Since Freeman announced the capacity spectrum method in 1978, this method has been studied as one of the simple nonlinear response estimation methods. In Japan, owing to the revision of building-related standards for performance standardization in 2000, this method was added to seismic design methods as a limit strength calculation method. Taking into account subsequent research findings, in 2019, the Architectural Institute of Japan published “AIJ Seismic Performance Evaluation Guidelines for Reinforced Concrete Buildings Based on the Capacity Spectrum Method,” which includes building modeling, methods of analysis, and assurance design methods. These are AIJ's first guidelines for the capacity spectrum method, and they are expected to contribute to the popularization of this method in the future.

The use of binders using ground granulated blast-furnace slag, which is one of the initiatives for concrete materials aimed at reducing environmental impact, bears consideration. A vast amount of knowledge about blast furnace cement Class B has been accumulated over the years and its use has been steadily promoted. On the other hand, the use of cement with a high substitution rate that is equivalent to blast furnace cement Class C has not made much progress. This paper gives an overview of the Recommendations for Design and Construction of Concrete Using Ground Granulated Blast-Furnace Slag, which have been revised for the first time in a quarter century. The content was revised in line with the 2017 Standard Specifications for Concrete Structures to allow design and construction based on the latest standards. Further, newly obtained knowledge and new usage methods have been summarized in the Appendix.

Under the “Projects related to the introduction and utilization of innovative technologies to dramatically enhance productivity at construction sites (PRISM)” scheme, in FY 2018, we conducted a “trial on the digitization of information related to ready-mixed concrete, from shipping to placing and quality control, for sharing on the cloud,” applied to multiple construction works implemented by the Ministry of Land, Infrastructure, Transport and Tourism. As a result, insights were gained regarding the effective use of digitized information related to ready-mixed concrete, and it was clearly found that the digitization of ready-mixed concrete-related information is effective for improving both on-site productivity and concrete construction quality. It is hoped that this report will serve as material for discussion for the wide use of this method in the future.