鉄筋コンクリート造建築物における鉄筋のかぶり厚さの信頼性設計手法の提案 : コンクリートの中性化によって鉄筋が腐食する場合

抄録

A calculating method of the cover thickness for reinforcement required for providing durability to reinforced concrete structures was studied based on the concept of the reliability engineering. The main results are summarized as follows. 1) The corrosion probability of reinforcement (P), caused by carbnation, is calculated using the average value (Ct) and coefficient of variation (v) of the carbonation depth of concrete, and the average value (D) and standard deviation (σ) of cover thickness for reinforcement. This is due to the test results that the scatter of the carbonation depth of concrete and the cover thickness for reinforcement is approximated by the normal distribution. 2) Using this corrosion probability of reinforcement, a failure condition of a reinforced concrete structure can be quantitatively defined. 3) The design thickness of the concrete cover (Dd) required for providing durability can be determined with the expected service life (T), the environmental condition (α), the finishing material (β), the water-cement ratio of concrete (x), the coefficient of variation of the carbonation depth of concrete (v), the standard deviation of the cover thickness for reinforcement (σ) and the allowable probability of reinforcement corrosion (P0) at the falure condition of a reinforced concrete structure. 4) This method is also applicable to the design of the quality of concrete and finishing materials required for providing durability and to the estimation of the remaining service life of existing reinforced concrete structures.