Forty-five years have passed since the San-yo Shinkansen commenced full operation, and various initiatives for the maintenance and management of the concrete structures have been undertaken during this time. As Japan's population will further decline in the future, it is essential that productivity must be improved through the use of new technologies to allow the proper maintenance and management of the concrete structures and ensure their continued safety. Currently, JR West is testing technologies for constant monitoring of PC structures in a bid to improve inspection work efficiency, labor saving, and safety. It is also working on various ways to improve productivity, including the use of drones, image analysis, and cathodic protection methods. This paper reports on various demonstration initiatives toward the utilization of these new technologies.

In this paper, it is proposed to use an unconstrained gusset plate and a hinge relocation technique to control the damage to RC beam-column joints. The structural behavior of RC beams with BRB connections and relocated plastic hinges is investigated by cyclic loading tests. In the tests on RC beams with BRB connections, the BRB axial force was simulated by a force controlled actuator to simplify the boundary condition of the test setup. Two different details of BRB gusset connections were examined. In one method, the gusset plate was fastened to the end of the RC beam by posttensioned steel rods, whereas it was embedded in the RC beam and anchored there by a stud group in the other method. The test results confirmed that the proposed hinge relocation scheme is effective in controlling the locations of plastic hinges in RC beams so as to prevent the BRBs from being dislocated from the entire structural system as a result of the beam end failure at extreme earthquake scenarios. Both gusset connection details performed satisfactorily by providing sufficient strength and large stiff ness to minimize the deformation loss in the BRB connections.

The soundness of box type tunnels is maintained by ongoing repair of water leakage, flaking as such issues occur. However, the methods defined as standard methods by Tokyo Metro Co., Ltd. had not been updated in many years, and new materials that had become available in intervening years were not introduced. Further, instances of re-degradation of some repaired locations occurred. Therefore, to enable the selection of repair methods suitable for box type tunnels such as water cutoff work and cross-section repair work, and a method for the evaluation of repair methods considering the degradation level of the concrete base material was developed after the required performance and evaluation items were defined. In addition, an operation flow for introducing the method into actual construction work was established. These innovations have made possible the rapid introduction of new technologies.