The Japan Concrete Institute published “Recommendations for Concrete Pumping Methods 2023” in March 2023. These Recommendations are comprised of 10 chapters and 19 related documents included as reference documents. This paper gives an overview of these Recommendations, focusing on three new key points, namely 1) Clarification of average discharge rate, specified discharge rate, and required discharge rate; 2) Presentation of a method for calculating the pumping load from pumping operations using a boom and using pipes; and 3) Provision of standard values for pressure loss (K) inside pipes for ordinary concrete with a water-to-cement ratio of 45％ to 65％.

The JSCE Standard Specifications for Concrete Structures ─Design─ was revised for the first time in five years in March 2023, and this paper gives an overview of this Revision. This revision aims to cover a broader array of conditions related to structures. To this end, the scope of application has been extended to existing structures; encompasses not only ground motions but also impacts, tsunamis, and floods as accidental actions; the scope of application of reinforcement strength has been changed to include high-strength reinforcing bars; coordination between design, construction, and maintenance has been made smoother; the meaning of characteristic values and design values for material properties has been clarified; the safety factors used in durability design and durability verification have been clarified; and the technical content concerning structural design and durability design has been augmented in line with technological advances.

In line with the notice regarding the “Design Standards for Railway Structures (Concrete Structures)” issued in December 2022, the “Design Standards for Railway Structures and Commentary (Concrete Structures)” were published in January 2023. These Design Standards reorganize the existing design standards, which were primarily established for each type of structure and material. They consist of four parts, namely Part I Basic Principles, Part II Bridges, Part III Concrete Structures, and Part IV Support Structures. Additionally, to optimize structures within the railway system, these Design Standards stipulate various design methods for achieving appropriate assessments of redundancy and robustness, rationalization of reinforcement and dimensions, as well as proper evaluation of damage locations and the sequence of damage.

3D Construction printers using cement-based materials are expected to bring innovation such as digital fabrication and automation of building construction. In this study, we developed a composite structure, in which the outer part was laminated with mortar for 3D printer, and the inner part was filled with ultra-high strength fiber-reinforced concrete (UFC). Then, a building was constructed for the purpose of collecting knowledge about the design and construction using this method. The result indicates that building can be constructed. In addition, because The building uses new materials and new construction methods, it has obtained national certification for structural strength.

In recent years in Japan, issues such as the aging of infrastructure have led to visible signs of damage, such as cracking, in reinforced concrete deck slabs. As one solution to this problem, UFC slabs made of ultra high strength fiber reinforced concrete have been developed, but the ultra high strength of UFC raises concerns about spalling phenomena under exposure to high temperatures. This paper reports on the results of fire resistance tests reproducing a fire directly under a bridge with UFC slabs that were conducted for the following three aims: 1) estimate the occurrence of damage and the heating temperature of each member; 2) determine the impact on maximum shear strength and shear constant of headed studs, which are essential determinants of composite behavior when UFC deck slabs are applied to composite girder bridges, and 3) determine the temperature rise suppression effect of fire­resistant coating applied to UFC as a fire protection measure.