1987 Fiscal Year Final Research Report Summary
Study on Ultimate Shear Strength and Shear Design Equation for the Spirally Reinforced Concrete Columns
| Project/Area Number |
61550400
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
Building structures/materials
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| Research Institution | Muroran Institute of Technology |
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Principal Investigator |
ARAKAWA Takashi Muroran Institute of Technology ・ Professor, 工学部, 教授 (90002815)
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| Co-Investigator(Kenkyū-buntansha) |
MIZOGUCHI Mitsuo M. I. T.・ Assistant, 工学部, 助手 (80166040)
ARAI Yasuyuki M. I. T. ・ Assistant Professor, 工学部, 助教授 (80002210)
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| Project Period (FY) |
1986 – 1987
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| Keywords | Spiral hoop / Reinforced concrete column / Shear strength / Shear reinforcement / Axial load / 剪断設計式 |
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| Research Abstract |
The purpose of this study is to clarify the following items, according to the cyclic loading tests on 28 (divided into 2 series in each 14, scale is about 1/3 of full-size) column specimens with spiral hoops.
1) To determine quantitatively certain factors' influences on the ultimate shear strength of reinforced concrete octagonal columns with spiral hoops.
2) To review the suitability of the experimental equations and several countries' code equations for shear strength of reinforced concrete columns based on the recent test date.
The results are summarized as follows:
(1) the phenomena of cracking and shear failure for the octagonal columns with spiral hoops are similar to those of the normal columns with square hoops.
(2) The ultimate shear strength of the spirally reinforced concrete columns increased with the increasing of concrete strength (Fc), axial load (N), spiral reinforcement ratio and longitudinal reinforcement ratio. The ultimate shear strength decreased with the increasing of
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column height. These strengths are similar to those of square columns.
(3) The shear strength of octagonal columns can be calculated conservatively using the existing shear strength equations by replacing the octagonal sections with squares having the same gross area and same reinforcement.
(4) The test results indicate that the shear carried by truss mechanism involving spiral reinforcement (Qut) is well represented by the 45゜ truss model and the remainder shear can be expressed by the (1+<eta>_0) times ofthe shear carried by arch mechanism (Qua). Where <wta>_0 is the axial compressive stress factor (=N/A・Fc, A is the cross-sectional area of column). The shear strength equation for reinforced concrete columns, Qu(=Qut+Qua), is as the same as the B method, which is the one now under consideration for a new shear design equation in the Architectural Institute of Japan.
(5) The current empirical equations and several countries' code equations for shear strength are investigated according to 118 available date of the most recent experiments. As mentioned in (4), the modified shear design equation of the AIJ [Qu=Qut+(1+<eta>_0)Qua] is in better agreement with test date. Less
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Research Products
(12 results)
