SEISAN KENKYU
Online ISSN : 1881-2058
Print ISSN : 0037-105X
ISSN-L : 0037-105X
Volume 63 , Issue 6
Showing 1-20 articles out of 20 articles from the selected issue
Introduction to Special Section
Research Flash
  • — Preliminary reports focusing on basins of Tone, Kokai and Kuji rivers —
    Junichi KOSEKI, [in Japanese], Jianliang DENG, Hiroyuki ARAKI
    2011 Volume 63 Issue 6 Pages 705-708
    Published: 2011
    Released: December 27, 2011
    JOURNAL FREE ACCESS
        Some case histories, focusing on those in basins of Tone, Kokai and Kuji rivers, are reported on effects of liquefaction in Kanto region caused by the 2011 Off the Pacific Coast of Tohoku Earthquake. Extensive liquefaction took place in reclaimed lands along these rivers and Tokyo bay, which induced damage to houses, lifeline facilities and river dikes. On the other hand, structures with pile foundation, such as viaducts and tall buildings, that had been located in the liquefied areas did not suffer from structural damage. [This abstract is not included in the PDF]
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Field Report
Research Flash
  • Yukika MIYASHITA, Junichi KOSEKI
    2011 Volume 63 Issue 6 Pages 797-800
    Published: 2011
    Released: December 27, 2011
    JOURNAL FREE ACCESS
        It was clarified that the strength and deformation properties of geo-materials depended on strain rate, and the characteristics or degree of the dependency varied in response to the viscous property of the materials. To investigate the effect of strain rate on strength and deformation properties of cement-treated sand, a series of triaxial compression tests was conducted while strain rate was changed stepwise by a factor of up to 1000 in each test.
    Characteristics of the dependency on strain rate changed with the progress of loading, due to the large deformation along the shear band. [This abstract is not included in the PDF]
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  • Yukika MIYASHITA, Junichi KOSEKI
    2011 Volume 63 Issue 6 Pages 801-804
    Published: 2011
    Released: December 27, 2011
    JOURNAL FREE ACCESS
        It was clarified that the strength and deformation properties of geo-materials depended on strain rate, and the characteristics or degree of the dependency varied in response to the viscous property of the materials. To investigate the effect of strain rate on strength and deformation properties of cement-treated clay with high strength, a series of triaxial compression tests was conducted while strain rate was changed stepwise by a factor of up to 1000 in each test.
    The stress-strain relationship at a certain level shifted to that of higher/ lower level after indicating high stiffness and subsequent yielding, when the strain rate suddenly increased/ decreased. [This abstract is not included in the PDF]
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  • Hiromasa NAKAGAMI, Noriyuki TAKAHASHI, Ho CHOI, Yoshiaki NAKANO
    2011 Volume 63 Issue 6 Pages 805-809
    Published: 2011
    Released: December 27, 2011
    JOURNAL FREE ACCESS
        The objective of this study is to develop a seismic capacity evaluation method of R/C buildings with irregular plan configuration under translational responses. An irregular shape building is divided into two building blocks connected with floor slabs, and each block is modeled to a single degree of freedom system connected with a shear spring representing a slab. Time history response analyses and an estimating method based on the static force equilibrium are employed to evaluate the seismic capacity of the building with different mass and strength of each block as well as in-plane stiffness and hysteresis characteristics of connecting slab. [This abstract is not included in the PDF]
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  • Miho OHARA, Kimiro MEGURO, Atsushi TANAKA
    2011 Volume 63 Issue 6 Pages 811-816
    Published: 2011
    Released: December 27, 2011
    JOURNAL FREE ACCESS
        After the off the Pacific coast of Tohoku Earthquake occurred on March 11, 2011, numerous aftershocks continued and a lot of Earthquake Early Warnings (EEW) were announced although some of them failed to estimate intensity properly due to technical limitation. In this paper, two questionnaire surveys were conducted to understand people’s awareness of EEW before and after the earthquake on March 11, 2011. As a result, it was verified people’s knowledge and their abilities to recognize EEW after hearing or seeing the warning increased. When they knew the technical limitation before the earthquakes, their capacities to accept the failure of EEW was higher. [This abstract is not included in the PDF]
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  • Hidetoshi YOSHINARI, Miho OHARA, Kimiro MEGURO
    2011 Volume 63 Issue 6 Pages 817-822
    Published: 2011
    Released: December 27, 2011
    JOURNAL FREE ACCESS
        The Japan Meteorological Agency (JMA) was started the public service of earthquake early warning (EEW) since October 1st, 2007. The number of earthquakes that EEW was announced since October, 2007 is too limited to evaluate the effectiveness of EEW properly. Therefore, in this research, using the data of the past earthquakes’ occurred from 1923 to 2007, expected lead times before S-waves were analyzed based on the assumption that EEW system had been operated before those earthquakes. In addition, the effect of increasing seismometers in the future was also simulated. Based on the results obtained in both current and future cases, regional characteristics of expected lead times of EEW and their damage mitigation effect in each region were revealed, and future strategies for making the best use of EEW were discussed. [This abstract is not included in the PDF]
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