【作者】 杨磊；

【导师】 田仲初；

【作者基本信息】 长沙理工大学 ， 桥梁与隧道工程， 2012， 硕士

【摘要】 近年来，随着桥梁建设的飞速发展，桥梁工程风险评估研究正在越来越被工程界所重视，交通运输部也陆续颁布了不少规范制度来指导桥梁风险评估工作。目前，桥梁工程的风险评估根据规范要求，一般仅限于对大跨度、高墩、工艺复杂或者特殊结构的桥梁进行风险评估，而对于中小跨径的桥梁却并没有做出要求。但是，采用特殊施工方法或是桥梁结构复杂的某些中小跨径桥梁由于其自身施工特点、难点，也会导致施工中风险的产生。因此根据桥梁施工实际情况，也需要对此类桥梁进行风险评估。本文背景工程长沙市营盘东路浏阳河大桥，虽然跨径远远没有达到风险评估要求，但由于其大坡度斜连续梁顶推特点，比一般顶推施工面临更大的风险，因此也要对其进行风险评估。本文首先论述了桥梁施工风险及风险评估的相关理论知识；接着对当前桥梁工程风险评估领域常用到的分析方法及其特点进行了简述；最后通过详细识别营盘东路浏阳河大桥主桥混凝土箱梁顶推运行阶段各分项工程项目中的风险因素，利用风险模型计算得到整个顶推施工阶段的总体风险，并据此提出相应的预防控制措施。首先，从箱梁在顶推运行阶段可能会出现的问题出发，对顶推阶段涉及到的各方面及其整体对工程质量、企业声誉、企业经济等方面有重要影响的风险因素，进行全面识别，并将这些复杂因素分解成较为简单的基础单元。其次，利用有限元模型对顶推各个工况中的关键结构进行仿真计算，通过对比、判断所得计算结果，找出顶推最不利工况及结构最薄弱环节，由此识别出顶推运行阶段识别施工中可能遇到的风险。根据对风险进行识别后得出的结果，利用层次分析法建立层次模型和风险评价指标体系。本文采用专家调查法、层次分析法与模糊数学理论相结合的方法，以风险自身定义为基础对指标进行量化，最终得到顶推运行阶段的总体风险，该种方法相较于单一的计算方法能够更好的量化指标。最后，根据得出的风险评估结果提出相应风险的防范控制措施，保证顶推施工顺利进行。对识别出的风险进行预防和控制，为以后类似混凝土箱梁顶推施工工程安全顺利实施提供参考。更多还原

【Abstract】 In recent years, the risk assessment research of bridge engineering is more and morevalued by the engineering circles with the rapid development of bridge construction.The Ministry of transport has also successively promulgated many standard system toguide bridge risk assessment. At present, based on the standard requirement, the riskassessment of bridge engineering is generally confined to the large span, high pier,complicated technology or special structure bridges, but it makes no demands on thesmall or medium span bridges. However, some small or medium span bridges whichused some special construction methods or complex structure can also cause risks bythe construction characteristics and difficulties. According to actual situation of bridgeconstruction, it is necessary to conduct risk assessment for this kind of bridge. LiuyangRiver Bridges of Yingpan road in Changsha city as the engineering background in thispaper is not far from meeting the requirements of risk assessment, but it has thecharacteristics of large slope skewed continuous beam bridge launching construction,which is faced with greater risks than the general launching construction assessment,so it needs to proceed with risk assessment. In this paper, firstly the relevanttheoretical knowledge of risk and risk assessment is discussed; secondly a relativelydetailed introduction about the analysis methods and the characteristics of currentproject risk assessment is provided; finally by comprehensively identifying the riskfactors of each subentry construction project in the progress of launching constructionand using a risk model to calculate the overall risks of the whole launchingconstruction, the corresponding prevention and controlling methods are offered.First of all, starting from the appearing problems during the operation of box girderlaunching, comprehensive identification which is for important risk factors of projectquality, enterprise reputation, and corporate economy which related with launchingconstruction is identified comprehensively, and then these complex factors areseparated into relatively simple basic units.Secondly, using the finite element model to have a simulated calculation for eachlaunching construction in the various operating conditions, judging and analyzing thecalculation which is in order to find the most unfavorable launching construction andthe weakest region of structures, then identifying possible risks of construction.According to the conclusions of the risk identification, a hierarchical model and risk assessment system is established by analytic hierarchy process. The evaluation methodused in this article is the professional investigation method combined the analytichierarchy process and fuzzy mathematical theory together, and quantify the risk whichare defined as indicators and finally acquire the overall risk of launching construction.This method is different from the past single method which can quantify indexeffectively.Finally, based on the risk assessment results, the corresponding risk controllingmeasures are proceed well to ensure the jacking construction carried out smoothly,simultaneously providing good references in order to identify risks and to providetheory and measures for the safe implementation of the future similar concrete boxgirder launching construction.更多还原