| Concrete structures durability design which provided by existing norms pay muchemphasis on the qualitative conceptual design. As the reliability under differentenvironmental standards implicit role is different, we can not quantitatively assess thelife of concrete structures. Currently the concrete structures durability design andevaluation methods which based on probability is lack of enough flexibility, generality,and precision of reliability control is low, so it should not be used to guide the design ofconcrete structures durability.For the shortcomings of the current concrete structures durability design methods,references to widely used material deterioration of performa nce prediction model andthe basic idea of international standard design value method, based on the currentstructure reliability theory, according to the structure function in any state, established acommon approach of concrete structures durability probability design in generalatmosphere. This paper proposed concrete structures durability probability designgeneral expression by three limit state of concrete structures material propertiesdegradation, they are based on the life of carbonation criteria, based on the life of rustcracking criterion, and based on the life of the crack width criteria. According to thereliable indicator of JC method, established expressions between design values of basicvariables and probabilistic characteristics and objective reliable indicators. The designvalue of the basic variables expressed as the product form of basic variables referencedesign value and partial factor, unity to the partial factor method. In order to improvedesign accuracy, in the design of concrete structures durability, the refined materialperformance degradation process is divided into three stages based on limit state. The sensitivity coefficient values of reliability control accuracy determined by the optimalway of control reliability. That is all the basic variables set only one master volume, andmaster volume is determined using the enumeration method.Compared with the current method of concrete structures durability design, thegeneral method for probabilistic durability design of conc rete structures are flexible,general-purpose, high precision and practicability, allowing owners to choose a differenttarget reliability index, and to introduce the latest statistics. The general method forprobabilistic durability design of concrete structures can be used in special occasions,such as the occasion that have special occasions of target reliable indicator, the occasionthat have greater access between basic variables probabilistic characteristics andconditions of norms, or durability assess the existing concrete structures which variationcoefficient of some variables changed greatly. |
