在役预应力混凝土箱梁开裂后承载力评估

Evaluating System of Bearing Capacity for Existing Cracked Prestressed Concrete Box Girder Based on Crack Feature

摘要:

针对目前大量存在的在役预应力混凝土箱梁桥跨中下挠和开裂的现象，基于主要受力裂缝的外观统计特征，通过构造两类损伤单元，即正裂缝区损伤单元和斜裂缝区损伤单元，采用刚度折减和引入平面刚架模型的方法，建立了基于裂缝统计特征参数的损伤预应力混凝土箱梁计算模型，提出了基于截面刚度变化的预应力混凝土箱梁桥截面有效刚度折减系数和基于混凝土受压区应力变化程度的承载力折减系数，从而实现了对在役预应力混凝土结构开裂损伤后，在其使用过程中的受力性能评价.

Abstract:

According to the over deformation and cracking of the prestressed concrete(PC) box girder bridge,vertical crack and oblique crack damage element were constituted based on primary appearance statistical cracks caused by force,two damage elements.Then the simulation calculation model of damaged PC bridges was put forward by reducing the rigidity and introducing planer rigid model.Finally,the rigidity reduction coefficient and capacity reduction coefficient were proposed to assess the structure capacity of existing damaged PC bridges.