Load Duration and Seasoning Effects on Mortise & Tennon Joinery

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upture. Bearing failure of the peg, mortise or tenon could also control the joint design, but such bearing failures have not been observed. 2.2. Test Frame Set-up In order to find the minimum end, edge <strong>and</strong> spacing requirements, full-scale joint tests were performed on mortise <strong>and</strong> tenon joints constructed from eastern white pine. The test frame was the same as was used in previous research (Schmidt <strong>and</strong> MacKay, 1997). The test set up consists of an “A” frame with an Enerpac RCH 123 hydraulic ram, which applies a tensile force to the tenon member; see Figure 2-2. The base of the frame restrains motion of the mortise piece. Two 2” linear potentiometers record joint displacement. The potentiometers are attached to the tenon member with the tip resting on the mortise member. Labview data acquisition software was used to record <strong>and</strong> average the two potentiometer readings. Readings from a pressure transducer were recorded <strong>and</strong> combined with the potentiometer readings to plot load verses deflection. The load-deflection plot was used during the test to determine when the joint was yielding <strong>and</strong> when the test could be stopped. 11
Figure 2-2 Short Term Test Set-up from Schmidt <strong>and</strong> MacKay (1997) 2.3. Short Term Test Procedure The short term monotonic test procedure was modeled after research conducted by Schmidt <strong>and</strong> Daniels (1999). Timber frame members for each joint were r<strong>and</strong>omly selected <strong>and</strong> checked for defects. The joint was lightly clamped together to assure a secure fit. Two peg holes were then drilled at a location that was thought to the minimum end <strong>and</strong> edge distance required to achieve peg failure. Two pegs were r<strong>and</strong>omly selected out of the same population used by Schmidt <strong>and</strong> Daniels for their joint tests. The pegs were oriented tangentially, with growth rings in the same direction as applied force. The pegs were then driven with a mallet until secure. The joint was placed into the test frame <strong>and</strong> the two linear potentiometers were fastened to the tenon with wood screws. A troubleshooting Labview data acquisition program was run to check for data acquisition errors. If no errors were detected, the program used for testing was started. Start time then was recorded <strong>and</strong> loading began. 12
Page 1 and 2: LOAD DURATION AND SEASONING EFFECTS
Page 3 and 4: Acknowledgments This report is base
Page 5 and 6: 5.5.1. Joint Properties ...........
Page 7 and 8: List of Tables Page Table 2-1 Easte
Page 9 and 10: ugged traditional style has helped
Page 11 and 12: 1.3. Literature Review Previous res
Page 13 and 14: However these failures were away fr
Page 15 and 16: 1.5. Overview Primary among the thr
Page 17: 2. Joint Tests (Eastern White Pine)
Page 21 and 22: Figure 2-3 Typical Mortise Member F
Page 23 and 24: offset horizontally a distance of 5
Page 25 and 26: 2.7. Dowel Bearing Strength Dowel b
Page 27 and 28: 2.8. Detailing Requirements (End/Ed
Page 29 and 30: Figure 2-9 Illustration of Peg Fail
Page 31 and 32: properties of a base material loade
Page 33 and 34: ut the load is applied through the
Page 35 and 36: Table 3-2 Spring Theory Summary Tes
Page 37 and 38: the stiffer of the two materials; r
Page 39 and 40: 4. Long Term Seasoning</str
Page 41 and 42: of the calibration markings were ob
Page 43 and 44: appropriate location for the center
Page 45 and 46: Table 4-1 Douglas Fir Long-Term Joi
Page 47 and 48: Normalized Douglas Fir 0.25 0.20 1.
Page 49 and 50: 4.2.3. Results and
Page 51 and 52: 4.3. Southern Yellow Pine Twenty-on
Page 53 and 54: Southern Yellow Pine 0.160 Deflecti
Page 55 and 56: Southern Yellow Pine Moisture Conte
Page 57 and 58: Normalized Southern Yellow Pine 0.0
Page 59 and 60: 2.0D end distance and</stro
Page 61 and 62: two pegs was active in carrying the
Page 63 and 64: Normalized White Oak 0.25 0.20 Defl
Page 65 and 66: White Oak 40 35 30 Moisture Content
Page 67 and 68: loaded to 1000 lb which is 16% of t
Page 69 and 70:
with only one joint it is difficult
Page 71 and 72:
4.5.2. Moisture Content The eastern
Page 73 and 74:
Eastern White Pine 0.30 0.25 0.20 D
Page 75 and 76:
5. Failure Testing of Long Term Spe
Page 77 and 78:
earing test samples were oriented i
Page 79 and 80:
5.3.2. Material Properties (Dowel B
Page 81 and 82:
twelve joints had white oak pegs <s
Page 83 and 84:
the load-deflection plots shown in
Page 85 and 86:
6.2. Modification to minimum end <s
Page 87 and 88:
unloaded. Therefore, the Madison Cu
Page 89 and 90:
7. References AFPA, (1997). “Nati
Page 91 and 92:
Load-Deflection Pl
Page 93 and 94:
Dowel Bearing Test Results Test Num
Page 95 and 96:
Peg Specific Gravity and</s
Page 97 and 98:
Load-Deflection Pl
Page 99 and 100:
SYP 35 SYP 36 9000 4000 3760.44 800
Page 101 and 102:
Specific Gravity and</stron
Page 103 and 104:
Appendix C (white oak) 7.1.1. Joint
Page 105 and 106:
WO 27 WO 28 7000 6000 6474.64 9000
Page 107 and 108:
WO 43 WO 44 12000 10000 16000 14000
Page 109 and 110:
Page 111 and 112:
Appendix D (eastern white pine) oin
Page 113 and 114:
EWP 27 EWP 28 12000 8000 7579.80 10
Page 115 and 116:
EWP 43 EWP 44 9000 8000 7000 5000 4
Page 117 and 118:
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Load Duration and Seasoning Effects on Mortise & Tennon Joinery

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