TASAI Akira

Organization

Faculty of Urban Innovation, Department of Urban Innovation

Title

Professor

Research Fields, Keywords

Building Structure, Reinforced Concrete, Seismic Design, Seismic Rehabilitation



写真a

Graduating School 【 display / non-display

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    -
    1978.03

    The University of Tokyo   Faculty of Engineering   Graduated

Graduate School 【 display / non-display

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    The University of Tokyo  Graduate School, Division of Engineering    Unfinished course

External Career 【 display / non-display

  • 1995.04
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    2000.03

    Osaka Institute of Technology   Faculty of Engineering   Associate Professor (as old post name)  

  • 1982.04
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    1995.03

    University of Tokyo   Faculty of Engineering   Research Assistant  

Academic Society Affiliations 【 display / non-display

  • 1983.02
     
     
     

    Japan Concretet Institute

Field of expertise (Grants-in-aid for Scientific Research classification) 【 display / non-display

  • Building Structure

Qualification acquired 【 display / non-display

  • Architect (first class)

 

Research Career 【 display / non-display

  • Earthquake Resistance of Reinforced Concrete Structure

    Project Year:  -   

Books 【 display / non-display

  • AIJ Seismic Performance Evaluation Guidelines for Reinforced Concrete Buildings Based on th Capacity Spectrum Method

    (Part: Other )

    Architectural Institute of Japan  2019.03 ISBN: 978-4-8189-0649-5

Papers 【 display / non-display

  • Experimental study on exterior beam-column joint using mechanical anchorage for main bars with orthogonal beam

    Akira Tasai, Takumi Yamaguchi, Kotarou Yamamoto, Kuniyoshi Sugimoto, Toshihiko Kiyohara, Joji sakuta, Masahiro Chiba, Tomohiro Adachi

    Proceedings of the international conference on the 55th anniversary of establishment of Vietnam Institute For Building Science And Technology     187 - 193   2018.11  [Refereed]

    Joint Work

  • Nonlinear finite element analysis of RC wall column specimen using post-installed adhesive anchors for main bars

    Kuniyoshi Sugimoto, Akira Tasai, Ryoko Tani, Tomoaki Akiyama, Hiroshi Fukuyama, Yoshio Inoue

    Proceedings of the international conference on the 55th anniversary of establishment of Vietnam Institute For Building Science And Technology     257 - 263   2018.11  [Refereed]

    Joint Work

  • Experimental Study on the Outside Attached Seismic Strengthening Method Using Steel Panel Damper Part 8 Part 9

    AIJ Summaries of Technical Papers of Annual Meeting   構造Ⅳ   353 - 356   2018.09

    Joint Work

  • EXPERIMENTAL STUDY ON IN-PLANE SHEAR BEHAVIOR OF AAC BLOCK MASONRY WALLS WITHOUT OPENINGS

    TAKASHIMA Kenji, NAKAMURA Ryota, NAKATA Shinji, HANAI Tsutomu, SUGIMOTO Kuniyoshi, KUSUNOKI Koichi, TASAI Akira

    Journal of Structural and Construction Engineering (Transactions of AIJ) ( Architectural Institute of Japan )  ( 749 )   1075 - 1085   2018.07  [Refereed]

    Joint Work

     View Summary

    &nbsp;An Autoclaved aerated concrete (AAC) is an efficient structural material because its light weight reduces seismic inertia forces under earthquake excitations and improves thermal insulation quality for comfortable environments. Since an AAC panel structure can't be designed in Japan, we propose a reinforced and fully grouted AAC block masonry structure. Few experimental studies of bearing wall constructed of non-reinforced AAC blocks are available. In this study, in-plane tests of bearing walls constructed of reinforced AAC blocks with internal bars and the non-reinforced AAC blocks were carried out and the effect of the internal bars is confirmed. Furthermore, the strength and deformation calculated referring to previous studies in concrete block masonry structures were compared with test results.<br>&nbsp;Three types of AAC blocks (ALC50, ALC37 and ALC42) which have different specific gravity and the internal bars or not constitutes the masonry wall. ALC50 and ALC37 have the internal bars and ALC42 doesn't have them. Each AAC block has grooves and vertical holes. Vertical reinforcements are cast in the holes and horizontal re-bars are cast in the grooves. After the blocks are pasted with sealant and built, the grooves and holes were fully grouted in order to achieve a good bonding behavior between the reinforcements and the blocks. Each mechanical property of the materials is shown in Table 2.<br>&nbsp;Compression and shear wallette tests were carried out and those mechanical properties and those failure behaviors were obtained. The test specimens with the internal bars avoided the sharp post-peak drop and enhanced displacement capacity. Therefore, it is considered that the internal bars provide confinement under the compressive force and shear reinforcing effect under the shear force.<br>&nbsp;In-plane tests of masonry bearing walls without openings were carried out. A suite of five specimens which have different block type and wall length (aspect ratio of 0.7 to 3) was tested by using a test setup of cantilever system. In the test results, a bed joint separation, a flexural crack, a shear crack and yielding of vertical bar were confirmed and integrated wall behaviors were observed until peak load. Flexural failure mode or shear failure mode after yielding was observed. The shear failure mode after yielding was observed in the specimen of few horizontal reinforcing bars or low aspect ratio or built with the non-reinforced blocks.<br>&nbsp;Based on the mechanical properties obtained from compression and shear wallette tests, strength and deformation were calculated referring to previous studies in masonry structures. The flexural strength and the flexural deformation were calculated with the equation of simple bending theory. The shear strength was calculated with equation of concrete block masonry structures and the shear deformation was calculated with equation of theory of elasticity. The calculation results of the strength are almost good agreement with the test results. The calculation results of the deformation are a little lower than the test results because an effect of shear crack for shear deformation was not considered<br>&nbsp;In the case of structural design for this AAC masonry structure, we propose to take into more consideration for safety because of a limited number of experimental tests in this study.

    DOI CiNii

  • HYSTERETIC RESTORING FORCE CHARACTERISTICS OF RC WALL COLUMN SPECIMEN USING POST-INSTALLED ADHESIVE ANCHORS FOR MAIN BARS

    SUGIMOTO Kuniyoshi, TASAI Akira, TANI Ryoko, AKIYAMA Tomoaki, FUKUYAMA Hiroshi, INOUE Yoshio

    Journal of Structural and Construction Engineering (Transactions of AIJ) ( Architectural Institute of Japan )  ( 749 )   1041 - 1050   2018.07

    Joint Work

     View Summary

    &nbsp;<b>1. Introduction</b><br>&nbsp;This paper describes investigation about hysteretic restoring force characteristics of reinforced concrete wall column specimens. Static loading tests of three specimens were conducted. Nonlinear finite element analysis were conducted for three specimens. The objective in this paper is to investigate effect of bond behavior of post-installed adhesive anchors on restoring force characteristics.<br>&nbsp;<b>2. Outline of the Static Loading Tests</b><br>&nbsp;Three specimens were tested. One of them, WS485, was ordinal reinforced concrete specimen, while in the other specimens, post-installed adhesive anchors were used for main bar anchorages. The difference between the other two specimens was anchor length of main bars. One of them, the specimen named as WA485 had the same length as the RC specimen WS485. The other post-installed adhesive anchor specimen, named as WA265 had shorter length of anchorage than the other two specimens. As the test results, yielding of the main bars were observed for all specimens and three specimens had almost same capacities. Slip behaviors were observed in WA265 and WS485, and energy dissipation capacity of specimen WA265 was lower than those of the other specimens.<br>&nbsp;<b>3. Modeling for Nonlinear Finite Element Analysis</b><br>&nbsp;Three-dimensional nonlinear finite element analyses were conducted using &ldquo;FINAL&rdquo;. Concrete was modelled using eight-node hexahedral element and main bar was modelled using truss element. Four-node joint type elements were inserted between hexahedral elements and truss elements of main bars for the purpose of incorporating bond slip behavior. For the specimens WA485 and WA265, the perimeter length of post-installed adhesive anchor was calculated from the diameter of drill instead of main bar.<br>&nbsp;<b>4. Comparisons of Analytical and Experimental Results</b><br>&nbsp;Crack patterns were shown in Figure 5, and load-displacement relationships were compared in Figure 6. Horizontal cracks along the main bars in stub were observed in both experimental and analytical results. Slip behavior in load-displacement relationship for the specimen WA265 and WS485 obtained from the analyses were observed similar to the experimental results. Although the equivalent viscous damping ratios of analytical results for specimen WS485 and WA485 were slightly underestimated to the experimental results, analytical results for the specimen WA265 showed good accordance with experimental ones. Load and flexural, or shear, displacement relations were shown in Figure 11. Fig. 11 shows that the slip behavior was observed in flexural mode. Figure 12 shows the stress distribution of main bars for both analytical and experimental results. Although the analytical results in tension corresponded well to the experimental ones, analyses underestimated in compression.<br>&nbsp;<b>5. Conclusion</b><br>&nbsp;Restoring force characteristics of RC wall column specimens were investigated both experimentally and analytically. Three types of main bar anchorage were investigated. One was ordinal type, while the other two were post-installed adhesive anchors. Anchor length was varied in the latter two specimens. The specimen WA265, which had shorter length anchorage showed lower energy dissipation characteristics than the other two specimens and slip behavior was observed. Analytically, these behaviors were shown with good accordance with the experimental results. Stress distribution of main bars derived from analytical results corresponded well to the experimental ones only in tension.<br>&nbsp;<b>Acknowledgement</b><br>&nbsp;Static loading tests were conducted through the project: &ldquo;study on confirmation methods of structural performances for RC members using post-installed adhesive anchors&rdquo;, which was supported by the subsidies for the project servicing the architectural standard from the Ministry of Land, Infrastructure, Transport and Tourist.

    DOI CiNii

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Review Papers 【 display / non-display

  • Structural Performance of Reinforced Concrete Beam with Secondary Walls Having Structural Gaps

        2016.08  [Refereed]  [Invited]

    Introduction and explanation (others)   Single Work

Works 【 display / non-display

  • Damage Investigation by 1993 Kushiro-oki Earthquake

    Other 

    1993
     
     
     

  • Investigation of Damage from the 1987 Iwateken-chubu Earthquake

    Other 

    1987
     
     
     

  • Investigation of Damage from the 1983 Nihonkai-chubu Earthquake

    Other 

    1983