GOTOU Humihiko

写真a

Affiliation

Graduate School of Engineering Science  Department of Systems Design Engineering  Civil and Environmental Engineering Course 

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Research Interests 【 display / non-display 】

  • 構造工学

  • 木構造

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Graduate School 【 display / non-display 】

  • 　
    -
    1994.03

    Tohoku University  Graduate School, Division of Engineering  Doctor's Course  Completed

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Campus Career 【 display / non-display 】

  • 2016.04
    -
    Now

    Akita University   Graduate School of Engineering Science   Department of Systems Design Engineering   Civil and Environmental Engineering Course   Professor  

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Research Areas 【 display / non-display 】

  • Social Infrastructure (Civil Engineering, Architecture, Disaster Prevention) / Structure engineering and earthquake engineering

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Qualification acquired 【 display / non-display 】

  • High School Teacher Specialization License (first and second kind,specialization)

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Thesis for a degree 【 display / non-display 】

  • A numerical technique for finite displacement problems of spacial frames

    後藤文彦 

      1994.03

    Single author

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Research Achievements 【 display / non-display 】

    ◆Original paper【 display / non-display 】

  • ESTIMATION OF VIBRATION CHARACTERISTICS OF MEOTO BRIDGE USING TABLETS WITH ACCELEROMETER

    OIKAWA Daisuke, IWASAKI Keito, GOTOU Humihiko, AOKI Yukari

    Japanese Journal of JSCE ( Japan Society of Civil Engineers )  79 ( 7 ) n/a   2023  [Refereed]

    Research paper (journal)  

    <p> It is important to understand vibration characteristics of bridges for estimation of the stiffness of the entire bridge. Generally equipments for vibration measurement are so expensive that everyone can not easily carry out the measurement using the equipments. In this study, we try vibration measurement with enough accuracy using tablet devices with accelerometer for a timber pedestrian bridge. For the most dominant vertically-antisymmetrical mode, error of measured value by the tablet devices to the numerically calculated value is about −4.0%. It shows the utility of vibration measurement using tablet devices with accelerometer. Besides, we discuss vibration characteristics for the measured timber pedestrian bridge, comparing values of natural frequency and of damping constant with the values obtained by the approximate equation for steel/concrete bridges.</p>

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  • STRUCTURAL PERFORMANCE AND SOUNDNESS EVALUATION OF AGING TIMBER ARCH HIGHWAY BRIDGE

    Daisuke OIKAWA , The Late Genjiro SUGANUMA, Hideyuki HONDA and Humihiko GOTOU

    Paper Reports on Wood Engineering ( Japan Society of Civil Engineers )  19   72 - 79   2021.02  [Refereed]

    Research paper (journal)   Domestic Co-author

  • DEGRADATION EVALUATION FOR MEMBERS OF A TIMBER BRIDGE, WHICH HAS BEEN IN SERVICE FOR 27 YEARS

    OIKAWA Daisuke, FUJIWARA Arisa, GOTOU Humihiko, NODA Ryu, ISHIKURO Shun

    Journal of Japan Society of Civil Engineers, Ser. E2 (Materials and Concrete Structures) ( Japan Society of Civil Engineers )  77 ( 5 ) I_45 - I_54   2021  [Refereed]

    Research paper (journal)  

    <p> In the history of glued timber bridges in Japan 34 years passed since the first bridge was built in 1987, which is much shorter than that of Europe and the United States. Data about stiffness and strength for glue-laminated timber bridges, which have been in service for more than 20 years and then replaced, have not been enough accumulated. In this study, we measure stiffness and strength for the members of Meoto Bridge replaced in 2020 by static/dynamic methods. As a result, the stiffness of the main structural members, such as arch ribs and stiffeners, was generally reduced by about 10%, while design stresses for the arch members and the floor girders are within the allowable stresses. Thus it is suggested that timber members, which have been in service for more than 20 years, have enough stiffness and strength.</p>

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  • NUMERICAL MODELIZATION OF TIMBER CONSTRUCTION MATERIALS CONSIDERING EFFECT OF KNOTS

    KIMIJIMA Mami, AOKI Yukari, GOTOU Humihiko, VALIPOUR Hamid

    Journal of Japan Society of Civil Engineers, Ser. E2 (Materials and Concrete Structures) ( Japan Society of Civil Engineers )  77 ( 5 ) I_1 - I_7   2021  [Refereed]

    Research paper (journal)  

    <p> Recently, "reduction of CO2 emission" has been raised as a most important topic needed to be solved immediately all over the world and each country has declared its reduction target. It is known that construction industry shared the highly CO2 emissions. Thus the new sustainable materials and/or construction methods must be developed as soon as possible. In this research, it is a final target to develop a new timbersteel hybrid beam as a new sustainable material. It is expected to use timbers for the construction site to reduce CO2 emissions than the ordinal materials such as concrete and steel, so that timbers are now one of the most recognized as a sustainable material. In order to replace the concrete to timbers, the timber beam should have the same or even stronger strength than concrete. Thus, in this research timber and steel are combined to improve the beam engineering characteristics.</p><p> In this paper, as a first step to develop such a sustainable beam, knots are presented in the timber beam, because it is found that knots on the beam showed significant reduction of the strength of the beam according to experimental researches. It is shown that knots on the beam have unique material properties and linearly analyzed using FEM. The results of beams are presented in this paper.</p>

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  • COLLAPSE BEHAVIOR OF CLT DECK WITH STEEL RAILING POST

    OGAWA Kouki, GOTOU Humihiko, SASAKI Takanobu, ARAKI Shogo, AOKI Yukari

    Journal of Japan Society of Civil Engineers, Ser. E2 (Materials and Concrete Structures) ( Japan Society of Civil Engineers )  77 ( 5 ) I_55 - I_63   2021  [Refereed]

    Research paper (journal)  

    <p> While CLT(Cross-Laminated-Timber), which is lightweight and is resistant to fatigue, is expected to apply to bridge deck, it is needed to joint commercially available railing on it. It is important to confirm the safety and to investigate the load bearing performance of the joint part between the railing post and the CLT deck. We show relatively simple modeling of the joint part using general-purpose 3D FEM tool and illustrate the numerical results. The modeling considering elasto-plasticity for both steel and CLT members seems to well simulate the sink deformation behavior of CLT.</p>

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    • display all >>

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    ◆International conference proceedings【 display / non-display 】

  • Construction Examples of On-Site Timber Stress-Laminated Box-Beam Bridges

    Tomohumi Huzita, Humihiko Gotou, Takanobu Sasaki, Ryu Noda

    World Conference on Timber Engineering     2018.08

    Research paper (international conference proceedings)   Domestic Co-author

  • Spacial Beam Analysis using Rotation Group and Rotational Angles about Three Axes

    Humihiko Gotou, Takashi Kuwataka, Tetsuo Iwakuma

    Advances in Computational Engineering & Sciences   1   837 - 842   2000.08

    Research paper (international conference proceedings)   Domestic Co-author

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    ◆Research society, Symposium materials, etc.【 display / non-display 】

  • Effect of repeated freeze-thaw cycles on the bending strength of wood

    NODA Ryu, ISHIBASHI Kenya, GOTOU Humihiko

    MOKUZAI HOZON (Wood Protection) ( JAPAN WOOD PRESERVING ASSOCIATION )  46 ( 5 ) 251 - 258   2020  [Refereed]

    Research paper (research society, symposium materials, etc.)   Domestic Co-author

    In civil engineering structures constructed in cold snowy regions such as Hokkaido or Tohoku, repeated freezing and thawing of the wooden materials may occur in winter. To understand how the strength of wood changes because of these freeze-thaw cycles, we evaluated the bending strength of both untreated and preservative-treated Sugi (<i>Cryptomeria japonica</i> D. Don) timber under five regimes of freeze-thaw cycles, while varying moisture content.<br>
    Each cycle lasted 24 hours, and freeze-thaw regimes were composed of 0, 15, 45, 75, and 90 consecutive cycles. After each sample was subjected to a freeze-thaw regime, a bending test was carried out. There was almost no difference among the values of modulus of rupture or modulus of elasticity in samples subjected to different regimes. Moreover, as modulus of rupture and modulus of elasticity may increase after repeated freeze-thaw cycles, we concluded that the effect of the freeze-thaw cycles on the bending strength of Sugi timber is small.

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    ◆Other【 display / non-display 】

  • Collapse behavior of steel railing post considering installation and replacement on CLT deck

    Ogawa Koki, Gotou Humihiko, Sasaki Takanobu, Araki Shogo, Imai Makoto

    Journal of Structural Engineering, A ( Japan Society of Civil Engineers )  70A ( 0 ) 885 - 893   2024  [Refereed]

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  • INFLUENCE OF PARTIAL DECAY OF TIMBER BRIDGE MEMBERS ON NATURAL FREQUENCY

    Oikawa D.

    Journal of Japan Society of Civil Engineers ( Journal of Japan Society of Civil Engineers )  12 ( 1 ) n/a   2024  [Refereed]

    <p> In the inspection of existing bridges, measurement of natural frequency by vibration test is relatively safe and easy. The natural frequency can also be obtained from numerical analysis. In this study, we numerically investigated influence of partial decay of timber members, such as arches and joints between columns and girders, on the natural frequency of deck-type timber arch bridges. Concretely, we estimated sensitivity of the decay parts using the regression plots between natural frequency and magnification to the original Young’s modulus of the decay parts. The results showed that the decay at the part of the vibration antinode was highly sensitive, while the vibration node was low-sensitive. Lastly, we tried to estimate the actual state of decay of the target bridge adjusting parameters, such as Young’s modulus and specific weight, so that the natural frequency could fit the measured value.</p>

    DOI CiNii Research

  • SNOW REDUCTION PERFORMANCE OF DECK-OPENABLE TIMBER BRIDGE TO REDUCE SNOW LOADS

    OIKAWA Daisuke, NODA Ryu, GOTOU Humihiko, AOKI Yukari, MORIOKA Yoshimi

    Japanese Journal of JSCE ( Japan Society of Civil Engineers )  80 ( 28 ) n/a   2024  [Refereed]

    <p> Pedestrian bridges over mountainous areas in Akita Prefecture are in danger of falling because of heavy snow load during winter. The most trivial approach to prevent such snow trouble is increase stiffness of the bridges, while the approach is not so efficient for season-depending load increase. In this study we propose deck-openable timber bridge, whose deck is openable so that the opening can make snow fall down for winter period. In order to estimate the snow reduction performance of the deck-openable bridge, we carried out outdoor exposure test in one of the heaviest snowfall areas in Akita Prefecture.</p><p> As a result, the snow load was reduced by 50% compared to the case of the deck-closed form of the deck-openable bridge.</p>

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  • Elastic Modulus Correction Formula Obtained Using a Stress Wave Propagation Method

    Noda Ryu, Suenaga Yuki, Gotou Humihiko

    Mokuzai Gakkaishi ( The Japan Wood Research Society )  67 ( 2 ) 93 - 99   2021.04  [Refereed]

    <p>To evaluate the strength of structural members using a stress wave propagation method, it is necessary to determine a constant elastic modulus value, regardless of the sensor insertion position and distance between the sensors. Therefore, the elastic modulus values of sugi (<i>Cryptomeria japonica</i>), hinoki (<i>Chamaecyparis obtusa</i>), akamatsu (<i>Pinus densiflora</i>), and karamatsu (<i>Larix kaempferi</i>), which have been used for wooden civil engineering structures, were evaluated while varying the sensor insertion position and the distance between sensors. The elastic modulus was found to be larger when the sensor was inserted between the structural member cross sections, rather than between the surfaces. Moreover, a positive correlation between elastic modulus and distance between sensors was discovered. Subsequently, a correction formula was devised that ensures that the elastic modulus is constant, regardless of sensor insertion position and distance between sensors, with the correction formula calculated for each of the examined wood species.</p>

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Grant-in-Aid for Scientific Research 【 display / non-display 】

  • Grant-in-Aid for Scientific Research(C)

    Project Year： 2023.04  -  2026.03 

  • Grant-in-Aid for Scientific Research(B)

    Project Year： 2021.04  -  2025.03 

  • Grant-in-Aid for Scientific Research(C)

    Project Year： 2020.04  -  2023.03 

  • Grant-in-Aid for Young Scientists(B)

    Project Year： 2001.04  -  2003.03 

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