某大桥靠岛岸侧的5×35 m连续梁引桥于2012年某日凌晨3时左右遭受火灾。为恢复该桥的使用功能，针对火损后的桥跨进行现场检测，并结合火场温度和结构温度场的模拟分析，对结构的受损程度进行综合评定。结果表明箱梁表面有较大面积的混凝土崩落，且造成钢筋外露，受火灾影响最为严重的是内侧翼板处，因火损导致8根横向预应力钢绞线外露。在此基础上针对箱梁混凝土火损后剥落采取砂浆修补或灌注并结合粘贴锚固钢板的措施；针对翼板横向预应力火损采取增设钢结构隔板的措施；针对结构整体采用张拉粘贴预应力碳纤维板的措施进行维修加固。经试验评定，验证了加固方案实施后的桥梁承载能力得以恢复。%T he 5 × 35‐m span continuous girder approach bridge of a bridge on the island bank side caught fire at about 03 :00 in the early morning in a day in 2012 .To restore the operational function of the bridge ,the fire damaged spans of the bridge were inspected in the field ,the fire temperatures and temperature fields of the structure were simulated and analyzed and the damage degrees of the structure were comprehensively assessed .The results of the assessment show that rather great area of concrete spalling occurs on the surface of the box girder of the bridge and the concrete spalling causes the exposure of the reinforcement .The part of the box girder affected most severely by the fire damage is the inner side cantilever slab w here 8 transverse prestressing steel wire strands are exposed owing to the fire .According to the assessment ,the concrete spal‐ling of the box girder is repaired by the measure of plastering or grouting the cement mortar and binding the anchor steel plates .The damaged prestressing steel wire strands of the cantilever slab are repaired by the measure of adding the steel partition plates and the w hole structure is repaired and strengthened by the measure of binding and tensioning the prestressing carbon fiber reinforced polymer (CFRP) plates .The further tests and assessment prove that the load‐bearing capacity of the bridge has been restored after all these measures are taken .
展开▼
