Abstract: Aimed at the condition flmt mainstream can not smoothly get through the bridge opening in the engineering，which induced bridge destruction，al1alyze file reason of causing the malmtream variance ofthe flood in front ofthe bridges． Taking bearing and conical slope as examples explains tile destruction mechanism of variant mainstream，propose the corresponding countermeasure of disaster prevention and mitigation．

Key words: bridge structure, mainstream variance, beating, destruction

摘要： 针对工程中囚主流不能按原设计流向顺适通过桥孔而导致桥梁水毁的情况，分析了引起桥前洪水主流变异 的原因，并以支座和锥坡为例说明变异主流的破坏机理，进而提出相应的防灾减灾对策．

关键词: 桥梁结构, 主流变异, 支座, 破坏