1998 Fiscal Year Final Research Report Summary
Research on Damage Estimation of R/C Interior Beam-Column Joints and Effect of Bond Behavior of Beam Bars within Joint
| Project/Area Number |
08650660
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Building structures/materials
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| Research Institution | HOKKAIDO UNIVERSITY |
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Principal Investigator |
GOTO Yasuaki Grad.School of Eng., Hokkaido Univ., Assoc.Prof., 大学院・工学研究科, 助教授 (90170472)
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| Project Period (FY) |
1996 – 1998
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| Keywords | reinforced concrete / beam-column joint / bond condition / shear failure / double layered bars / loading history / finite element method |
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| Research Abstract |
Toward the rational requirement of RC beam-column joints, both experimental and analytical studies were carried out. Followings were obtained.
1) Experimental data on RC interior beam-column joint in plane and space frame was collected and analyzed.
2) Two experimental studies were carried out.
Plane frame test : To examine the effect of joint shear input and beam bar condition on frame behavior, 6 half size specimens were tested, which had differences in beam bar area (2 variations) and bar diameter (3 variations). Beam yielding was observed in all specimens. Joint shear failure occurred in all specimens of large shear input in joint at large displacement, but even in a specimen of low shear input. 3-dimensional frame test : To examine the effect of transverse beams and loading history on joint performance, 4 half size specimens were tested which had difference in joint input (beam bar area : 2 variations) and bond condition (diameter : 2 variations) and also had slabs. 2 specimens were the same in both bar area and diameter, but different in loading history. All specimens were loaded cyclically with gradually increment in displacement. 3 specimens were loaded one way and perpendicular alternately in the same displacement, but one specimen was loaded only one way till ultimate stage and then perpendicular.
Following conclusions are derived from two experimental studies :
i) Beam bar condition in joint did not make a large influence in energy dissipation of frame, if joint shear failure occurred after beam yielding.
ii) Joint shear strength was increased by the existence of transverse beams.
iii) The damage of joint core concrete in one way loading made weak in frame performance in perpendicular loading.
3) 2-dimensional non-linear finite element analysis on RC interior beam-column joint showed that joint compressive concrete strut became steeper if beam bar bond condition was inferior.
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