组合梁中的时效行为计算分析

Calculation and Analysis of Time-dependent Behavior in Composite Beams

采用按龄期调整的有效模量,结合有限单元步进法,提出一种计算组合梁中时效行为的方法。该方法通过迭代法计算与时间有关的混凝土收缩徐变及力筋松弛引起的预应力损失。应用这种分析方法,编制相应的计算程序,进行一个组合框架及一座两跨连续组合梁的时效行为分析。结果表明,混凝土的收缩、徐变以及预应力损失对组合梁的应力重分布影响很大。

With the age-adjusted effective modulus method and the finite element step-by-step method, a method was brought forward to compute time-dependent behavior of composite beams, by which time-dependent prestress losses such as losses due to the shrinkage and creep of concrete, and losses due to relaxation of prestressing in the steel tendon can be computed by iterative method accurately. Using this analytical method, a program was worked out. Time-dependent behaviors of a composite frame in building and a composite girder bridge were investigated. The results show that the shrinkage and creep of concrete and losses of prestressing have significant effect on the redistribution of stresses in composite beams.