An old version of Japanese concrete code based on the AIJ standard for structural calculation of Reinforced Concrete Structures (1985 edition) was previously implemented in STAAD.Pro batch mode design. Recently, critical errors in the column design and beam design were discovered and corrected. In addition, the AIJ concrete design has been udpated to incorporate the latest AIJ standard for structural calculation of Reinforced Concrete Structures (1991 edition). .

Generally, this implementation will be invisible to you. The 1985 edition of the AIJ has been completely replaced by the 1991 edition for the design of concrete members per the AIJ. The existing commands as described in D9.A. Japanese Codes - Concrete Design per 1991 AIJ are applicable to the 1991 edition.