某环形立交桥断桩病害分析及维修加固方案

Broken Pile Disease Analysis of a Ring Overpass&Its Maintenance Reinforcement Scheme

某环形立交桥匝道发生断桩,其病因为桥墩和桩基连接位置浇筑质量差,导致主梁下挠达16.7 cm;主梁顶底板开裂贯通腹板,最大裂缝宽度达0.6 mm。通过对裂缝宽度反算钢筋应力发现:当裂缝宽度大于0.3 mm时主梁内钢筋已屈服,TA1墩顶主梁底板、TA0和TA2墩顶主梁顶板严重开裂区域钢筋已屈服甚至断裂。针对这些病害,桥墩采用新增桩基承台、重新浇筑桥墩加固方案;主梁底板和腹板结合粘贴钢板法和碳纤维布法进行加固,对顶板开裂区域采用凿除桥面铺装密布主筋并重新浇筑提高承载力。加固后桥梁已正常运营十多年,可为类似工程提供参考和借鉴。

A broken pile occurred on the ramp of an interchange bridge,and the cause was poor pouring quality at the connection between the pier and the pile foundation,which resulted in a deflection of the main beam of 16.7 cm;the cracking of the main beam top and bottom plate penetrated the web,with a maximum crack width of 0.6 mm.By calculating the steel stress from the crack width,it was found that when the crack width was greater than 0.3 mm,the steel in the main beam had already yielded,and the steel in the severely cracked areas of the main beam bottom plate on the top of pier TA1,the main beam top plate on the top of pier TA0 and TA2 had already yielded or even fractured.In response to these defects,the pier was reinforced by adding a pile cap,and the pier was reinforced by re-pouring.The main beam bottom plate and web were reinforced by bonding steel plates and carbon fiber cloth,and the cracked area of the top plate was reinforced by chiseling the bridge deck pavement,covering it with main reinforcements,and re-pouring to improve the bearing capacity.After the reinforcement,the bridge has been in normal operation for more than ten years,which can provide reference for similar projects.