预应力筋非线性松弛对连续刚构桥的影响

Influence to Continuous Rigid Frame Bridge by Non-linear Relaxation of Prestressed Reinforcement Bar

基于前期研究建立的非均匀预应力筋松弛损失简化计算模型,以某跨越大渡河桥梁为研究对象,对预应力混凝土连续刚构桥进行主梁施工全过程应力和挠度变化数值模拟,分析由于施工控制不当引起的非均匀预应力筋非线性松弛对成桥线形和控制截面预应力度的影响。另外,通过改变预应力筋锚下有效预应力离散程度的大小来模拟预应力施工质量控制的变异,结果表明:预应力筋锚下有效预应力离散程度增大对预应力混凝土连续刚构桥主梁的预应力度和成桥线形均有直接负面影响。因此,在桥梁工程中应对其予以足够重视并针对性地采取预应力精细化施工控制措施。

Based on noneven prestress reinforcement bar relaxation loss simplified calculation model set up before,this paper took certain bridge on Dadu River as study object,to carry out numerical simulation of whole process stress and flexibility variation of main beam construction of prestressed concrete continuous rigid frame bridge,so to analyze influence to bridge linearity and control section prestress by nonevent prestress reinforcement bar non-linear relaxation caused by improper construction control.Besides,through changing the value of effective prestress dispersion degree under prestressed reinforcement bar,result shows that the increasing of effective prestress dispersion degree under prestressed reinforcement bar has direct negative influence to prestress degree of prestressed concrete continuous rigid frame bridge main beam and bridge linearity.Therefore,these factors must be emphasized in bridge project and prestress precise construction control measures shall be taken accordingly.