“AIJ Standard for Structural Design and Construction of Prestressed Concrete Structures” was first published in 1961 and has been revised a number of times over the course of the nearly 60 years since then. More than 20 years have passed since the last revision in 1998, and a number of issues have been pointed out in the current standard. Moreover, taking into account inconsistencies between the latest information in the “Guidelines for Structural Design and Construction of Prestressed Concrete Building Based on Performance Evaluation Concept (Draft)” published in 2015, it was decided to issue a major revision of the standard, including its organization. This commentary provides an overview of this latest revision of the standard, which is scheduled to be published in March 2022, and its major changes.

When a silver nitrate（AgNO₃）solution is sprayed on a section of concrete in which chloride ions have penetrated from the outside, the areas containing more than a certain amount of chloride ions turn white, while the other areas turn brown. Based on this phenomenon, a test method to quickly visually check the penetration depth of chloride ions was established as the NDIS 3437 standard by the Japanese Society for Non-Destructive Inspection. This report introduces the background of the creation of this standard, an outline of the test method, the principle of the AgNO₃ solution spraying method, and the points to be noted regarding its implementation.

The compacting of concrete is an important work process that affects the performance of concrete after hardening. Traditionally, the degree of compaction of concrete is evaluated visually based on the changes in the condition of the concrete surface, and this evaluation is largely dependent on the experience of the technician performing the compaction work. As an alternative to visual evaluation by technicians, the authors have devised and verified an AI-based judgment method. They confirmed that AI can judge the completion of compaction in real time in a manner similar to that of technicians by assigning technicians' judgments as correct answer labels to the frame images obtained from the concrete compaction video and by taking into account numerical data indicating the properties of the concrete in the fresh state, such as slump and air content.

The Quasi-Zenith Satellite System (Michibiki) commenced service in Japan since November 2018, and effective uses of this system are being developed in various fields. Based on this background, the authors have focused on two types of applications of satellite information in the field of building structures: Measurement of long-term building global deformation over several years, and measurement of seismic response displacement of buildings caused by earthquakes, etc. This paper outlines the measurement method and the results, and discusses the findings and future directions.