MURAKAMI Masahide

    Department of Architecture Professor
Last Updated :2024/04/25

Researcher Information

Degree

  • (BLANK)

URL

J-Global ID

Research Interests

  • 木質構造   Timber astructures   

Research Areas

  • Social infrastructure (civil Engineering, architecture, disaster prevention) / Building structures and materials

Education

  •        - 1986  University of Tsukuba  工学研究科  構造工学
  •        - 1986  University of Tsukuba  Graduate School, Division of Engineering
  •        - 1981  University of Tsukuba  第三学群  基礎工学類構造工学主専攻
  •        - 1981  University of Tsukuba  Third Cluster of College

Association Memberships

  • 日本木材学会   木造建築フォーラム   日本建築学会   

Published Papers

  • Nobuhiko AKIYAMA; Shigefumi OKAMOTO; Tomohiro MORIMOTO; Shigeaki KAWAHARA; Takuro MORI; Hiroshi ISODA; Masahide MURAKAMI
    Journal of Structural and Construction Engineering (Transactions of AIJ) Architectural Institute of Japan 86 (788) 1452 - 1463 1340-4202 2021/10
  • THEORETICAL FORMULA TO PREDICT THE ULTIMATE SHEAR CAPACITY OF SHEATHED SHEAR WALLS WITH ANY NAILING ARRANGEMENT PATTERN Comparison between values calculated from theoretical equations and regression equations
    Masahide MURAKAMI
    Journal of Structural and Construction Engineering (Transactions of AIJ) 785 1068 - 1073 2021/07 [Refereed]
     
    The formula for the full plastic nail arrangement modulus Zpxy which is used in the calculation of the ultimate shear capacity of the sheathed shear walls with any nail arrangement was theoretically derived by using the upper bound theorem. The unknown values are the rotation ratio (qx/qy) and the neutral axis positions (xo and yo) in the calculation. The difference between the calculation with the elastic values and the plastic values as unknown values is within 1.5%.
  • 各種釘配列した面材張り大壁のせん断座屈の予測法
    村上 雅英; 小宅 智己; 小谷 竜城
    日本建築学会構造系論文集 781 449 - 456 2021/03 [Refereed]
  • 木質ラーメンにおける弾塑性挙動の簡易計算手法の提案
    小谷 竜城; 小宅 智己; 村上 雅英
    日本建築学会技術報告集 65 172 - 177 2021/02 [Refereed]
  • CLT二方向フラットスラブの設計用面外曲げFEM解析方法の開発と検証
    江坂 佳賢; 村上 勝英; 三松 あずさ; 本田 貞光; 塩崎 征男; 小松 賢司; 村上 雅英; 稲山 正弘; 井田 茉利
    日本建築学会技術報告集 62 103 - 108 2020/02 [Refereed]
  • 集成材有孔梁の補強方法の検討
    小谷 竜城; 小宅 智己; 林 拓磨; 村上 雅英
    日本建築学会技術報告集 61 1091 - 1096 2019/10 [Refereed]
  • 重ね梁形式のCLT二方向フラットスラブの設計方法に関する実験的研究
    村上勝英; 三松あずさ; 江坂佳賢; 塩崎征男; 小松賢司; 村上雅英
    日本建築学会技術報告集 57 607 - 612 2018/06 [Refereed]
  • 木質面材を鉄骨フレームに嵌め込んだ耐力壁の開発
    秋山信彦; 岡本滋史; 森本知宏; 村上雅英
    日本建築学会技術報告集 57 613 - 618 2018/06 [Refereed]
  • CLTの継ぎ目をせん断キーで補強した水平構面の面内せん断性能に関する研究
    岡本滋史; 安曇良治; 車田慎介; 河村進; 村上雅英
    日本建築学会技術報告集 57 631 - 636 2018/06 [Refereed]
  • 軸力作用下におけるGIR接合部のモーメント抵抗性能の評価手法の開発および設計事例への適用
    江坂佳賢; 村上勝英; 村上雅英; 稲山正弘
    日本建築学会構造系論文集 57 637 - 642 2018/06 [Refereed]
  • 集成材の繊維平行方向に埋め込まれたラグスクリューボルト接合部の引抜性能算定式の提案及び検証
    小谷竜城; 村上雅英; 青木謙治; 稲山正弘
    日本建築学会構造系論文集 748 847 - 857 2018/06 [Refereed]
  • 瀧野敦夫; 八神紗良; 村上 雅英
    日本建築学会技術報告集 56 141  2018/02 [Refereed]
  • Ryuki Odani; Teruki Kitagawa; Kenji Aoki; Masahiro Inayama; Masahide Murakami
    Journal of Structural and Construction Engineering Architectural Institute of Japan 83 (744) 285 - 295 1881-8153 2018/02 [Refereed]
     
    The purpose of this paper is to elucidate the pull-out resistance mechanism of the lagscrewbolt joint embedded in parallel to the grain of timber and to lead to the proposal of the design method. In this paper the state of stress and strain of lagscrewbolt joint is examined by numerical analysis because of difficulty of the experimental confirmation. Elastic analysis by FEM model was conducted and the results were compared with the experimental results. At the end, the pull-out resistance mechanism was clarified.
  • Masahide Murakami; Yoshiharu Azumi
    Journal of Structural and Construction Engineering Architectural Institute of Japan 82 (732) 239 - 246 1881-8153 2017/02 [Refereed]
     
    The stiffness and shear capacity of nailed sheathed shear walls are calculated by summing up the resistance force of nails assuming that sheets don't buckle and are not damaged by shear. High strength shear walls are designed based on calculation without considering the limitation of the existing formulae. The limitation of this formulae is determined in this paper based on experimental and analytical studies. It is demonstrated that the findings of the work reported by the authors are applicable regardless of the material type and size of sheets. The critical shear buckling stress of sheathed shear walls with stiffening with studs are estimated to be twice the theoretical critical shear buckling stress of sheathed shear walls without studs whose edges are simply supported. The method to determine the limitation of the existing formulae for the calculation to design high strength shear walls are presented.
  • Yoshiharu Azumi; Masahide Murakami
    Journal of Structural and Construction Engineering Architectural Institute of Japan 81 (724) 981 - 991 1881-8153 2016/06 [Refereed]
     
    Most formulae to calculate the shear stiffness of a sheathed shear wall are derived under the assumption of rigid frames connected with pins. But the flexural and axial deformation of vertical studs affects the shear stiffness of a shear wall. A few other conventional formulae to calculate the shear stiffness of a sheathed shear wall consider only the effect of the flexural deformation of vertical studs. Since there is no calculation method of the shear stiffness considering the effect of the flexural and the axial deformation of vertical studs, numerical analyses are conducted. In this paper, we derive simplified formulae based on the principle of minimum potential energy. The formulae are verified by numerical static elasticity analyses.
  • Ryuki Odani; Masahide Murakami; Masahiro Inayama
    Journal of Structural and Construction Engineering Architectural Institute of Japan 81 (722) 757 - 767 1881-8153 2016 [Refereed]
     
    The purpose of this paper is to appropriately judge the decision method for exponents of verification formula for combined stress in the safety side. The decision method allows it to determine by showing the evaluation standard that derived by mechanical model. It shows that a decision method of exponents, which this paper suggests, for the bending moment resisting joints by drift-pin joint is appropriate. The validity of the decision method is inspected by numerical analysis, an experiment and a past research for the evaluation standard that derived by mechanical model.
  • Yoshiharu Azumi; Ryuki Odani; Takeshi Nakagawa; Shigefumi Okamoto; Masahide Murakami
    Journal of Structural and Construction Engineering Architectural Institute of Japan 81 (721) 595 - 605 1881-8153 2016 [Refereed]
     
    Evaluate methods of short-term basic shear strength of a gable roof diaphragm in experiment and in calculation are inconsistent because these methods are assumed to be different yield mode. The evaluation method for shear performance of a gable roof diaphragm in the experimental procedure and in the calculation procedure with the assumption of same yielding mode is presented in this paper. When the maximum strength of a roof diaphragm is due to yielding nail joints between panel and rafter, short-term basic shear strength per unit length of a roof diaphragm is verified that well agrees regardless of pitch of roof and size by experiments and numerical analyses.
  • Kazuyoshi Komoto; Yoshiharu Azumi; Masahide Murakami; Masahiro Inayama
    Journal of Structural and Construction Engineering Architectural Institute of Japan 81 (719) 79 - 89 1881-8153 2016/01 [Refereed]
     
    In recent years, Japanese exposed-post and beam style rooms made with panels nailed onto wooden framework structures, or Menzai-Shin-Kabe, have become more common than the traditional mud plaster on laths method, called Tsuchi-kabe. Menzai-Shin-Kabe is the method of nailing sheathing materials, such as structural plywood, onto studs placed in between exposed-post framework. The formulae to calculate the elastic stiffness, yield point, ultimate strength and the ductility factor of Menzai-Shin-Kabe have been derived from the elements of the shear resistance of the nails hammered into the studs and bedding frames, and the truss effect from the diagonal compression resistance of the sheathing material. In order to verify the scope of application of the formulae, shear racking tests of sheathed walls have been carried out where plywood is employed as the sheathing material.
  • Masahide Murakami; Yoshiharu Azumi; Yoshitaka Ohshita
    Journal of Structural and Construction Engineering Architectural Institute of Japan 80 (716) 1569 - 1578 1881-8153 2015 [Refereed]
     
    The stiffness and capacity of nailed sheathed shear walls are calculated by assuming that sheets don't buckle. There is no way to predict the critical stress of shear buckling of nailed sheathed shear walls. The effect of shear buckling is not considered in the examination of sheets against shear failure when structural design of high strength sheathed shear walls is carried out. Two formulae are experimentally found in this paper: one formula is to predict the critical stress of shear buckling considering the restriction of rotation along edges of sheets with nails the other is to express the relation between shear strength of plywood sheets and critical stress of shear buckling in nailed sheathed shear walls.
  • Yoshiharu Azumi; Masahide Murakami
    Journal of Structural and Construction Engineering Architectural Institute of Japan 80 (707) 93 - 103 1881-8153 2015 [Refereed]
     
    The sheathed shear elements (i.e. shear walls and horizontal diaphragms) play an important role in the wind and seismic resistance of wooden structures. When sheathed shear elements are used as a horizontal diaphragm, they are reinforced with shear keys along panel joints to increase the shear stiffness and strength. A simplified formula to predict the performance of sheathed shear elements reinforced with shear keys along panel joints is derived in this paper. Influences that the ratio C of the stiffness of nails to that of shear keys have on the performance of sheathed shear elements are discussed in Chapter 2. The simplified formula to predict the performance of sheathed shear elements is derived in Chapter 3. The validity of a simplified formula is examined with numeral analyses that consider the size of sheathed shear elements, the ratio C of the stiffness of nails to that of shear keys and the aspect ratio and number of panels in Chapter 4. The simplified formula to predict shear stiffness of a sheathed shear element (Fig.5) is derived by the energy method based on the following assumptions: (1) The resisting mechanism of sheathed shear elements can be divided into the horizontal component (X direction) and the vertical component (Y direction) (Fig.7). These two components can be connected in series. (2) The vertical component consists of two deformation modes, i.e. the rotation of panels (MODE1) and the translation in the Y direction (MODE2) (Fig.8). (3) The rotational angles, θx and θy, of each panel in the X and Y directions are equal. (4) The influences of friction between panels in large deformation are negligible. The yielding strength of sheathed shear elements is calculated by comparison of the yielding loads of nails at three points on the outer panel and the adjacent panel to it (Fig.12) and those of shear keys along two panel joints (Fig.11). The ultimate strength of the sheathed shear elements is calculated for two ultimate states (Fig.13). The formula is verified by comparison with results by two different numerical static elasto-plasticity analyses (Fig.1 and Fig.18) with C as a variable. The comparison between the simplified formula and numerical analyses is shown in Figs. 19-26. The calculation result obtained with the formula considering the behavior of all panels well agrees with the analytical results. The formula becomes complicated as the number of panels increases. When the formula is simplified, the validity of the simplified formula depends on the number of panels and the value of C.
  • Atsuo Takino; Yoshiharu Azumi; Shigefumi Okamoto; Takeshi Nakagawa; Tomonori Shibutani; Masahide Murakami
    Journal of Structural and Construction Engineering Architectural Institute of Japan 79 (703) 1329 - 1336 1881-8153 2014/09 [Refereed]
     
    The shear performance, such as stiffness and strength, of floor construction of traditional wooden structures is lower than that of structural plywood because the small width board is used. In the large deformation area, however, increasing shear strength and stiffness are produced by friction between boards. In this study, we suggested the formula to predict the shear performance of floor construction of traditional wooden structures considering the increasing strength produced by friction based on the direct shear performance of nails.
  • Masahide Murakami; Yoshiharu Azumi; Atsuo Takino; Shigefumi Okamoto; Takeshi Nakagawa; Shinsuke Kurumada
    Journal of Structural and Construction Engineering Architectural Institute of Japan 79 (702) 1137 - 1146 1881-8153 2014/08 [Refereed]
     
    Three kinds of simplified formulae to predict shear stiffness and yielding strength of a horizontal diaphragm reinforced with shear keys along panel joints are derived in this paper. The validity of these formulae is discussed based on the comparison of them to numerical analyses. It is shown that their validity depends on the ratio C of the stiffness of nails to that of shear keys.The shear stiffness and yielding strength of a horizontal diaphragm are the best predicted when the fact that the diaphragm behaves as a single panel for a higher C value is considered.
  • 「土質力学に基づく土塗壁の耐力変形推定式の提案 −壁土のせん断破壊が卓越する場合−」に対する討論 (宇都宮直樹,宮本慎宏,山中 稔,松島 学著 日本建築学会構造系論文集,第78巻,第684号,363-368,2013年2月号掲載)
    村上 雅英
    日本建築学会構造系論文集 (693) 2045  2013/11 [Refereed]
  • Tatsuya Imanishi; Toshiyuki Kanyama; Masahide Murakami
    AIJ Journal of Technology and Design 19 (41) 131 - 136 1341-9463 2013/02 [Refereed]
     
    The general method for strengthening unreinforced concrete foundation beams of wooden houses against earthquakes is to arrange reinforcing bars and to cast concrete along the existing foundation beam. The construction cost of this method accounts for major percentage of the total construction cost for strengthening. A new method for flexural reinforcement with steel channel attached to one side of unreinforced concrete foundation beams was developed, which can reduce the cost. Bending moment tests were carried out to check the structural performance. A formula to predict the flexural capacity was obtained as a result of experimental and analytical studies.
  • 村上雅英; 安曇良治; 稲山雅弘
    日本建築学会構造系論文集 (672) 249 - 258 2012/02 [Refereed]
  • Shuntaro Tanaka; Hiroki Matsunaga; Norio Iwata; Masahide Murakami
    AIJ Journal of Technology and Design 18 (38) 125 - 129 1341-9463 2012 [Refereed]
     
    In this paper, we present a new approach to calculate the horizontal load carring capacity of a wooden structure consisting of structural components with different deformation capacities. The conventional perfect elasto-plastic model is found to be improved by adopting a safety limit angle that gives the same potential energy for the individual components.
  • Takayuki Sugimoto; Makoto Kageyama; Norio Iwata; Masahide Murakami
    AIJ Journal of Technology and Design 17 (37) 861 - 866 1341-9463 2011 [Refereed]
     
    Two new low-cost shear walls have been developed, to effectively strengthen a conventional wooden structure without any change in the foundation of the house. The sheathed shear wall with a 330 mm height wooden beam does not require RC beam foundation. The brace shear wall has "all-threaded steel" bars and so-called "hole-down joint metal". Furthermore, a 46-year old wooden house was retrofitted using the two newly developed walls as well as other conventional strengthening's. It was confirmed that after strengthening, all indices are greater than 1.00 and the natural period becomes shorter.
  • Makoto Kageyama; Masahide Murakami
    AIJ Journal of Technology and Design 17 (35) 107 - 112 1341-9463 2011 [Refereed]
     
    This paper elucidated two problems to calculate the structural performance evaluation of the moment resistance timber frame ("frame") with a vertical load by structural analysis on actual design. Problems as follows ultimate strength of the frame that connection is brittle, and frame structural performance that critical section position of columnbeam connection is not on structural axis. For numerical analysis, it is confirmed that ultimate strength of the frame is fallen because of a vertical load, and critical section position should evaluate appropriate position for each connection specification.
  • Shigefumi Okamoto; Masahide Murakami; Mas Ahiro Inayama
    Journal of Structural and Construction Engineering 75 (657) 2019 - 2026 1340-4202 2010/11 [Refereed]
     
    Formulae to predict shear force-drift angle relations of compressive bracing shear walls with arbitrary wall length are proposed in this paper, taking into consideration the equilibrium of forces and friction acting on end of the braces. These formulae are derived assuming the major component of deformation of compressive bracing shear wall is the compression of both ends of a brace into a girder and a sill. These formulae are verified with element tests of brace ends and tests of bracing shear walls.
  • Masahiro Inayama; Masahide Murakami
    Journal of Structural and Construction Engineering 75 (657) 2009 - 2017 1340-4202 2010/11 [Refereed]
     
    According to the moment resistance frame substitution model, the assumed stress state about the N value calculation method to estimate the required tensile force of column's top and bottom joints was explained. The general solution about the tensile force of column's top and bottom joints was derived with the moment resistance frame substitution model and the shear panel substitution model in which the bending stiffness of the beams and the axial stiffness of the joints were considered. It was found by using the general solution with these substitution models that the coefficient "Bi", which is multiplied by the shear wall magnification factor in N value calculation method, was affected by the bending stiffness of the beams and the shear wall length. As a result, the validity and coverage of the coefficient "Bi" became clear. In addition, the approximated values of "Bi" corresponding to each shear wall length were shown in Table 3 for the practical structural calculation as the result of this theoretical study. The tensile force of column's top and bottom joints in various conditions can be obtained accurately by the calculation method of this theoretical study.
  • 岡本滋史; 村上雅英
    日本建築学会技術報告集 16 (34) 945 - 950 1341-9463 2010/10 [Refereed]
  • Ryuki Odani; Makoto Kageyama; Masahide Murakami; Masahiro Inayama
    Journal of Structural and Construction Engineering 75 (654) 1483 - 1490 1340-4202 2010/08 [Refereed]
     
    The current earthquake resistant design code for building in Japan, basically assumed a rigid horizontal diaphragm while calculating the eccentricity and correction coefficient of torsion. Such assumption may cause dangerous design while considering a flexible horizontal diaphragm with large eccentricity for real structure. Considering the shear deformation of floor, calculation method has been presented in this paper for eccentricity and correction coefficient of torsion. In elastic design, eccentric moment caused by earthquake force is generally resisted by the walls both X and Y directions, which in such case show rotation resist effect. Assuming the shear stiffness of the floor and the rotational resistant force from the wall to be in-series, formulae for calculating the eccentricity have been derived. These formulae also are verified by simulating an elastic one span model, using both static analyses and dynamic time history analyses.
  • Makoto Kageyama; Masahide Murakami; Kohei Komatsu
    Journal of Structural and Construction Engineering Architectural Institute of Japan 75 (647) 165 - 173 1881-8153 2010 [Refereed]
     
    The purpose of this study is to establish the evaluation method of the structural performance of connection in moment resistance timber frame under combined stress of bending moment and shearing force.In order to make clear the problem, bending and shearing tests with several different shear span lengths were carried out.Moment capacity of the moment resistance timber frame connection was evaluated accurately by using the shear span length not from connection point of linear elements, but from center position of the shearing resistance at the connection to the inflection point.
  • KOMOTO Kazuyoshi; MURAKAMI Masahide; INAYAMA Masahiro
    J. Struct. Constr. Eng. Architectural Institute of Japan (629) 1127 - 1134 1340-4202 2008/07 
    Generally in Japanese style rooms, sheathed walls with uncovered post have spread instead of mud walls. The sheathing material is nailed and inserted in the frame with noggings. The formula to calculate the elastic strength, yield point, ultimate strength and the ductility of factor has been derived for sheathed wall, considering the elements of the shear resistance of the nail struck in the noggings and frame, and the diagonal compression resistance of the sheathing material as truss action. In order to verify the formula, the shear examinations of sheathed walls have been carried out where five kinds of different sheathing material have been used. It is clear that the formula is sufficiently accurate to predict the elastic and plastic behavior of sheathed walls with uncovered post for structural calculation.
  • FUJII Masaya; INAYAMA Masahiro; MURAKAMI Masahide
    J. Struct. Constr. Eng. Architectural Institute of Japan (628) 931 - 938 1340-4202 2008/06 
    In this paper, the formula to evaluate the required tensile capacities of connections at column's top and bottom for conventional post and beam structural system having sheathed walls with openings, which are extended assuming rigidity of beams and floors in three dimensional structures from one previously derived assuming rigidity of beams in plane structures by authors, is presented and experimentally verified.The formula to evaluate normal force of column consists of the sums of the dead normal force, the normal force caused from the over turning moment by the horizontal shear force acting on upper stories, and vertical shear force produced in the shear wall carrying the shear resistance. The formula has been verified by carrying experiments on a two story three dimension structure with 26 kind variables. Dividing three dimension effect into perpendicularly arranged columns and walls effect to loading direction, the generating mechanisms have been experimentally made clear. For the variable of the bending stiffness of beam, experiments clearly shown that the beam deformation could not been disregarded.
  • HASEMI Yuji; MURAKAMI Masahide; KAWAI Naohito; YAMADA Makoto; YASUI Noboru; OSHIUMI Shiro; SHIMIZU Yosuke; KOBATA Seiji; KAMIYA Hidemi; SAKATA Takahiro; NAGAMORI Hiroki
    AIJ Journal of Technology and Design Architectural Institute of Japan 14 (27) 163 - 168 1341-9463 2008/06 
    In-plane shear tests and loaded fire tests on post-shear test specimens are conducted on one-story tall conventional post-beam wooden walls retrofitted with both-sides panels for the improvement of seismic and post-earthquake fire resistance. The tests have verified high shear and post-earthquake fire performance of 12.5mm thick structural gypsum board, high density gypsum fiberboard, and ceramic-siding and steel-sandwich panel external walls.
  • KAWAGOE Yuko; HASEMI Yuji; KAMIYA Hidemi; KOBATA Seiji; YASUI Noboru; SAKATA Takahiro; NAGAMORI Hiroki; MURAKAMI Masahide
    AIJ Journal of Technology and Design Architectural Institute of Japan 14 (28) 483 - 486 1341-9463 2008 
    To improve disaster prevention performance of wooden densely inhabited district without large-scale urban development, authors are researching and developing The simultaneous seismic & fire-resistive reinforcement. Effectiveness of the reinforcement for the reduction of post-earthquake urban fire hazard is studied using the building data from a historic still crowded "bed town" near Tokyo through the BRI urban fire simulator. From the analysis in consideration of past research1), it was found that the reinforcement has the possibility of efficiently reducing danger of post-earthquake urban fire hazard.
  • Nobuyoshi Yamaguchi; Masato Nakao; Masahide Murakami; Kenji Miyazawa
    2008 SEISMIC ENGINEERING CONFERENCE COMMEMORATING THE 1908 MESSINA AND REGGIO CALABRIA EARTHQUAKE, PTS 1 AND 2 AMER INST PHYSICS 1020 761 - + 0094-243X 2008 [Refereed]
     
    For seismic design, ductility-related force modification factors are named R factor in Uniform Building Code of U.S, q factor in Euro Code 8 and Ds (inverse of R) factor in Japanese Building Code. These ductility-related force modification factors for each type of shear elements are appeared in those codes. Some constructions use various types of shear walls that have different ductility, especially for their retrofit or re-strengthening. In these cases, engineers puzzle the decision of force modification factors of the constructions. Solving this problem, new method to calculate lateral strengths of stories for simple shear wall systems is proposed and named 'Stiffness - Potential Energy Addition Method' in this paper. This method uses two design lateral strengths for each type of shear walls in damage limit state and safety limit state. Two lateral strengths of stories in both limit states are calculated from these two design lateral strengths for each type of shear walls in both limit states. Calculated strengths have the same quality as values obtained by strength addition method using many steps of load-deformation data of shear walls. The new method to calculate ductility factors is also proposed in this paper. This method is based on the new method to calculate lateral strengths of stories. This method can solve the problem to obtain ductility factors of stories with shear walls of different ductility.

Books etc

  • 阪神大震災に見る木造住宅と地震
    鹿島出版会 1997 
    1997-

Works

  • 1995年兵庫県南部地震における鉄筋コンクリート構造物と木構造物の被害調査
    1995
  • Investigations of Reinforced Concrete Structures and Wooden Structures Damaged by the 1995 Hyogoken-Nanbu Earthquake
    1995
  • 島津高圧ジャッキ制御システムの開発
    1993
  • Development on the Shimazu's High Pressure (70MPa) Hydraulic Actuator Control System.
    1993
  • アクチェーター.コンピューターオンライン実験システムのペル国での開発
    1990 -1991
  • Development of the Actuator-Computer Omling testing System in Peru
    1990 -1991

MISC

Awards & Honors

  • 2018/05 Architectural Institute of Japan Prize of AIJ
     木質構造における各種面的な耐力要素の面内せん断抵抗機構の解明と構造計算法の確立に関する一連の研究 
    受賞者: MURAKAMI Masahide
  • 1997 平成9年度コンクリート工学協会論文賞
     JPN
  • 1992 第14回コンクリート工学年次講演会優秀講演賞
     JPN

Research Grants & Projects

  • Japan Society for the Promotion of Science:Grants-in-Aid for Scientific Research
    Date (from‐to) : 2004 -2006 
    Author : MURAKAMI Masahide
     
    The construction way of substrate and the material used in the mud walls are different according to the provinces. The influence of different construction way of substrate on the structural performance of mud walls has not been clear yet, because there are a lot of kinds of construction way and two kinds of failure modes of mud walls. The shear behavior of mud walls can be predicted by our physical model based on their lateral load carrying mechanism. This mechanism mainly consists of the following three elements : 1) Compressive vertical pressure force between soil wall and beam or sill at all corners as compressive bracing action, 2) Compressive vertical pressure force between soil wall and embedded horizontal wooden batten 'Nuki' as dowel action, and 3) Shear resistance of soil wall. The portion-wall specimens which are cut from the mud wall considering the resistance mechanism were examined to presume the envelope curve and the multiplier of bracing unit of it, and the validity of the portion-wall tests was discussed with three kinds of different mud walls. The influence of different specification of mud walls on their structural performance was experimentally investigated by using this experimental technique as a fundamental method of settlement. The experimental parameters of specification were planned based on the questionnaire survey to the constructer in the whole country. The standard specification of these specimens is decided based on the Ministry of Land, Infrastructure and Transport notification. Three sets of experiments were conducted for three years by using three kinds of soils with different strength. The number of effective sample finally used for the evaluation was 114. The influence of compressive strength of soil and the specification of substrate on the structural performance of mud wall was clarified at each lateral load carrying mechanism.
  • Japan Society for the Promotion of Science:Grants-in-Aid for Scientific Research
    Date (from‐to) : 2004 -2006 
    Author : HASEMI Yuji; KOSHIISHI Naoyuki; MURAKAMI Masahide; HATA Toshimitsu
     
    Engineering design method and design examples of load-bearing members such as external walls, room partitions and floor-beam assemblies of Japanese traditional bare-timber construction are presented. Full-scale and small scale fire resistance tests on these members were conducted to develop and verify predictive method for their post-fire integrity and load-bearing capacity The study revealed significance of the long-term loading on the post-fire mechanical performance of these members, which indicates need of structural design based on occupancy consideration. The predictive method has been applied to the structural and fire safety design of a three-story traditional style townhouse and a two-story large nursery facility.
  • Japan Society for the Promotion of Science:Grants-in-Aid for Scientific Research
    Date (from‐to) : 2001 -2003 
    Author : SUZUKI Tamotsu; IIJIMA Yasuo; SASAKI Takanobu; GOTO Masami; MURAKAMI Masahide; KITAHARA Akio
     
    (1)The following fundamental principle was set up for creating a near future type of traditional wooden construction sustainable to any earthquake: 1) to utilize the vibration absorbing, isolating, and controlling mechanisms which exist originally in wooden structures, 2) to apply some kinds of modern simple technique to the construction, and thus, 3) to produce high efficient function of those resistant mechanisms. (2)Several elementary basic techniques to build structures, suitable to the above-mentioned principle, were devised and realized as for materials and constructions of wall, connection, frame, and foundation. (3)The representatives of such basic techniques are cylindrical Laminated Veneer Lumber, improved soil wall with wood lattice, wooden wall made of thick Sugi plates, wooden tenon joint using adhesive, skeleton frame with improved wooden connections, and stone and buried girder foundation system supporting upper-structure without connecting. All of them are resulted from Japanese traditional construction skills and wisdoms. And their validity and usefulness were examined through static tests of componential specimens and a full-scale model house, both of which included each or couple of those techniques. (4)Based on the various results of the previous study, two types of three dimensional unit frame, designated as 'soil wall and Sugi wood plate wall systems', were built and tested on the shaking table in the Institute. The fundamental dynamic characteristics of these wall systems were finally investigated. Thus, the validity and usefulness for the effects of accumulating the devised elementary techniques were satisfactorily confirmed through both tests of three dimensional frames and a full-scale building
  • 日本学術振興会:科学研究費助成事業
    Date (from‐to) : 1999 -2000 
    Author : 村上 雅英
     
    平成11年度には、本研究で提案した柔らかい床剛性を考慮した木造住宅のねじれ挙動の評価法を、地震応答計算と、実大平屋建物の静的破壊実験を行い、理論の妥当性を検証した。それらの結果は、おおむね良好であった。本研究成果として、床の必要耐力の算定法が提案されると共に、本研究と平行して、転ばし根太床などの剛性やせん断耐力の評価法も提案された。それらの成果を踏まえて、平成12年度に施行された住宅の品質確保の促進等に関する法律の「木造住宅の構造安定に関する基準」において、床倍率の概念が導入された。 平成11年度の解析研究では、壁配置と重量配分のバランスの悪さに起因する建物全体の捻れによる変形が、柔らかい床剛性に起因する局部的な床変形の増大と比べて1桁小さいことが明らかとなった。そこで、「見なし規定」として位置づけられる品確法の壁量計算では、剛床仮定による建物全体の捻れの計算を省略し、床に作用するせん断力による床のせん断変形のみを検討の対象とする。その際、終局耐力時に各壁線の耐力の加算則が成立するためには、各壁線のせん断力-層間変位の関係における塑性域が重ならなくてはならない。そのためには、床に作用するせん断力のみから床のせん断変形を算定し、制限する必要がある。また、床に作用するせん断応力度を検定すれば、建物の捻れによる床の先行破壊は防止できる。このような考えに基づいて床倍率の概念が提案された。
  • 日本学術振興会:科学研究費助成事業
    Date (from‐to) : 1999 -1999 
    Author : 鎌田 輝男; 秋山 真一; 村上 雅英; 鈴木 祥之
     
    1995年兵庫県南部地震における木造住宅の被害状況を把握するために、各研究分担者が担当した調査地域の木造住宅被害状況を整理し、木造住宅の構造、形式、規模、建築年代などの建物特性と被害状況のデータベース化を行うとともに、住宅のもつ特性分布や地盤特性などの地理的分布と被害分布を関連づけるために、SISシステム(Spatial Information Ststem)を導入することによって、個々の住宅情報と被害分布を視覚的に表示することが可能となり、また、住宅群を対象として条件検索による被害特性抽出機能によって、建築年数や老朽度、屋根構造、階数、規模といった建物特性による地震被害状況を把握することができるようになった。 震災直後には、建築物の耐震診断に関心が集まり、多くの公共施設において全国的に実施されるようになったが、住宅については、一部地域においてなされただけで、全般的には、関心が薄い。これは、住宅の耐震診断において、これまでは、有効な手法が確立されていなかったためであり、ようやく、単に壁量あるいは壁率といった単一指標でなく、重量の高さおよび平面分布、平面形状、壁配置といった建物特性を取り入れた詳細な耐震診断が可能となり、その結果によって、耐震補強の方策、その効果を評価することができるようになった。耐震補強については、一般に、壁面の剛性および強度を増加させるための手法が取られるが、簡便な手法としては、パネルによる補強、筋違いの挿入、仕口部の金物補強が有効であることが実験的に確認された。
  • 日本学術振興会:科学研究費助成事業
    Date (from‐to) : 1997 -1997 
    Author : 岩井 哲; 橋本 清勇; 北原 昭男; 後藤 正美; 村上 雅英; 鈴木 祥之
     
    1995年1月17日に発生した兵庫県南部地震による住宅などの木造建物の被害では,在来軸組構法の被害が著しく,特に間口の狭い商店や文化住宅などの被害が顕著であった。これは全体的な壁量の不足,または桁行方向に比べ張り間方向の壁が少ないなどの不均衡な壁配置により耐力的に劣る要因によるものと考えられる。従ってこのような建物において,張り間方向の補強に方杖,袖壁,垂壁を有効に配置することは耐震性能の向上につながると考える。 本研究では,袖壁,方杖,袖壁と垂壁などの形態の異なる補強法により耐力壁としてどれほどの耐力,変形性能があるかを定量的に把握した。耐震補強の性能を明確にすることで存来軸組構法の耐震性の向上に繋げることが本研究の目的である。本実験では90cm以下の壁体である袖壁ならびに方杖による補強,補剛の効果を中心に調べている。木造軸組構法の住宅において,地震時の必要壁量の算出における壁率の決定にあたっては,一般に90cm未満の短い壁は壁量として設計に組み込まれておらず,またその耐力は定量化されていない。地震に強い建物の建設,既存の建物の耐震性の向上において開口部を有する壁等の補強後の耐力を数値的に把握しておくことは重要である。木造軸組構法の耐震性の向上に向けて,方杖,袖壁,垂壁,添え住などによる補強を施した種々の試験体による載荷実験を行い,工法・形状の違いによる比較を行って有効な補強方法を明確にした。また建物を耐震補強する際に,施工に要する価格に対してどれほどの補強効果が得られるかについて目安を示した。
  • 日本学術振興会:科学研究費助成事業
    Date (from‐to) : 1996 -1996 
    Author : 鈴木 祥之; 村上 雅英; 鈴木 三四郎; 河村 廣; 岩井 哲; 鈴木 有
     
    本研究は、阪神・淡路大震災において、大被害を受けた木造建物の被害原因を解明し、構造的な耐震補強と設計・施工・維持管理に至る耐震対策を導くことを目的として、被害調査、地盤での微動および余震観測、木造住宅の破壊実験および理論解析的な観点から以下のような研究を行った。 1)神戸市長田区や芦屋市などの地域において、観測された地盤常時微動データと余震記録を用いて地盤構造、特に沖積層との関連から地震動を推定し、これらの地域で木造建物の被害率との関係を明らかにした。 2)神戸市東灘区の木造建物約2000棟の全数調査と阪神地域全体にわたる185棟の詳細調査に基づき、建築年代や建築規模の影響を考慮した木造建物の耐震性能を評価した。 3)木造建物の動力学特性は不確定性を有するため、建物用途、規模、建設年代の異なる既存木造建物を対象として常時微動観測を行い、また実在の建物を対象として自由震動実験および破壊実験を実施し、木造建物の復元力特性や動力学特性を評価した。次いで、木造建物の動力学モデルを構成し、地震応答解析を介して被害シミュレーションを行い、これより、建物崩壊のメカニズムを耐震性能を調べた。 5)木造建物の耐震性能を支配する壁や軸組などの構成要素の力学特性を捉えるとともに、木造軸組の補強法の開発と実験による検証を行った。 6)木造家屋被害の要因として、軸組構造部材の腐朽や蟻害が見られ、構造部材の耐力を劣化させたことから、木造家屋の壁体内および床下湿度の変動に関する長期測定等の調査研究から防止対策を計った。 7)既存の木造建物の多くが、伝統的在来構法の木造住宅であるので、地域特有伝統構法の取り上げ、その構法詳細および平面・立体形態を調べ、建築構法・建築計画の側面から木造住宅の耐震性について検討を行った。
  • 日本学術振興会:科学研究費助成事業
    Date (from‐to) : 1995 -1995 
    Author : 村上 雅英
     
    はり主筋の機械式定着の設計法を確立するために、4体のト型柱はり試験体の部材実験を行うと共に、既に申請者が行った92体の部材試験結果と他機関で行われた既往の実験結果に基づいて、以下の知見を得た。 ・柱の側面被りコンクリート厚さが薄く、定着筋1本当たりの作用引っ張り力が大きい時は、被りコンクリートが割裂ひび割れによって面外に剥離する破壊となる。一般にこの破壊を「定着破壊」と呼んでおり、折り曲げ定着でも見られる。しかし、機械式定着の定着耐力は、ほぼ同じ条件の90度折り曲げ定着の場合よりもはるかに高い定着耐力を有することが一連の引き抜き試験より明らかとなった。そして、申請者らはそれら一連の実験結果より、機械式定着の定着終局強度推定式の妥当性を確認した。 ・定着長さが柱成の1/2で定着破壊が生じない時は、定着部のコンクリートが掻き出される「掻き出し破壊」となるが、その最大耐力は折り曲げ定着の場合よりも低い。 ・定着長さが柱成の3/4で定着破壊が生じない時は、接合部のせん断破壊ろなる。 ・はり曲げ降伏時の接合部入力せん断力に対する接合部せん断強度の余裕度と定着破壊の関係を実験的に調べた。その結果、はり曲げ降伏時の接合部のせん断応力度が接合部のせん断強度の80%以下の場合、部材角が1/25rad.までは、折り曲げ定着と機械式定着は共にはりの曲げ降伏による紡錘型の復元力特性を表し、その後は共に定着破壊を起こした。 ・機械式定着と等価な折り曲げ定着の場合の比較実験より、両者の定着耐力の発現機構の相違を実験的に明らかにした。 ・既往の実験結果に基づいて、現行の1次設計に対応する許容応力度設計法を確立した。
  • 日本学術振興会:科学研究費助成事業
    Date (from‐to) : 1994 -1994 
    Author : 村上 雅英
     
    低測圧3軸圧縮応力下におけるプレーンコンクリートの最大強度以後の破壊現象を解明するために、2次元的な破壊パターンが得られる3軸圧縮試験装置を開発した。そして、粗骨材の最大寸法、コンクリート強度、試験体形状を実験変数として、合計、193体の3軸圧縮試験を行った。Mohr-Coulombの破壊基準が粗骨材間のブリッジ効果による応力伝達機構モデルを用いて説明できることを示した。残留強度基準を定式化し、最大強度時と残留強度時では、強度発現機構が異なることを示した。ひび割れ角度を定量的に計測し、それが残留強度基準の摩擦係数で近似できることを、実験的に示した。また、エポキシ樹脂注入によってひび割れを可視化することにより、ひび割れを性状を詳細に観察するとともに、画像処理によって不連続付近の損傷程度とその領域を定量的に評価し、以下の知見を得た。 ○Mohr-Coulombの破壊基準と粗骨材間のブリッジ効果による強度発現機構が等価であることを示した。それによって、Mohr-Coulombの破壊基準においても1軸圧縮における割裂破壊の説明が可能となった。 ○最大強度基準と残留強度基準を定式化した。また、粗骨材の最大寸法、コンクリート強度が、それらの各係数に与える影響を、粗骨材間のブリッジ効果モデルを用いて定性的に説明した。 ○側圧がS_1=0〜-6MPaの範囲では、不連続面付近の損傷範囲の側圧の大きさによる拡大は少ない。しかし、側圧の増大により不連続面付近のモルタルクラックの密度が増大する。 ○損傷領域の範囲は不連続面に対し片側についてほぼ粗骨材の最大寸法G_であり、不連続面が±0.5G_で蛇行すると仮定した場合、損傷領域の幅は3G_となる。
  • 在来木造住宅の耐震性に関する研究
  • Study on seismic performance of traditional wooden houses

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