Timber Frame Tension Joinery - Timber Frame Engineering Council

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single hinge in the peg, at the center of the tenon. In Mode III s the ends of the peg rotate through the side material and two hinges form, but this mode does not allow those two hinges to form at the same location (thus actually being one hinge) (see Figure 3-13). Mode III s is based on a single shear condition, where one end of the peg is held securely in the material of the main member. As the connection is loaded, the peg rotates through the side material and a hinge forms in the peg (see Figure 3-14). A mathematical model that properly reflects the strength of the peg and the surrounding material is necessary for Mode III s ’. Figure 3-13 Proposed Mode III s ' Figure 3-14 Mode III s (Single Shear) 27
4. Peg Testing Procedures and Analysis 4.1 General Testing Procedures for Hardwood Pegs This section introduces the tests performed by this researcher and the procedures followed for all tests. Testing procedures that are unique to the specific type of test are discussed in the section for that individual test. The tests performed were dowel bending tests, dowel bearing tests, dowel shear tests, and full-sized tests. The yield models require material properties specific to hardwood pegs. These properties include the bending strength of the pegs, the dowel bearing strength of the pegs in the main and side members, and the combined shear and bending strength of the pegs. Whenever possible, ASTM test procedures were followed. The primary species selected for peg testing were Red Oak and White Oak, with some additional testing of Locust, Birch, Maple, and Ash. The pegs were in diameters of ¾”, 1” and 1¼” and ranged in length from 8” to 12”. For the dowel bearing tests, the base materials were Douglas Fir, Red Oak, and Eastern White Pine. The samples were cut from 8x8 timbers roughly 4 feet in length. The pegs and base materials arrived approximately one year before this writing from various locations around the United States. They were placed in an environmental chamber, as per the ASTM standard D4933-91 for Moisture Conditioning of Wood and Wood-Base Materials, and kept at or near a temperature of 70° F and 65% relative humidity until they were needed for testing (ASTM, 1995a). The purpose for this was to condition the wood at a constant moisture content of 12%. Even though constancy would have been ideal, some fluctuations did occur due to seasonal effects and some mechanical breakdowns. The moisture content was determined for each test sample as required by ASTM D4442-92 (ASTM, 1995a). 28
Page 1 and 2: TIMBER FRAME TENSION JOINERY Richar
Page 3 and 4: Acknowledgments Acknowledgments go
Page 5 and 6: 5.4 Dowel Bearing Test Results.....
Page 7 and 8: List of Figures Page Figure 1-1 Typ
Page 9 and 10: List of Appendices Page Appendix A
Page 11 and 12: elasto-plastic behavior an ideal yi
Page 13 and 14: normal distribution orthotropic mat
Page 15 and 16: xiii
Page 17 and 18: Tie Beam Figure 1-2 American Timber
Page 19 and 20: 2. Timber Framing Background 2.1 Hi
Page 21 and 22: territories. Using the new construc
Page 23 and 24: Although timber framing is still a
Page 25 and 26: 3. European Yield Model and Propose
Page 27 and 28: strength, then the dowel could bend
Page 29 and 30: P III s = k3 ⋅D⋅ts ⋅F ( 2 + R
Page 31 and 32: The areas under the shear diagram c
Page 33 and 34: and F es = 1728 psi) (see Sections
Page 35 and 36: Figure 3-7 Combined Shear - Bending
Page 37 and 38: 3.5 Additional Yield Model Equation
Page 39 and 40: need to know the required load and
Page 41: Using the equivalent bolt diameter,
Page 45 and 46: dowel diameter and the intercept of
Page 47 and 48: were taken for two orientations (e.
Page 49 and 50: affected by the deformation in the
Page 51 and 52: Figure 4-6 Orientation of Prelimina
Page 53 and 54: The main purpose of the full-size t
Page 55 and 56: 5. Test Results 5.1 Introduction Th
Page 57 and 58: Table 5-1 Bending Test Correlation
Page 59 and 60: Table 5-4 Bending Yield Strength Re
Page 61 and 62: 5.3 Shear Test Results 181 shear te
Page 63 and 64: 0.90 0.90 Specific Gravity 0.80 0.7
Page 65 and 66: Yield Stress τ (psi.) 3/4" Red Oak
Page 67 and 68: 5.4 Dowel Bearing Test Results The
Page 69 and 70: obtained from shear tests at variou
Page 71 and 72: To obtain allowable stress design v
Page 73 and 74: l e l v Figure 6-1 Full-size Test D
Page 75 and 76: each mode in the general yield mode
Page 77 and 78: 7. Conclusions and Recommendations
Page 79 and 80: Appendix A Derivation of Dowel Rota
Page 81 and 82: Appendix C NDS Yield Mode II, Alter
Page 83 and 84: Appendix D NDS Mode III s , Alterna
Page 86 and 87: Appendix E Standard Test Setup for
Page 88 and 89: Appendix G Bending Test Data Summar
Page 90 and 91: Summary of Bending Tests: Last Revi
Page 92 and 93:
Appendix H Shear Test Data Summary
Page 94 and 95:
Summary of 1-1/4" Red Oak Shear Tes
Page 96 and 97:
Summary of 1" White Oak Shear Tests
Page 98 and 99:
Appendix I Dowel Bearing Data Summa
Page 100 and 101:
Bibliography Abe M., and Kawaguchi,
Page 102:
Soltis, L. A.; Karnasudirdja, S.; L
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