某城际铁路混凝土桥墩火灾后检测评估与处治  

Inspection and Remedial of a Concrete Pier of a Viaduct Accommodating Intercity Railway After a Fire Disaster

作　　者：邹春蓉[1] 任东华[1] 胡安庆[1] 熊文豪[1] ZOU Chun-rong;REN Dong-hua;HU An-qing;XIONG Wen-hao(China Railway Southwest Science Research Institute,Ltd.,Chengdu 610031,China)

机构地区：[1]中铁西南科学研究院有限公司,四川成都610031

出　　处：《世界桥梁》2022年第6期116-121,共6页World Bridges

摘　　要：某城际铁路高架桥一圆端形混凝土桥墩发生火灾,桥墩过火时间约12 min。为了解火灾对桥墩的影响并指导后续维修处治,对火灾现场进行调查,并对混凝土抗压强度、碳化深度、内部缺陷,以及钢筋保护层厚度和墩身垂直度进行专项检测;基于检测结果与温度场分析对材料性能与几何参数进行折减,采用有限元法分析桥墩承载能力;根据桥墩火灾后评估结果,对桥墩进行外包混凝土加固处治。结果表明:火灾仅造成墩身过火区域混凝土剥落,最大剥落深度4 cm;过火区域和未过火区域混凝土抗压强度未出现明显差异,碳化深度较小,混凝土弹性波速度变化不大,内部整体较为均匀;火灾高温最大影响深度55 mm,对钢筋的力学性能影响不大;墩身垂直度满足规范要求;墩身混凝土剥落区受火最高温度为500~700℃,未剥落区混凝土受火最高温度低于300℃;火灾后墩身混凝土压应力变化不大,墩顶纵向水平线刚度略有降低,墩顶水平位移有所增大,但均满足规范限值要求;该桥处治后,运营至今使用正常,处治效果良好。A round-cornered concrete pier of a viaduct accommodating intercity railway was set on fire and burnt for about 12 minutes.To investigate the influence of the fire disaster on the pier and guide the consequential remedial,the fire disaster scene was inspected,and the inspection specifically focused on the concrete compressive strength,carbonization depth,inner defects,concrete cover thickness and the perpendicularity of the pier shaft.Based on the inspection results and the temperature field analysis,the material performance and geometry parameters were discounted.The load bearing capacity of the pier was analyzed by the finite element method.As per the assessment,it was determined to remedy the pier via encasing concrete.It is shown that the pier shaft exposed to the fire suffered concrete spalling,with the maximum spalling depth reaching 4 cm.The compressive strengths of the concrete exposed and hidden from the fire did not show notable difference.The carbonization depth is small,and the elastic wave velocity of the concrete showed minor changes and the concrete of the pier shaft was uniform over height.The maximum influence depth of the high temperature of the fire disaster is 55 mm,with minimal influence on the mechanical property of the reinforcement.The perpendicularity of the pier shaft met the code requirements.The maximum temperature in the concrete spalling zone of the pier shaft was between 500 ℃and 700 ℃,but in the zone without concrete spalling,the maximum temperature was less than 300 ℃.After the fire disaster,the compressive strength of the pier shaft exhibited minimal change,the rigidity of the pier-top longitudinal and horizontal lines is slightly lowered,and the horizontal displacement at the pier and superstructure interface is improved to a degree,but also meets the limits given in the code.After remedial,the bridge has been in good service condition.

关 键 词：城际铁路 混凝土桥墩 火灾 检测 温度场 力学性能 评估 处治 

分 类 号：U443.22[建筑科学—桥梁与隧道工程] U445.7[交通运输工程—道路与铁道工程]