大跨径预应力混凝土箱梁桥长期变形不收敛成因分析

针对预应力混凝土箱梁桥长期变形不收敛的问题,文章先对几座典型病害桥梁实测变形与开裂病害进行了关联性分析,初步定性地指出跨中挠度的持续发展与裂缝扩展存在某种内在联系.然后选取一座具有代表性的桥梁为算例,采用ANSYS有限元程序,分别计算和分析了混凝土徐变、梁体开裂及裂缝扩展对长期挠度变化的影响.结果表明,桥梁长期变形发展特征是混凝土徐变变形与梁体开裂引发的变形耦合作用的结果;裂缝扩展是该类型桥梁长期变形持续发展的本质原因.

Cause Analysis of Long-Term Deformation without Convergence for Long Span Prestressed Concrete Box Girder Bridge

Aiming at long-term deformation without convergence for prestressed concrete box girder bridges, this paper made an association analysis of measured deformation and cracking disease of some typical diseased bridges. It indicated qualitatively that there were some internal relations between the progressive development of mid-span deflection and the evolution of cracks. Whereafter, a typical diseased bridge was selected as the computational model to study the long-term deflection caused by the concrete creep, cracking of girder body and evolution of cracks by ANSYS. The results indicated that： the development characteristics of long-term deflection at mid-span was a result of coupling of the deflection caused by concrete creep and the deflection caused by evolution of cracks; the evolution of cracks was the essential reason for long-term deflection without convergence for this type of bridges.