Load Duration and Seasoning Effects on Mortise & Tennon Joinery

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Figure 3-2 Base Material Dowel Bearing Test (From Schmidt <strong>and</strong> Daniels 1999) A peg bearing test is the second type of test used. A peg bearing test uses a 1-1/2” square steel load block with a 1” diameter half circle in one face. The peg is placed into a long shallow trough cut into a steel base plate with the ends of the peg clamped to the base plate to hold the peg flat during the test. The load block is placed on top of the peg. <strong>Load</strong> is applied to the load block to test the peg bearing strength (see Figure 3-3 below). Figure 3-3 Peg Dowel Bearing Test (From Schmidt <strong>and</strong> Daniels 1999) The third test involves a combination of the eastern white pine base material block <strong>and</strong> a white oak peg. The peg is secured in the trough of the base plate as in Figure 3-3, 25
ut the load is applied through the base material block. The shallow trough prevents bearing failure of the peg remote from the interface between the peg <strong>and</strong> the base material. The test is similar to that shown in Figure 3-3 with the base material in place of the steel load block. 3.3. Method <strong>and</strong> Results <strong>Load</strong>-deflection results of base material bearing <strong>and</strong> peg bearing tests were processed by a program that performed a filtering operation on the load-displacement curve. The program smoothed the test data into uniform load increments of 25 pounds <strong>and</strong> found the corresponding displacement. The displacements of the two tests at the same load were then added in order to synthesize a load-displacement curve for the combined materials. The 5% offset method with a 1” peg diameter was once again used for all of the tests in question. In order to reduce variability <strong>and</strong> to achieve a higher degree of confidence, matched bearing samples were cut from each piece of eastern white pine. Four bearing samples were cut from each tenon member <strong>and</strong> each mortise member. Two of the four samples were used for the conventional dowel bearing tests (Figure 3-2) <strong>and</strong> two for combined tests. To obtain matched specimens for the pegs, two-foot long pegs were cut in half so that one half of the peg could be used in the peg bearing test (Figure 3-3) <strong>and</strong> the other half in the combined test. A test specimen distribution table is given in Table 3-1. 26
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 and 18: 2. Joint Tests (Eastern White Pine)
Page 19 and 20: Figure 2-2 Short Term Test Set-up f
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: properties of a base material loade
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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