摘要
混凝土结构耐久性设计中的一个重要方法就是概率极限状态设计法,这种方法根据描述耐久性劣化过程的数学模型,首先建立耐久性极限状态方程,再将环境作用与抗力作用的某个特征值与相应的分项系数代入极限状态方程,经验算就可在一定可靠度水准上得到耐久性设计参数的设计值。选用合适的设计参数是混凝土结构耐久性设计的关键问题,设计参数应具有明确的物理意义和容易掌握的统计规律,且易为设计人员所接受。根据理论与经验相结合的碳化深度模型,建立了考虑保护层厚度与混凝土强度两个随机变量的碳化耐久性的分项系数设计方法,提出了碳化寿命准则极限状态的目标可靠指标的建议值,计算确定了保护层厚度与混凝土抗压强度满足目标可靠指标的分项系数,由此给出了碳化寿命准则的耐久性设计表达式。该耐久性分项系数设计法适用于一般大气环境下任意设计使用年限的不允许出现钢筋锈蚀的混凝土结构,根据设计表达式可直接确定满足耐久性要求的保护层厚度与混凝土强度。
An essential method for durability design of concrete structures is the probability-based limit states method.The limit state function of durability is established first based on the model which describes the deterioration process,and then the characteristic values of concerned random variables and partial factors are determined.Hence,the design values of durability indexes can be determined which ensure the structures achieve an acceptable reliability with respect to the considered limit states.One of the key issues in process of durability designing depends on selecting the optimal design parameters.The parameters should be chosen based taking into account their physical meanings,reception level by the designers and the statistical regularity involved.The design methodology proposed is based on reliability theory traditionally used in the structural design and with the aid of a theoretical & empirical combined model which describes the development of carbonation of concrete.The suggested values of target reliability index describing the acceptance probability of carbonation depth are proposed.The partial factors which are able to satisfy the requirement of target reliability index are evaluated.The purpose of the design rules is to ensure that the concrete structures that corrosion of reinforcement are not allowed will achieve the required service life under the common atmospheric environment condition.The different sets of concrete cover thickness and concrete strength which can satisfy the durability requirements.
出处
《建筑结构学报》
EI
CAS
CSCD
北大核心
2008年第S1期42-46,共5页
Journal of Building Structures
基金
国家自然科学基金重点资助项目(50538060)
国家自然科学基金资助项目(50678143)
关键词
耐久性设计
碳化
分项系数
可靠指标
混凝土结构
durability design
carbonation
partial factor
reliability index
reinforced concrete structure
