This paper reports the results of a series of 1G-shaking table tests using a medium-size laminar soil box to investigate the application of a method of compaction by static press-in of log piles into loose sandy soil, which can simultaneously provide liquefaction countermeasures and carbon stock. In this study, the improvement effect was evaluated by comparing the different sizes of improvement areas, focusing mainly on the input acceleration and the penetration settlement and tilt angle of the house model. The results confirm that the liquefaction-induced settlement and tilt angles are effectively reduced when the improvement area is larger than that of the house model.
In this paper, a calibration chamber (pressurized soil tank) that allows independent control of vertical and horizontal stresses has been prepared for soil soundings or the development of small-scale freezing sampling technique under the insitu stress state of the ground. The calibration chamber can measure volumetric strain and shear wave velocity by bender elements, so that the small strain shear moduli of the ground during consolidation can be compared with the results of triaxial tests. The comparison results confirm that the relationship between small strain shear moduli and void ratio, as well as the stress dependency, are consistent with previous studies. It can be concluded that the calibration chamber in this study can adequately measure small strain shear moduli by bender elements.
On March 16, 2022, a 7.4 magnitude earthquake "off the coast of Fukushima" caused damages to the ceiling of several large enclosures, located in Tohoku region. Field survey was carried out at 6 facilities. The damage varied depending on the facility, from large-scale ceiling collapses to small-scale ceiling damage, but common damages such as breakage of hanging bolts, failure of spot welds, and deformation of hangers were observed. Besides, existence of facilities having prepared measures to prevent ceiling fall, such as safety nets, was confirmed. Since falling of heavy ceiling installed in high places could lead to life-threatening injury to users, it is necessary to take measures to prevent the falling, and to protect human life.
In this preliminary report, we report the results of comparing the stiffness and strength of timber for cultural property buildings by destructive and non-destructive tests. In the destructive test, full-scale specimens and defect-free small
specimens were tested by the three-point bending test method, and the defect-free small specimens showed higher strength. In the non-destructive test, the stress wave propagation method and the impact method were used for measurement, and the Young's modulus measured by the impact method tended to be partially low. There is a tendency for the stiffness to be relatively close to the correlation between the destructive test of the full-scale specimen and the non-destructive test by the stress wave propagation method, this result showed the same trend as the result that the dynamic test value is generally said to be higher in stiffness than the static test value.
Installation of electric vehicles (EVs) is focused on to decarbonize transportation and to supply power flexibility for solar and wind power. However, the way to decarbonize the EV charging is not obvious. Hence, this paper analyzes the decarbonized EV charging on the viewpoints of EV users, of electricity retailers and of electric power system, and highlights the challenges. This paper proposes combined menus of EV charging services with home “green” electric bills as the solution of decarbonizing EV charging. The combined menus will be considered as an example of the concept “Place of Use”; services for the movable electric demand.