基于车激响应的桥梁支座脱空病害识别方法研究

为快速、准确地评估铁路简支梁桥的支座健康状态,分析各影响因素对识别结果的影响,以刚体动力学和结构有限元法为基础建立了车桥耦合动力分析模型,提出了一种以频谱相似性指标构建目标函数、以模型修正方法为主要技术手段的桥梁支座脱空病害识别方法,并在此基础上以某高速铁路32m简支梁桥为工程背景,采用数值模拟和现场试验的方式对所提方法进行了验证。结果表明:该方法可实现支座脱空病害的定位和定量识别,且计算效率和精度均较高,虚假损伤很小;列车行车速度、轨道不平顺谱及列车编组等因素对支座脱空病害识别结果影响较小;现场试验的加速度频谱分析实测值与理论值在低频段吻合良好,各支座识别结果均大于支座刚度限值,支座未发生脱空病害,与支座实际状态一致。

Study of Methods to Identify Bridge Bearing Disengagement Based on Vehicle-Excited Responses

To rapidly and accurately evaluate the health condition of the bearings of railway simply-supported beam bridge and analyze the effect of different influential factors on the damage identification results,the model for vehicle-bridge coupling dynamic analysis based on rigid dynamics and structural finite element method was built.A bridge bearing disengagement identification method using the spectral similarity index to fit the objective function and taking the model updating method as principal technical means is proposed,and on the basis of which,a high-speed railway simply-supported beam bridge with spans of 32 m is taken as the background project to verify the method aforementioned via numerical simulation and field tests.The results show that the method can realize the positioning and quantitative identification of the bearing disengagement damage with high calculation efficiency and accuracy as well as minor chance of releasing fake damages.The factors,like train speed,track irregularity spectrum error and train marshaling,have minimal influence on the bearing disengagement identification results.The acceleration spectrum results gained from field tests agree well with the theoretical ones within the low frequency band.The identification results of each bearing are bigger than the limits of bearing rigidity,no bearing disengagement damage is observed.The theoretical condition of the bearing is consistent with the condition of the real bearing.