1991 Fiscal Year Final Research Report Summary
Strength of Folded Plate Structures with Shallow Angle and Its Realization for Practical Use
| Project/Area Number |
01850100
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| Research Category |
Grant-in-Aid for Developmental Scientific Research
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| Allocation Type | Single-year Grants |
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| Research Field |
土木構造
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| Research Institution | Tohoku University |
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Principal Investigator |
KURANISHI Shigeru Tohoku University, Dept. Civil Eng., Professor, 工学部, 教授 (70005221)
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| Co-Investigator(Kenkyū-buntansha) |
NAKAZAWA Masatoshi Tohoku University, Dept. Civil Eng., Research Associate, 工学部, 助手 (20198063)
IWAKUMA Tetsuo Tohoku University, Dept. Civil Eng., Associate Professor, 工学部, 助教授 (60120812)
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| Project Period (FY) |
1989 – 1991
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| Keywords | Folded-Plate Sturcture / Folded Angle / Plate Girder / Bending Strength / Shear Strength / Compressive Strength |
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| Research Abstract |
As a result of linear buckling analysis for the plate girder with folded web, it is found that the buckling strength is reasonably enhanced when the folded angle of 15 degrees is employed for bending, 5 degrees for compression. These are also confirmed by the experimental studies using the acryl material, and it is observed that these specimens show the stable behavior even for the post-buckling loading stage.
The ultimate strength analysis is carried out for this folded web girder under bending. The increase of load carrying capacity is confirmed in the case of more than 10 degrees of folded angle, and the ultimate strength is also obtained for variable aspect ratio and depth-thickness ratio of folded web panel, which turns out to be stable state with no abrupt reduction of strength.
The longitudinal stiffener of plate girder can be omitted, when the folded web of 15 degrees is employed considering the post-buckling behavior. The design recommendation can be described by the form of lim
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itation of depth-thickness ratio corresponding to the yield stress level of structural steels. The compressive strength design of folded plate is achieved by the present design method for sub-panels between the folded lines when more than 5 degrees of folded angle is maintained. However, it is necessary to conduct more experimental studies using the actual steel material not acryl to confirm the strength property and to present the design procedure in detail.
Finally, the technical problems to fabricate the folded plate are summarized. Since the precision of the folded angle is hardly obtained in the actual fabrication, the allowable range of folded angle must be set in the actual fabrication. Is is necessary to fold the panel in the smaller angle to avoid the spring back of folded angle. Therefore, the range of allowable curvature should be set by considering the thickness of plate, type of steel materials and magnitude of folded angle. Moreover, the influence of residual stresses of plate bending and in-plane components induced by the fold of plate must be investigated. Less
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