力为变值的计算结果与实测值吻合良好,与每个计算步长内应力为常值相比,可以增大计算步长,减少叠加次数,大大加快程序计算速度。

Analysis on calculating methods of shrinkage and creep effects of concrete widening bridge

For analysis of shrinkage and creep effects in old widening bridge,considering creep effect of stress aroused by concrete shrinkage and change of Yong's modulus at each time step,basic formula of shrinkage and creep was derived by displacement method,based on energy principle.Recursion formula of strain was developed by incremental method in condition of variable stress and constant stress in each time step separately,and calculating program was compiled,which is in agreement with test results.Compared with calculating results in condition of constant stress,time step on condition of variable stress can be enlarged to reduce calculating frequency and increase calculating speed of program.