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1、Abstract Abstract The total number of highway bridges in china is more than 650000 which is the most of the world at present. The proportion of concrete girder bridge is about 74%. According to statistics, the proportion is 42% which age is more than 10 years in the national, provincial, prefectural
2、 highway and 25% which age is more than 20 years. The diseases concentrated exposure period of the domestic short and medium span bridge is 1520 years and long-span bridge is 68 years. Therefore, there will be more and more highway bridge appearing the problems about durability and bearing capacity.
3、 Highway construction will gradually focus on maintenance, repair and strengthening from construction to ensure highway construction career sustainable development. Accurate assessment of the state of existing bridge is the foundation and basis of maintenance and reinforcement. The detection and mai
4、ntenance commonly carried out after the bridges have obvious problem because methods to assess bridge state at present were time-consuming which would lead to higher cost of maintenance and reinforcement. Vehicle impact load is the main load form of highway bridge. At present the evaluation of bridg
5、e is main focus on technical condition and bearing capacity, rarely on dynamic performance which results are not comprehensive. Bridge dynamic testing has the following advantages: small amount of work , short test time and can reappear the real operation state. Thus, choosing the concrete girder br
6、idge which has wide distribution to research the dynamic evaluation technique and search the bearing capacity and dynamic performance evaluation method based on dynamic testing would avoid the disadvantages of traditional methods and provide a way to rapid、accurate evaluate of the actual working con
7、dition of the bridge. At present, the dynamic load tests assessment system of bridge has not yet mature.This paper focus on how to build a dynamic assessment system of highway concrete bridge and study the problem related to testing, analysis and evaluation which involved in the system. The main res
8、earch contents and results are as follows: Firstly, vehicle field tests including moving vehicle and jumping vehilcle were identified as the reasonable exciting way in the test of dynamic characteristics through the comparation and analysis of the conventional methods. The characteristics of free vi
9、bration response are analyzed and the FFT+FT method were used to identify the dynamic characteristics based on free vibration responses. This paper give the process to test and identify the dynamic characteristics and example of engineering application. It would provide foundation for dynamic charac
10、teristics - III - 哈尔滨工业大学工学博士学位论文 evaluation of girder bridge. Secondly, the paper analysed the relation of dynamic and static stiffness of simple-supported girder under the influence of elastic support、rotational restraint、 axial force and open cracks based on the euler-bernoulli beam. RC rectangul
11、ar beam load tests were carried out to research the change of the dynamic stiffness、static stiffnrss and damp ratio. There was finite element analysis of continuous beam to study the influence in the dynamic and static stiffness of the joints, axial force and partial damage. The study above provided
12、 theoretical basis for using the static evaluation index to established the dynamic evaluation index. The regression analysis of the measured data collected verified the above analysis conclusion and get the regression formula between dynamic and static stiffness. First order vertical bending freque
13、ncy testing coefficient to evaluate bridge carrying capacity established Using the static deflection testing coefficient range in the specification. Dissipating energy evaluation index and corresponding evaluation grade were put forward to evaluate the speed of dissipating vibration energy using fre
14、quency and damping ratio based on the normal spacing of the moving vehicles in highway. Thirdly, frequency distribution of dynamic response of simple-surpported gider bridge under moving vehicle(simplified as a constant force and harmonic force) were analyzed theoretically. Methods to realize separa
15、ting the dynamic and static composition in dynamic response by frequency domain low-pass filter were put forword. Frequency distribution of dynamic response of continuous gider bridge under moving vehicle were analyzed by FEM. separation methods of separation in simple-surpported gider bridge were e
16、xtend to continuous gider bridge. There were introduction of separation methods application in impact factor calculation、 amplitude extraction and bearing capacity quickly evaluation combined with the engineering practice. Then, there were reseach on vehicle-bridge coupling vibration analysis method
17、s to provide means for the following calculation. The dynamic response with statistical significance of conventional highway girder bridges through the method of probability distribution. The reasonable limits of vertical acceleration, amplitude and impact factor were discussed to assess the dynamic
18、 performance of girder bridge. Finally, the evaluation contents mainly aimed at the applicability of the bridge which includes the bearing capacity and dynamic performance. The comprehensive dynamic evaluation system based on dynamic loading test for the concrete girder bridge was put forward. The p
19、aper aslo introduced the flow chart of the comprehensive evaluation system and examples of engineering application. Based on the above analysis results, the simple and practical methods for girder - IV - Abstract bridge dynamic characteristics test、estimation and evaluation wrer proposed. The separa
20、tion method of the dynamic deflection was put foword. The reasonable limits of the dynamic response were got. The work performance evaluation methods based on dynamic testing for the highway girder bridge were established finally, which can be used to evaluate the serviceability limit state bearing
21、capacity and dynamic performance quickly and reasonably. Keywords: concrete girder bridge; dynamic testing; performance evaluation; serviceability limit state bearing capacity; dynamic response - V - 哈尔滨工业大学工学博士学位论文 目 录 摘 要. I ABSTRACT III 第 1 章 绪 论 .1 1.1 课题背景及研究的目的和意义 1 1.2 公路桥梁常用评定方法与分析 3 1.2.1 基
22、于外观调查的方法.3 1.2.2 基于设计规范的评定方法 .3 1.2.3 荷载试验法 4 1.2.4 专家系统评价法.5 1.2.5 公路桥梁常用评定方法总结 .5 1.3 桥梁动力评定方法研究现状与分析 .6 1.3.1 桥梁动力评定方法研究现状 .6 1.3.2 桥梁动力评定方法分析.8 1.3.3 动测参数评价方法相关问题探讨 .9 1.4 本文的主要研究内容 .10 第 2 章 梁式桥动力特性合理测试及估计方法研究 12 2.1 引言 12 2.2 桥梁激振方法分析.12 2.3 基于自由衰减响应的动力特性估计方法15 2.3.1 自由衰减振动响应特性分析 .15 2.3.2 频率和
23、相位 18 2.3.3 阻尼比 26 2.3.4 振型 33 2.4 动力特性测试估计方法及工程实例36 2.4.1 测试估计方法.36 2.4.2 工程实例 38 2.5 本章小结 .39 第 3 章 梁式桥动力特性评定方法研究41 3.1 引言 41 3.2 简支梁刚度影响因素分析及对比 .42 - VI - 目 录 3.2.1 分析指标的引入42 3.2.2 支座弹性支撑44 3.2.3 转动约束 .46 3.2.4 轴向力 .49 3.2.5 裂缝 .53 3.2.6 分析结果汇总63 3.3 连续梁刚度影响因素分析及对比.63 3.4 自振频率评价方法 .69 3.5 阻尼比评价方法
24、.73 3.6 本章小结 .75 第 4 章 梁式桥动挠度响应动静分离技术及应用 76 4.1 引言 76 4.2 移动车辆作用下简支梁桥振动响应分析及分离 .77 4.2.1 匀速移动常量力77 4.2.2 匀速移动简谐力81 4.2.3 公路简支梁桥挠度响应分析 .82 4.2.4 动响应动静分离方法85 4.3 移动车辆作用下连续梁桥挠度响应分析及分离 .89 4.3.1 等跨径连续梁89 4.3.2 不等跨径连续梁93 4.4 动静分离的应用及工程实例 99 4.4.1 动静分离的应用100 4.4.2 工程实例 .101 4.5 本章小结 .105 第 5 章 梁式桥动力响应评价方法
25、研究107 5.1 引言 107 5.2 车-桥耦合振动分析方法 107 5.2.1 车辆振动方程108 5.2.2 桥梁振动方程109 5.2.3 桥面不平整度模拟110 5.2.4 车-桥耦合关系分析 112 5.2.5 车-桥系统耦合振动方程求解.113 5.3 中小跨径桥梁车-桥耦合振动响应分析.113 5.3.1 车辆分析样本.115 - VII - 哈尔滨工业大学工学博士学位论文 5.3.2 基于概率分布的振动响应取值方法 .116 5.3.3 跨数的影响 120 5.3.4 常规中小跨径桥梁计算与分析 .123 5.4 公路梁桥动力响应评价指标.130 5.4.1 竖向加速度 1
26、30 5.4.2 竖向振幅 132 5.4.3 冲击系数 134 5.5 本章小结137 第 6 章 梁式桥动力综合评定方法与工程应用 138 6.1 引言 138 6.2 动力综合评定方法.139 6.2.1 桥梁调查及计算.139 6.2.2 动载试验 139 6.2.3 测试结果评定方法.140 6.2.4 综合评定流程.141 6.3 工程应用 .143 6.3.1 简支梁桥 143 6.3.2 简支转连续梁桥.146 6.3.3 大跨径变截面连续梁桥.148 6.4 本章小结 .149 结 论.150 参考文献.152 附 录.161 攻读博士学位期间发表的论文及其它成果 167 哈
27、尔滨工业大学学位论文原创性声明169 哈尔滨工业大学学位论文使用授权书169 致 谢.171 个人简历.172 - VIII - Contents Contents Abstract (In Chinese) I Abstract (In English) III Chapter 1 Introduction. 1 1.1 Background, objective and significance of the subject 1 1.2 The basic evaluation methods of highway bridge and analysis 3 1.2.1 Method ba
28、sed on the experience of real bridge detection 3 1.2.2 Method based on the design code. 3 1.2.3 Method based on load test 4 1.2.4 Expert system evaluation method. 5 1.2.5 Summary of the basic evaluation methods. 5 1.3 Research state and analysis of dynamic evaluation method for the bridge . 6 1.3.1
29、Research state of dynamic evaluation method for the bridge. 6 1.3.2 Analysis of dynamic evaluation method for the bridge 8 1.3.3 Discussed on the problems related to the evaluation methods based on dynamic parameters. 9 1.4 Main research contents of this subject 10 Chapter 2 Research on the reasonab
30、le testing and identification method for dynamic characteristics of girder bridge 12 2.1 Introduction 12 2.2 Analysis of the exciting method. 12 2.3 The modal parameters estimation method based on free attenuation response 15 2.3.1 Analysis of the characteristics of free attenuation response. 15 2.3
31、.2 Frequency and phase 18 2.3.3 The damping ratio 26 2.3.4 Vibration mode. 33 2.4 Dynamic characteristics test process and engineering examples 36 2.4.1 Test process 36 2.4.2 Engineering examples 37 2.5 Brief summary . 39 Chapter 3 Research on the evaluation method for dynamic characteristics of gir
32、der bridge . 41 3.1 Introduction 41 3.2 The influence factors and comparison of stiffness of simple-surpported girder. 42 3.2.1 The evaluation index 42 - IX - 哈尔滨工业大学工学博士学位论文 3.2.2 Elastic support 44 3.2.3 Rotational restraint. 47 3.2.4 Axial force . 49 3.2.5 cracks. 53 3.2.6 Summary of the analysis
33、 results 63 3.3 The effect factors and comparation of stiffness of continuous girder. 63 3.4 The frequency evaluation method of girder bridge 69 3.5 The damping ratio evaluation method of girder bridge 73 3.6 Brief summary . 75 Chapter 4 Dynamic deflection component separation technology and applica
34、tion of girder bridge . 76 4.1 Introduction 76 4.2 Vibration composition analysis and separation of simple-surported beam under moving force. 77 4.2.1 Moving constant force 77 4.2.2 Moving harmonic force 81 4.2.3 The dynimac deflection analysis of simple-supported girder bridge 82 4.2.4 The dynamic
35、response separation method 85 4.3 Vibration composition analysis and separation of continuous girder bridge under moving vehicle 89 4.3.1 Equal cross continuous girder bridge. 89 4.3.2 Unequal cross continuous girder bridge. 93 4.4 The application of Dynamic response component separation and enginee
36、ring example. 99 4.4.1 Application100 4.4.2 Engineering example.101 4.5 Brief summary 105 Chapter 5 Research on dynamic responses evaluation method of girder bridge107 5.1 Introduction.107 5.2 The vehicle-bridge coupling vibration analysis method107 5.2.1 Vehicle vibration equation.108 5.2.2 Bridge
37、vibration equation109 5.2.3 Bridge deck flatness simulation 110 5.2.4 The vehicle-bridge coupling relation 112 5.2.5 The solution of vehicle-bridge coupling vibration equation113 - X - Contents 5.3 The vehicle-bridge coupling vibration analysis of small and medium span girder bridge 113 5.3.1 Select
38、ed vehicle sample 115 5.3.2 Vehicle-bridge coupling vibration response calculation based on the probability distribution.116 5.3.3 The influence of different number of across .120 5.3.4 Vehicle-bridge coupling vibration calculation and analysis of small and medium span girder bridge.123 5.4 Highway
39、bridge dynamic responses evaluation index analysis.130 5.4.1 Vertical acceleration130 5.4.2 Vertical amplitude .132 5.4.3 Impact factor.134 5.5 Brief summary 137 Chapter 6 Dynamic comprehensive evaluation methods of girder bridge and engineering application .138 6.1 Introduction.138 6.2 Evaluation p
40、rocess 139 6.2.1 Bridge survey and calculation.139 6.2.2 Dynamic load test139 6.2.3 Test results assessment140 6.2.4 Comprehensive evaluation precess141 6.3 Engineering example.143 6.3.1 Simple-surpported girder bridge .143 6.3.2 Equal cross continuous girder bridge146 6.3.3 Unequal cross continuous
41、 girder bridge148 6.4 Brief summary 149 Conclusions 150 References 152 Appendix 161 Papers published in the period of Ph.D. education .167 Statement of copyright 169 Letter of authorization 169 Acknowledgements 170 Resume .171 - XI - 第 1 章 绪 论 第 1 章 绪 论 1.1 课题背景及研究的目的和意义 改革开放 30 多年来，我国桥梁建设取得了巨大的发展，目
42、前我国公路桥 梁总数已超过 65 万座（混凝土梁式桥约占 74%） ，成为世界第一桥梁大国。 据不完全统计，国省县道上的桥梁有 42%的桥龄超过 10 年，有 25%的桥龄超 过 20 年。发达国家公路桥梁病害集中暴露期一般在 2030 年左右，而国内公 路桥梁由于维修养护不到位、超载现象屡禁不止的原因，病害集中暴露期普遍 小于发达国家，中小跨径桥梁一般在 1520 年，大跨径桥梁在 68 年。因此， 将会有越来越多的公路桥梁出现耐久性降低和承载力不足等问题。 根据交通运输部统计，截止到 2007 年，我国危桥座数为 98623 座，共计 3068704 延米，危桥占全部桥梁的比例按座数为 1
43、7.30%，按延米数为 13.23%， 且有相当数量的桥梁按公路桥涵养护规范 （2004）评定技术等级为三、四 类桥，存在较大的安全隐患。在长期超载或者不可预测的外力作用下，这些危 桥以及存在安全隐患的桥梁，很容易发生严重的事故。近年来，国内桥梁坍塌 事故接连发生，造成较大的经济和社会影响（图 1-1） 。 2007 年 10 月 23 日2004 年 6 月 10 日 盘锦市田庄台大桥突然发生垮塌 包头市民族东路高架桥发生倾斜 2011 年 7 月 15 日2010 年 6 月 8 日 吉林抚松锦江大桥突然垮塌 杭州钱江三桥引桥部分桥面突然塌落 图 1-1 近年国内桥梁坍塌典型事故 Fig.
44、1-1 Domestic typical bridge collapse accidents in recent years - 1 - 哈尔滨工业大学工学博士学位论文 根据我国公路桥梁的技术现状，为了保证我国公路建设事业的可持续发 展，公路建设的重点将逐步由建设转向养护、维修和加固，而桥梁的合理评估 是这一工作的前提。 目前我国公路桥梁状态评定主要依据的法规有 公路桥涵养护规范（JTG H11-2004） 、 公路桥梁技术状况评定标准 （JTG/T H21-2011）和公路桥梁 承载能力检测评定规程 （JTG/T J21-2011） 。以上法规主要根据桥梁表观质量 状况对桥梁技术状况进行评定
45、，或桥梁调查结合检算进行的承载能力鉴定。以 上方法都是根据对大量桥梁的试验检测结果统计分类而制定出系统的损伤程 度和评分标准， 然后根据检测人员凭借工程经验对既有桥梁的各项状况进行评 分，进行桥梁技术状况评定或者分析得到旧桥检算系数Z1，根据桥梁的相关资 料，通过检算得到桥梁的现有承载能力。这种评价方法的准确程度主要依赖于 桥梁破损程度分类和评分标准的细化、 准确程度以及检测人员的经验和技术水 平。 公路桥梁承载能力检测评定规程 （JTG/T J21-2011）规定，当桥梁调查 和检算不能确定桥梁的承载力时，应进行荷载试验。荷载试验分为静载试验和 动载试验。静载试验通过对桥梁施加与实际荷载相当
46、的等效荷载，测量控制截 面的变形、应变以及观察裂缝的发展情况，将测试结果与理论计算值和规范限 值比较，得到旧桥检算系数Z2，代替Z1综合评定既有桥梁的承载能力状态。桥 梁静载试验能较为准确的评价桥梁结构的承载能力， 但其测试时间长、 费用高、 风险大、容易导致桥梁发生新的损伤且影响交通，不适合大规模地对桥梁结构 进行检测。 从上述国内现行公路桥梁评定法规可以看出， 目前桥梁评定主要是针对桥 梁的技术状况以及承载能力，集中在静力层面上。应该指出的是，承载能力评 定中的正常使用极限状态是相对准确的， 而承载能力极限状态的评定则相对粗 糙。桥梁的技术状况评价主要依靠外观检查，工作相对简单，是桥梁养护
47、的基 本内容，也是桥梁管理部门必不可少的工作。而基于检算或者荷载试验的承载 能力评定手段、方法均费时费力，对于桥梁的检测、维修一般都是在桥梁出现 明显问题之后才进行。而此时的结构往往已积累了较大的损伤，承载能力下降 明显，不能做到防患于未然，导致维修加固费用较高。 公路桥梁在移动车辆荷载的作用下会发生振动，若振动过大，容易引起桥 梁结构的动力损伤及车内司乘人员的不适感。 尽管在常规的荷载试验中也进行 动载试验，但动载试验处于辅助地位；由于动力测试结果缺乏评价指标，一般 只对冲击系数进行评价，导致测试数据的浪费。 公路桥梁的动力测试相对简单， 反映了桥梁的真实工作状态， 且具有简便、 - 2 -
48、 第 1 章 绪 论 快速、无损等优点。本文将结合我国公路桥梁的具体情况，选择国内公路桥梁 中分布较广的梁式桥开展基于动力测试的评估方法研究和实践， 并试图解决以 下问题： 利用快捷简便的动力测试方法对桥梁正常使用极限状态承载能力进行 评定；提出合理的桥梁动力工作性能评价指标以及方法。以上问题的解决将打 破桥梁承载能力常规评定方法的限制，达到安全、快速评估桥梁实际承载能力 的目的；同时在动力层面上对桥梁技术状况评定作有效补充，使桥梁的状态评 估更为合理。通过常规的桥梁检查以及快速的动力试验，快速摸清桥梁的实际 状况， 提出合理的养护、 维修措施， 尽量减少桥梁维修或甚至替换的高额费用。 这也是
49、论文研究的主要目的和现实意义所在。 1.2 公路桥梁常用评定方法与分析 目前国内外普遍采用的桥梁评定方法大致有以下几种： 基于外观调查的方 法、基于设计规范的评定方法、荷载试验法和专家系统评价方法等。 1.2.1 基于外观调查的方法 基于外观调查的方法是根据广泛的桥梁检测和试验结果，经过统计、分析 而制定出系统的桥梁各构件损伤分类以及评分标准。 由桥梁检测人员凭其工程 经验对既有桥梁进行检测评分， 并对各构件的损伤程度、 安全性进行综合评价。 检测时主要依靠检测人员目测，在对桥梁状况有大致了解之后，再采用各种仪 器和技术手段，对局部缺陷、损伤进行精细化的检测。 该方法的准确程度主要取决于以下两方面： （1）规定的损伤程度分类和评 分标准的精细化程度和准确程度； （2）检测人员的检测经验和判断能力。由于 每座桥都有其特殊性， 现行评定规程中桥梁损伤程度的分类和评价等级标准并 不够精细。因此该方法主要依赖于检测人员的感性认知和定性的经验分析，人 为因素较多，导致评定结果相对粗糙，具有较大的主观性。 基于外观调查的方法简单易行， 检测结果依赖于桥梁损伤表象给检测人员 感官以及心理上的感受， 较适用于评价构造简单、 受力明确且易于观察的构件， 比如栏杆、伸缩缝、支座等。而对于受力复杂且缺损较为严重的构件，仅靠表 观现象凭借