1998 Fiscal Year Final Research Report Summary
Study on enhancement in seismic performance of concrete piers by applying vertical prestressing
| Project/Area Number |
09305033
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| Research Category |
Grant-in-Aid for Scientific Research (A)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
構造工学・地震工学
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| Research Institution | Yokohama National University |
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Principal Investigator |
IKEDA Shoji Yokohama National University, Faculty of Eng., Professor, 工学部, 教授 (60087228)
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| Co-Investigator(Kenkyū-buntansha) |
YAMAGUCHI Takahiro Yokohama National University, Faculty of Eng., Asistant, 工学部, 助手 (10143736)
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| Project Period (FY) |
1997 – 1998
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| Keywords | Prestressed Concrete Pier / Vertical Prestressing / Seismic Performance / Hollow Cross Section / Eccentric Load |
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| Research Abstract |
In order to enhance seismic behavior of concrete piers by applying vertical prestressing, static and pseudo-dynamic tests using prestressed concrete column specimens were carried out. The main results obtained from this study are described as follows :
1. The prestressed concrete pier (PC pier) in which the prestressing tendons were unbonded had same ductility as an ordinary reinforced concrete pier when the total compressive stress due to the prestress and external axial stress was less than 25% of the concrete compressive strength. Also, it was shown that the PC pier had high restoration capability, and that the residual deformation was proportional to the sharing ratio of ordinary reinforcement in flexure.
2. The seismic performance of PC pier having hollow cross section were differed largely according to the shape of cross section at the column bottom. The pier which was designed considering the stiffness of the cross section at the column bottom in such a way that height of D (D : height of cross section) from footing surface was filled up with concrete or, in the case of D/2, additional reinforcing bars were arranged at the bottom showed sufficient seismic performance.
3. It was clarified that the PC pier could avoid the resonant behavior of vibration under seismic motion due to the fact that the natural period changed to longer side due to the cracking of concrete and yielding of reinforcement without yielding of PC tendons.
4. It can be expected that the PC pier has high restoration capability under eccentric condition as well as ordinary condition if vertical prestressing was adequately installed considering the eccentricity of the gravity.
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