铁路钢筋混凝土拱桥使用安全现状评估

Durability Assessment on Railway Reinforced Concrete Arch Bridge

研究目的:由于外荷载、自然灾害、混凝土老化、钢筋锈蚀等内外因素的影响,既有铁路钢筋混凝土拱桥存在不同程度的损伤,将直接影响结构的安全性能和承载力。本文以某铁路拱桥为工程背景,采用模糊层次分析方法,结合现场检测数据,评估其上部结构的耐久性。研究结论:(1)层次分析法将复杂的目标问题分解为各组成要素,并根据支配关系将这些要素进行分组,形成一个层次结构;而模糊层次分析法将模糊评判法和层次分析法二者有机结合起来,强调事物的模糊性,同时用精确的数学语言表达;(2)依据现场检测结果,建立结构的层次体系模型,对不同构件的耐久性指标赋予不同的权重系数,铁路钢筋混凝土拱桥综合评估结果为Ⅰ级;(3)评估结果与现场检测结果一致,此方法评价结果能够反映整体结构中主要构件的健康状态,具有实用性、科学性和客观性;(4)本研究成果可用于指导桥梁设计和维护,从而延长桥梁的使用寿命。

Research purposes： A large number of railroad reinforced concrete arch bridges in service stage are damaged by load,natural disaster,concrete ageing,and steel bar corrosion.The bearing capacity inadequate,ageing and damage problems caused by durability damage will directly threaten the safety performance of the structures and the carrying capacity.Taking a railway arch bridge as an engineering background,the durability is studied to assess the structural health based on the fuzzy hierarchy method and field test results.Research conclusions：（1） Analytic hierarchy process can decompose the complex target problems into various factors,and these factors are grouped according to the control relationship.Fuzzy analytic hierarchy process is combined with the fuzzy evaluation method and analytic hierarchy process,and emphasizes the fuzziness and precise mathematical expression.（2） The hierarchy model of the railway arch bridge is established according to the field test results,the durability indexes of different components are given different weight coefficients.The comprehensive evaluation result for the railway arch bridge is grade Ⅰ.（3） The evaluation results are consistent with the field test results.So the assessment results by fuzzy analytic hierarchy process can reflect the health of the important components.It has thecharacteristic of practicability,scientificity and objectivity.（4） The research results can be used to guide the bridge design and maintenance to prolong the service life of bridges.