无黏结预应力高性能粉煤灰混凝土桥梁疲劳损伤计算方法的研究

Study on Computational Method of Fatigue Damages of Unbonded Prestressed High Performance Fly Ash Concrete Bridges

结合洛湛线工程项目,以不同掺量的高性能粉煤灰混凝土无黏结预应力桥梁的疲劳试验为基础和基于结构变形的方法计算无黏结预应力筋增量,提出一种考虑钢筋和混凝土两种材料耦合作用的非线性疲劳损伤过程分析方法。该方法可以考虑由于组成材料损伤机制不同而造成的疲劳损伤过程中的应力重分布现象,通过分段线性的方法进行混凝土构件的非线性损伤过程分析。理论分析与试验结果比较表明,该方法能够较好地描述无黏结预应力混凝土梁疲劳损伤的全过程,并能给出更符合实际情况的疲劳寿命。

Construction of the Luoyang-Zhanjiang Railway is applied in study. On the basis of the results of fatigue experiments of unbonded prestressed concrete beams with different mixture ratios of high-performance fly ash and the unbonded prestressed reinforcement increments calculated by the method of structural deformation, the nonlinear analysis method of fatigue damage processes of unbonded prestressed concrete beams is proposed, which takes into account the coupling action between concrete and reinforcement. The method covers stress redistribution in the fatigue damage process caused by different damaging mechanisms of constituent materials. The nonlinear damage process analysis of concrete members is achieved by means of piecewise linearity. Comparing theoretical analysis with experimental results, it is seen that the proposed method is able to well depict the whole fatigue damage process of unbonded prestressed concrete beams and predict the fatigue life more realistically.