2000 Fiscal Year Final Research Report Summary
Study on Development of Steel-Free Concrete Deck Slabs
| Project/Area Number |
11555114
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| Research Category |
Grant-in-Aid for Scientific Research (B).
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| Allocation Type | Single-year Grants |
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| Section | 展開研究 |
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| Research Field |
土木材料・力学一般
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| Research Institution | Akita University |
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Principal Investigator |
KAWAKAMI Makoto Akita University Faculty of Engineering and Resource Science Professor, 工学資源学部, 教授 (90006693)
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| Co-Investigator(Kenkyū-buntansha) |
YOSHIOKA Tamio Oriental Construction Co. Ltd. Research Laboratory Director, 技術研究所, 所長(研究職)
TOKUSHIGE Hidenobu Akita University Faculty of Engineering and Resource Science Lecturer, 工学資源学部, 講師 (80291269)
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| Project Period (FY) |
1999 – 2000
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| Keywords | steel-free slab / arch action / unboded prestressing / punching shear / crack / ultimate strength / high strength concrete |
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| Research Abstract |
(1)First series of loading tests for steel-free slabs were carried out to clarify ultimate strength and deflection. In these tests, the thickness and width of steel plate used to confine the concrete slabs were considered as variable parameter. From these tests results, the increase of confinement ratio has drastically influenced the change of failure mode from bending to shear failure. However higher confinement ratios than 2% have not increased the strength significantly.
(2)Effect of the end supports condition and prestressing on the flexural behavior of steel-free slab by undergoing an experimental and theoretical study on a simple supported and fixed slabs in both prestressed and non-prestressed cases were investigated. The results obtained from the second series of tests can be summarized as follows ; 1)End support confinement is efficient in restraining the steel-free slabs before cracking, but it is not reliable after cracking. 2)External prestressing is effective in increasing both cracking and ultimate loads.
(3)Third series of load tests are punching tests on six full scale steel-free slabs transversely prestressed with unbonded external bars. The obtained results showed that unbonded prestressing and concrete strength increased the ultimate punching load to some extent but no considerable effect on increasing the cracking load was obtained. Prestressing proved efficiency in controlling cracks development, which means a great improvement on the serviceability of the slab.
(4)All results of two years from 1999 to 2001 were summarized and the report was completed.
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