施工误差对预应力变截面箱梁底板受力性能影响分析

Analysis of Mechanic Behavior of Bottom Slabs in Pre-stressed Concrete Box Girders Bridges with Variable Sections Influenced by Construction Errors

在近几年预应力混凝土箱形连续梁(刚构)桥施工中,常出现箱梁底板在合龙束张拉过程中发生沿底板孔道上下层混凝土整体破坏的工程事故。以往研究主要从构造设计角度对事故原因进行分析。本文利用空间有限元程序ANSYS的子模型功能,分析了施工过程中常见的误差对箱梁底板受力性能的影响程度。研究表明,底板合龙束预应力孔道定位误差、箱梁悬臂端合龙高差都对箱梁底板竖向和横向应力影响显著,尤其是波纹管定位偏高的情况更为明显,施工中应予以避免。

During the process of closure in main span of long-span concrete bridges,serious accidents like concrete near pre-stressing ducts completely damaged and bursts into two parts happen frequently in recent years.So far,reason analysis on the accidents has been carried out from the view of construction design.By using sub-model function of program ANSYS,stress state of curved bottom slabs influenced by common construction errors was performed.Research results showed that both the location error of pre-stress ducts and the closure height difference between cantilever arms affect vertical and horizontal stress of curved bottom slabs obviously,especially for the case with higher location of pre-stress ducts than design.It should be avioded in construction process.