【作者】 林阳子；

【导师】 黄侨；

【作者基本信息】 哈尔滨工业大学 ， 桥梁与隧道工程， 2009， 博士

【摘要】 既有预应力混凝土桥梁的评价问题是目前国内外桥梁界急需研究的热点问题之一。随着大、中型预应力混凝土桥梁在运营过程中性能的逐渐老化,桥梁安全事故时而发生,既有桥梁的评价问题日趋引起世界各国政府的重视,并对此项研究给予了持续的高强度的资金支持。到目前为止,桥梁评价的研究取得了一定的成绩,但由于实际桥梁评价问题与设计相比要复杂得多,诸多关键技术问题没有得到解决。基于此背景,本文对目前国内外桥梁评价的研究和应用状况进行了系统的总结和评述,分析了各种评价方法的优点及不足之处,并针对存在的问题进行了思考;结合目前国内预应力检测技术的水平及检测试验数据,就既有大、中型预应力混凝土梁桥上部结构评价的若干问题展开研究,主要研究内容及创新性成果如下:1.建立基于安全性、适用性和耐久性评价的桥梁的综合性评价体系。将对预应力混凝土桥梁进行评价分解为对桥梁安全性、适用性和耐久性分别进行评价,分别建立独立的评价模型进行评价;并通过分析确定桥梁安全性、适用性和耐久性对于具体桥梁的重要程度,进而完成桥梁的综合性评价。这种间接分析法将复杂的直接评价分解为若干较为简单而清晰的过程,可提高评价工程师判断的准确性和可操作性,从而使评价结果更为细致且更符合桥梁的实际情况。2.建立预应力混凝土桥梁的评价指标体系。结合目前国内预应力检测技术的水平及检测试验数据,分析预应力混凝土桥梁评价相关的评价指标如预应力筋锈蚀和预应力筋有效预应力缺损等对结构造成的不利影响;同时基于理论分析对其他评价指标如横向连接破损及荷载疲劳因素对结构的影响进行研究。并在考虑各评价元素对桥梁安全性、适用性和耐久性的不同影响基础上,分别确定评价中各元素的初始权重值和评价指标分级标准,从而建立预应力混凝土桥梁评价的评价指标体系,为量化的评价提供基础。3.提出成套评价方法,主要包括基于不确定型层次分析法初始权重确定、基于关联度评价值确定及基于剥离变权法权重修正计算等。对评价中各元素初始权重值的确定进行了研究。根据桥梁专家填写的桥梁评价元素两两判断矩阵,采用不确定型AHP的最优传递矩阵法计算判断矩阵,确定各评价指标的初始权重以及桥梁安全性、适用性和耐久性对于具体桥梁的重要程度,该方法相对简便,计算准确度较高,对专家构造的判断矩阵的一致性依赖相对较小。考虑到影响桥梁的各评价指标的不确定性,构造了正态关联函数进行关联度计算分析,并将评价模型中各个元素评价指标对各个评价等级的关联度作为桥梁定量评价的基本参数。该方法与桥梁结构的特性较为符合,可更好的对桥梁进行定量的评价分析。对分项层及指标层元素进行评价时,由于其下属元素之间不一定完全相对独立,且损伤程度大的元素的状态更大程度表征了其上级元素的缺损状态。本文考虑各元素的缺损状态采用剥离法进行权重修正,损伤较严重的元素修正系数大,反之则小。通过在评价过程中考虑元素缺损状态的权重修正,可使桥梁评价结果更符合具体桥梁的实际状况。并在对项目层及以上层次评价时,采用关联度及结构评定标度或全桥结构技术状态评分共同表征桥梁的缺损状态,从而使评价结果与现行《公路桥涵养护规范》的评价方法相统一。4.评价方法验证。通过评价方法的敏感性分析,以及实际桥梁的计算检验,证明了本文提出评价方法的合理性和正确性。5.编制预应力混凝土桥梁评价系统。根据评价分析思路,采用VB语言编制预应力混凝土桥梁评价系统。通过该程序系统,可大大减少评价工程师的计算工作;并且由于友好的可视化评价界面,不要求评价工程师必须具备较高的数学基础。同时,程序计算结果与手算结果相吻合,证明了程序的正确性。更多还原

【Abstract】 At present, evaluation of the damaged prestressed concrete bridges is one of the focuses of domestic and overseas bridge structure research. Because the long and middle span prestressed concrete bridges get aged and damaged, bridge accidents related to safety happened continually, and governments of many countries have paid more and more heed to evaluation of the damaged bridges, and also supplied a large amount of fund continuously for the research. Till now, some achievements have been attained on this subject. But because bridge evluation is more complicated than designing problem, there are still many key problems unsolved. Based on this background, this thesis reviews the reseach and application situation at home and abroad systematacially, analysises the excellence and deficiency of each evaluation method, and considers problems existing in this domain. Some problems of bridge evaluation are researched, combining with the uptodate prestress inspect technology and the inspect test data in our country. The main reseach contents and innovative achievement go as follow:1. Based on the safety, applicability and durability evaluation , the comprehensive evaluation system of bridge is estabished.It is presented that the bridge evaluation can be decomposed and evaluated respectively for the safety, applicability and durability. Also each detailed evaluation model is estabished respectively. Then by analyzing and confirming the respective importance degree of the the safety, applicability and durability for the idiographic bridge, the goal of bridge comprehensive evaluation can be achieved. Such indirect method decomposes complicated direct evaluation method into several simpler and clearer processes. It improves the veracity and maneuverability for evaluation engineer, accordingly makes the evaluation results more detailed and better accord with the practice conditions of bridge.2. The evaluation indexes system for prestressed concrete bridges is estabished.Combining with the uptodate prestress inspect technology and the inspect test data in our country, particular attentions are paid on studys of the disadvantage effects of evaluation indexes for prestressed concrete bridges. And those proper indices include prestressed tendon corrosion conditions, effective prestress of tendon, and so on. Also, based on theory analysis, the disadvantage effects of evaluation indices, such as transverse connection and dynamic fatigue of load, are researched. Then initial weights and evaluation grades standards of elements are confirmed. Based on above research, the evaluation indexes system for prestressed concrete bridges is estabished and it provides the foundation for establishing quantificational evaluation.3. A complete set evaluation method is presented. It includes the identification of element weights by uncertain type of AHP method; the identification of evaluation value by relative degree; the weights amending calculation by stripping method.Particular attentions are paid on identification of element weights of the safety, applicability and durability evaluation. Firstly, the bridge experts fill in the compared judgment matrix, then the uncertain type of AHP and optimal transitive matrix method were applied to confirm evaluation indices weights and the respective importance degree of the safety, applicability and durability for a idiographic bridge. This method is comparatively simple also the calculation veracity is better, and it less dependes on the consistency of the judgment matrix established by evaluation expresses.Considering the uncertainties of the effecting elements in the bridge structures, a normal relative function is derived to calculate and analyze the relative degree, and it take the relative degrees between the evaluation index of element and the evaluation grades in the evaluation modle as the basic parameters for the quantitative evaluation of bridge. This method accorded with the bridge property and it provides a better quantificational evaluation.When evaluating for the elements in sub-item and index levels, the weights of elements in sub-item and index levels are amended by stripping method, according to the damage extent of each element. Because the elements in sub-item and index levels are not independent completely, or some of them do not exist, and the condition of the element, with more damage, characterizes the damage condition of its upper-level element to a greater extent. By adjusting the weights, it makes the evaluation result in accordance with the fact conditions of bridge better. When evaluating for the elements in item or upper levels, relative degree and structure evaluation scale or structural technology mark are applied to characterize the damage conditions of prestressed concrete girder bridges, so this method can evaluate the prestressed structure in detail, and the evaluation results agree with the Code for Maintenance of Highway Bridges and Culvers (JTG H11-2004).4. Evaluation method verification.Based on the sensitivity analysis and the evaluation caluclation in a practice bridge, it is proved that the rationality and feasibility of the evaluation method.5. Programming of evaluation system for prestressed concrete bridgeBased on the evaluation analysis reason, an evaluation system for prestressed concrete bridge is programmed by VB. By using this evaluation program, the caluculation work of evaluation engineers is reduced greatly. And because of the friendly visible evalution interfaces, the complicated maths foundation is not requested for the evaluation engineers.更多还原