1998 Fiscal Year Final Research Report Summary
Effective Resistance of Timber Joints with Multiple Fastenings due to their Lead Hole Clearances
| Project/Area Number |
09660172
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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 |
林産学
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| Research Institution | HOKKAIDO UNIVERSITY |
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Principal Investigator |
HIRAI Takuro Fac.of Agr.Hokkaido Univ.Prof., 農学部, 教授 (20173205)
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| Project Period (FY) |
1997 – 1998
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| Keywords | Drift-pin / Moment-resisting joint / Lead hole clearance / Lateral resistance / End / side margin / Spacing / Monte Carlo simulation |
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| Research Abstract |
First we conducted an experimental study on effective moment resistance of drift-pinned joints with lead hole clearances. We prepared test specimens with two kinds of lead hole clearance (1 and 2mm), two kinds of drift-pin number (4 and 8 drift-pins), and two kinds of length/diameter ratio of drift-pins (6 and 12). Destructive tests of them showed : 1.Centers of rotation of the joints were irregular due to the initial conditions of each drift-pin and they traveled through the loading. 2.The drift-pins with larger length/diameter ratio gave greater maximum resistance of the joints. 3.Spacing between the fastenings gave a obvious effect on the maximum resistance, so that the joints assembled with fewer drift-pins which were arranged with enough spaces had greater maximum resistance.
Next we simulated the effective moment resistance of the drift-pinned joints by the Monte Carlo method. Basic data required for the simulation were obtained from the destructive double-shear tests with single drift-pins. Preceding the Monte Carlo simulation, ideal moment-rotation relationship of the joints was analyzed definitely assuming that all drift-pins bore evenly the applied moment An arbitrary assumption that a couple of drift-pins diagonal to each other had the same initial gap along their slip directions was adopted in the Monte Carlo simulation, because anisotropic strength properties of timber joints and indetermination of load distribution among the fastenings made the strict simulations too difficult Major conclusions were : 1 .Effective stiffness of the joints with lead hole clearances were able to be estimated by the Monte Carlo simulation. 2.The definite analysis assuming the initial gaps of 50 percent to the clearance also gave practically appropriate estimation. 3.End/side margins and spacing had great effects on the maximum resistance, which made the prediction of the effective maximum resistance very difficult.
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