【作者】 胡琦忠；

【导师】 金伟良；

【作者基本信息】 浙江大学 ， 结构工程， 2009， 博士

【摘要】 工程结构领域的投资一般较高,资源消耗相对较大,为了完善可持续发展的目标,提高工程结构建设项目投资的经济回报率,有效地节约资源,尽量规避及减少各类风险,有目的地避免短期行为,转而获取长远的利益,亟需在工程技术领域从工程结构的整体出发,立足全局性的理念,加强工程结构的全寿命周期理论及应用研究。因此,本文以保证工程结构的安全可靠、耐久适用及经济优化的有机统一为目的,建立了工程结构的全寿命周期研究基础框架,提出了基于核心指标的分析方法及其间的关系优化,研究了工程结构全寿命的设计及管理决策基础优化,形成了基于核心指标的工程结构全寿命周期研究。具体内容如下:1)从工程结构的方案选择、结构设计、施工、运营、老化及废除等的整个时间历程上定义了工程结构的全寿命概念,分析了各阶段的结构全寿命成本特点,从时间、概率及经济上提出了工程结构全寿命周期研究的内涵。2)依据从“目标—内容—方法”的基本研究思想,构建了工程结构全寿命周期研究的基础框架:建立了以质量可靠、时间优化及经济优化组成的核心目标为主,并考虑结构和谐、环保节能及可持续等主题的绿色目标的工程结构全寿命周期研究目标体系,并以核心目标为指导,确定了以结构的使用寿命时间指标、全寿命可靠性能指标及全寿命成本指标等三大核心指标为基础的工程结构全寿命周期研究基本内容。3)使用寿命指标是工程结构全寿命周期研究最主要的时间指标,起到了全局性的指导作用。分析了工程结构设计使用寿命的确定依据,并根据使用寿命的判别准则,建立了结构基于不同极限标准的剩余使用寿命概率预测模型。4)全寿命可靠性能指标是工程结构全寿命周期研究核心指标中的基础指标。通过结构可靠性的基本分析,依据作用效应及结构抗力的时变理论模型,并运用贝叶斯信息更新理论分析了使用荷载及实测信息对结构抗力的影响,以此建立了结构动态可靠度的分析模型,并定义了工程结构全寿命周期不同阶段的可靠度分析模型;通过结构的耐久性能指标阐述了结构性能等级的模糊划分方法及多级模糊综合评定方法,并建立了基于概率路径的结构耐久性能参数预测方法及马尔科夫链的结构耐久性能离散性预测方法。5)全寿命经济指标是工程结构全寿命周期研究核心指标中的决策指标。研究并建议了工程结构各项主要成本,即初建成本、检测成本、维护维修成本、失效成本(包括了直接成本、间接成本及功能性成本)、项目残值及效益等的预测模型,在此基础上根据结构的全寿命可靠性能变化,运用理论分析方法及事件树预测方法建立了工程结构全寿命成本的预测分析模型。6)在设计使用寿命确定的情况下,基于结构的性能因素及经济因素,建立了结构全寿命设计目标可靠指标的优化方法,并依据结构全寿命成本的预测及比较,优化了结构初始耐久性设计水平的选取方法;为提高结构全寿命设计的鲁棒性,建立了基于结构目标性能及成本的结构设计主要参数控制及管理方法。7)依托具体大型跨海桥梁的研究提出了其基础结构构件正常使用极限状态的全寿命设计目标可靠指标,并通过不同荷载引起的钢筋拉应力对混凝土裂缝宽度的贡献率不同建立了基于控制应力的可变荷载系数标定方法,最后,实例标定了具体大型跨海桥梁的可变荷载频遇值系数及准永久值系数,并实例分析了大型跨海桥梁主要设计参数的控制及管理。8)建立了工程结构全寿命的管理措施决策方法,优化了工程结构管理的目标可靠水平,确定了结构各项管理措施的实施准则,并通过全寿命成本的预测及比较优化了结构检测、维护及维修等措施的具体方案决策及时点决策。更多还原

【Abstract】 Construction of engineering structures usually demands relatively higher investment and more resource. In order to insist on a goal of sustainable development, to improve economic return, effectively to save resource, to reduce various risks and to obtain long-term benefits, it’s much necessary to carry on a life cycle research on engineering structures and its application with a global perspective. With the norm of structural safety, serviceability, durability and economical efficiency achieving an optimization, the fundamental frame of life cycle research on engineering structures is established, the research methods of the key indictors and their optimization are put forward and the basic optimization of life cycle design and management of engineering structures is studied. The content includes1) The concept of life cycle on engineering structures is defined by the whole life of engineering structures including planning, design, construction, operation, aging and decommissioning. The characteristic of structural life cycle cost in different stages is illustrated and the connotative meaning of life cycle research on engineering structures is studied with structural timing, probability and cost.2) The fundamental frame of the life cycle research on engineering structures is set up with the concept of research being from goals to content then to methodology. The key goals, which including performance optimization, timing optimization and economy optimization, and the green goals, which taking harmoniousness, environmental protection, energy saving and successiveness into account, constitute the goal system. According to the key goals the basic content of the life cycle research on engineering structures is proposed based on the three key indictors of structural service life, structural life cycle performance and structural life cycle cost.3) The indictor of structural service life, having a global effect of guidance, is the most important indictor of timing. The factors to determine the design reference life of a structure is analyzed and several prediction model of residual service life with probability is proposed with the norm of determining structural service life.4) The indictor of structural life cycle reliability performance is the fundamental indictor among the three key ones. The model of structural time-dependent reliability is established according to the models of time-dependent load effect and structural resistance updated by the service load and actual test information with the Bayesian method. The reliability models in different stages of engineering structures are also defined. In addition, the fuzzy partition and the fuzzy evaluation for the grades of structural durability performance are proposed, the corresponding prediction method is established with the Markov chain and the parameters of structural durability is also predicted based on a path probability method.5) The indictor of structural life cycle cost is the decision-making indictor among the three key ones. The prediction models of main cost including initial construction, inspection, maintenance, repair, failure, deficiency of functionality, decommissioning and income are proposed and the prediction model of structural life cycle cost for engineering structures is established based on theoretic analysis and event tree method according to change of structural life cycle reliability performance.6) Suppose the design reference life is determined, the method to optimize the target reliability index for structural life cycle design on engineering structure:; is proposed based on the structural performance and structural life cycle cost. The method to optimize the initial design of durability level is put forward according to the comparison of structural life cycle cost. And the method to control and manage the main parameters of structural design is established based on the target reliability and the correlative cost so as to increase robust of a structure.7) The target reliability index of the foundation structures of sea-crossing bridges on serviceability limit states is suggested and a new method of calibrating factors of live loads, which is based on the contributed ratio of tensile stresses of reinforcing bars produced by various loads to the maximum crack width of concrete, is proposed. The calibration of the reliability-based factors of the frequent value and the quasi-permanent value of live loads is conducted through an analysis of an actual sea-crossing bridge and its main design parameters are also controlled and managed.8) The decision-making method of life cycle management on engineering structures in service life is established. Within this method, the target reliability index of life cycle management for existing structures is obtained and the planning and the timing of decision-making for the actions of inspection, maintenance and repair are optimized based on the prediction and the comparison of structural life cycle cost according to the norm of various actions carrying out.更多还原