混凝土梁桥火灾后检测评估研究  

Inspection and Assessment of Concrete Girder Bridge Damaged by Fire

作　　者：蔡正东[1,2] 彭旭民[1,2] 黄清[1,2] 

机构地区：[1]中铁大桥局集团桥科院有限公司,湖北武汉430034 [2]桥梁结构安全与健康湖北省重点实验室,湖北武汉430034

出　　处：《世界桥梁》2014年第6期74-78,共5页World Bridges

摘　　要：某预应力混凝土高架桥火灾后受到损伤,为了制定维修措施,对火灾后桥梁进行检测评估。表观检测发现箱梁底板、腹板、翼缘板和桥墩墩身混凝土均有破损;综合热分析和X射线衍射分析得到桥梁火灾时的灼着温度;在箱梁火烧后的腹板处取芯样进行混凝土轴心抗压强度试验,截取过火后露出的主筋进行钢筋抗拉力学性能试验,得到的结果均满足规范要求;对受损前、后桥梁线形进行对比分析,桥梁未见明显下挠;动力特性测试结果显示火灾后桥梁整体刚度明显降低。依据检测结果及采用有限元软件计算得到的结构检算结果,判定该桥属危险构件,必须立即采取加固措施或拆除。A prestressed concrete viaduct has been damaged in a fire disaster .To formulate remedial measures ,the condition of the bridge after the fire disaster was inspected and evaluated . The visual inspection reveals that concrete in the box girder base slabs ,webs ,flanges and pier shafts all has been damaged .By combined use of the thermal analysis and X ray diffraction ,the burning temperature of the bridge in the fire was gained .Core samples are cut from the webs of the box girder experiencing fire ,to which axle compressive strength test was done .The exposed reinforcement experiencing fire was cut down to do reinforcement tensile strength test .The results of these two tests all agree with the code requirements .The geometries of the bridge before and after the damage were compared and analyzed ,no significant deflection is found on the bridge .The dynamic test results show that the overall stiffness of the bridge after the fire distinctively reduced .According to the inspection results and the checking results by finite element software calculation ,the bridge is identified as a dangerous structure ,w hich must be rehabilitated or dismantled .

关 键 词：混凝土桥梁 火灾 受损 灼着温度 强度 结构检算 评估 等级评定 

分 类 号：U445.71[建筑科学—桥梁与隧道工程]