【作者】 邹兰林；

【导师】 黄平明；

【作者基本信息】 长安大学 ， 桥梁与隧道工程， 2008， 博士

【摘要】 桥梁结构承载力动力评定方法一直是学术界研究的热点。以往桥梁结构承载能力动力评定方法研究主要通过室内试验回归单个构件刚度与频率之间的关系，以实测频率为指标来评定构件承载力，但是由于试验数据比较离散，没有得到统一的研究成果。目前，还没有一种成熟的动力评定方法能广泛的应用到实际工程中。板桥虽然跨径不大，但是其静载试验工作量大，寻求一种快速的评定方法对其承载力进行有效的评定具有很高的经济效益。基于此，本文在实际工程项目中选取189座板桥作为样本，通过对样本桥梁实测静载挠度、应变和动载频率进行统计回归分析，建立桥梁结构动载试验结果与静载试验结果之间的关系，通过桥梁结构动力特性来评定结构承载力，论文主要完成了以下几个方面的工作：(1)以样本桥梁实测数据为基础反演装配式板桥受力特性，确定各种型式装配式板桥的铰缝受力特点、桥面铺装层受力特点以及护栏沿桥面横向分配原则，以此建立真实反映装配式板桥受力特点的理论计算模型，为装配式板桥承载力评定提供理论计算依据。(2)系统分析结构不同病害位置、病害形态以及结构参数对装配式板桥动力特性的影响，并以样本桥梁试验结果验证了理论分析结果，为动力特性评定结构承载力奠定基础。(3)在研究结构挠度、频率与结构刚度之间关系的基础上提出名义频率校验系数概念，建立静载挠度校验系数和静载应变校验系数与动载频率校验系数之间关系，并以实桥动、静载实测数据为样本回归分析，建立装配式板桥挠度校验系数和应变校验系数与频率校验系数之间关系，对理论关系式进行修正。通过检算桥梁承载能力得到完好桥梁结构挠度和应变校验系数合理取值范围，以此来确定频率校验系数合理取值范围，并确定评定结构承载力的频率校验系数下限值，作为结构承载力动力评定的准则。(4)从阻尼耗散能量的角度进行分析，由能量守恒原理推导桥梁结构材料阻尼与结构刚度之间关系，分析桥梁结构病害对结构阻尼的影响。以实测数据为样本，统计分析各种影响参数的敏感性，确定出完好桥梁阻尼合理范围，为阻尼指标评定结构承载力提供定量依据。(5)以三轴车辆为例建立装配式板桥车-桥耦合计算模型，分析单片主梁不同位置病害、空间结构不同位置主梁破损以及不同位置铰缝破损程度对装配式板桥冲击系数的影响，并通过样本桥梁实测结果验证了结构各种病害对冲击系数的影响规律。(6)对样本桥梁实测冲击系数进行统计分析，回归结构实测冲击系数与实测频率之间的关系，并与规范公式计算结果和理论计算结果进行比较，对现行规范冲击系数计算方法进行修正，为同类装配式板桥设计和承载力评定提供依据。建立冲击系数理论计算结果与实测结果之间的关系，通过比较实测值与理论计算预测值来评定结构受力状态。(7)建立桥梁结构承载力动力综合评定系统，以完好桥梁和承载力不足两类桥梁为例分别按静载评定方法和动载评定方法对其进行承载力评定，以静载评定结果验证结构动力评定系统的合理性。总结以上工作内容，文中主要有以下创新点：(1)以样本桥梁实测数据为依据研究装配式板桥受力特性通过对装配式板桥实测数据统计分析，得出了不同型式铰缝的受力特性、桥面铺装受力特点和护栏沿桥面横向分配原则以及护栏对结构承载力的贡献。以此为基础，对装配式板桥建立能够真实反映结构受力特点的有限元模型进行理论分析。(2)装配式板桥校验系数取值范围研究按不同类型装配式钢筋混凝土板桥的受力特点建立有限元模型，对其施加与荷载试验一致的载荷，理论计算结构挠度和应变，与相应的各桥实测数据进行对比，得到结构挠度和应变校验系数。结合各桥承载力检算结果，统计分析得出装配式板桥承载力满足要求时的挠度和应变校验系数合理取值范围。(3)频率校验系数评定结构承载力方法研究首次提出频率校验系数评定结构承载力方法。该方法通过建立动载频率校验系数与静载挠度校验系数和静载应变校验系数之间的关系，综合考虑挠度校验系数和应变校验系数的合理取值范围来确定频率校验系数的合理取值范围，并以结构频率校验系数为参数快速评定装配式板桥承载力。(4)装配式板桥阻尼评定方法研究理论上建立结构阻尼与结构刚度之间关系，通过阻尼的变化反映结构刚度变化，以此来判断结构损伤程度，结合样本桥梁实测数据统计分析，确定钢筋混凝土桥梁阻尼合理取值范围，为此类桥梁阻尼指标评定结构承载力提供依据。(5)板桥车-桥耦合振动程序研究以三轴车辆为例建立车-桥耦合振动方程，采用分离迭代法，编制了板桥车-桥耦合振动程序，并以实例验证了其计算结果的正确性，为装配式板桥动力响应分析提供计算平台。(6)装配式板桥承载力动力综合评定系统研究建立装配式板桥动力综合评定系统，首次采用桥梁结构频率、阻尼比和冲击系数三者作为指标共同评定桥梁结构承载力。更多还原

【Abstract】 The dynamic assessment method of bridge’s bearing capacity is always the researchhotspot in the academic field.In the past,The dynamic assessment research was focused onbuilding the connection between single beam’s stiffness and frequency by regressing theexperiment data obtained in lab.By far,there is no well-rounded theory that can be used inpractice because of the test data’s discretization.Though the span of plate bridge is usuallysmall,the task of static test is complicated,it is economical and essential to look after a fastevaluation method for assessing structure’s load bearing capacity.Based on this,189 bridgesin the actual projects as a sample were selected,the connection between static test result anddanymic test result was built in this paper in order to assess the structure’s bearing capacity bydynamic characteristics of bridge.The main contents are as followings:(1)On the base of actual observation records of bridge samples,the mechanicalproperties of the assembly slab bridge is obtained,and the mechanical characteristic ofhinged joint and bridge deck,the distribution of the guard rail in transverse direction are alsodiscussed.Based on the above analysis,the rational theoretical model is built,which offerssome reference to assess the structure’s bearing capacity.(2)The dynamic characteristic of assembly slab bridge is discussed,which is brought byanalyzing of different diseases location,disease patterns and structural parameters.Thetheoretical results are validated by the actual test data,which is as a foundation for assessingthe structure’s bearing capacity.(3)After analyzing the relationship between the deflection,frequency and stiffness ofstructure,the concept of nominal frequency coefficient is put forward.Besides,therelationship between static deflection and strain coefficient and dynamic strain coefficient isobtained,furthermore,using static load test data for the analysis of sample return,therelationship between of deflection and strain coefficient and frequency coefficient is also builtup.Meantime the rational range of deflection coefficient,strain coefficient is obtained byverifying the structure’s bearing capacity,and the rational range of frequency verificationcoefficient is obtained on the foundation.The lower acceptance value is confirmed as the reference to assess the structure’s bearing capacity.(4)Carrying on the analysis from the damping diffusion energy angle,the influence ofstructure’s disease to damping is studied,which is after deriving the relational expressionbetween damping and stiffness.In addition,the rational range of damping is confirmed basedon analyzing the actual observation records,which is a reliable reference for assessing thestructure’s bearing capacity.(5)The vehicle-bridge coupled model is built on the base of three axis vehicle in orderto research the influence of the disease in the different location in single beam,the disease indifferent beams,and the disease of hinge and this regularity is validated by the actual testresult.(6)The relations between impact coefficient and frequency are regressed based on the testdata.The standard formula is updated after comparing the theory result and the regress result,which is a rational reference for designing and assessing the same type bridge.Furthermorethe relations between theory result and actual observation result are concluded,which can beused for assessing the structure’s mechanical characteristic.(7)The general dynamical evaluation system of structure’s bearing capacity is broughtforward,which is validated by different strengthened bridges on the base of comparingdead-load test result and live-load test result.The following innovations of this paper are summed up based on above labors:(1)Study on the mechanical characteristic of the assembly slab bridge based onthe test dataThe mechanical characteristic of hinged joint and bridge deck,and the distribution of theguard rail in transverse direction are derived after analyzing the actual test value.With thisconclusion,the rational theory model is built to provide references for assessing thestructure’s bearing capacity.(2)Study on rational span of verification coefficientThe deflection and strain of structure is received on the respective model with the sameload as the experimentation load,and deflection and strain verification coefficient is built upafter comparing the actual measured value.The rational span of deflection/strain verificationcoefficient is discussed based the structure’s load bearing capacity. (3)Frequency coefficient evaluation method of structure’s bearing capacityFor the first time,evaluation method of frequency coefficient is built up to evaluated thebridge’s bearing capacity.The method is implemented by the span of frequency coefficient,which is ascertained through the relation between frequency coefficient and deflection andstrain coefficient.(4)Study on damping evaluation method of structure’s bearing capacityThe expression between damping and stiffness is established,and the damaged degree ofstructure is assessed by the stiffness changes which are reflected by damping.The rationalspan of damping is gained after analyzing the actual observation records,which is thereference for assessing the structure’s bearing capacity.(5)Study on vehicle-bridge coupled vibration program of multi-beams bridgeThe vehicle-bridge coupled vibration equation is detruded on the base of three axisvehicle,and the vehicle-bridge coupled vibration program is established with iteration method,which is used for analyzing the dynamic response of the assembly slab bridge.(6)Dynamic evaluation system of structure’s bearing capacityFor the first time,the dynamic evaluation system is built up to assess structure’s bearingcapacity with structure’s frequency,damping and compact coefficient.更多还原