Timber Frame Tension Joinery - Timber Frame Engineering Council

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D D Im Is P = (3-41) t F m em P = (3-42) 2 tF s es 2 3 D IIIs = positive root of following equation: (3-43) ( + R ) ⎛ 21 Fyb ( 2 + Re ) FemD + ⎜ ⎝ R ⎞ 2 P 1 P 2 − 1 ⎟ ts Fem D + ( 2+ Re) tsFemD− ⎛ ( 2 Re) 0 ⎠ n 4 ⎝ ⎜ ⎞ ⎟ + = n ⎠ 4 e 2 2 2 e D IV = P 2n ( + R ) 31 2F F em e yb (3-44) D V = 2P nπF t v⊥ m (3-45) Where R e is now the ratio of the dowel bearing stresses (F em /F es ), for the bolted connection and F yb and F v are the bolt bending and yield stresses, respectively. Mode VI has been excluded from this analysis for bolt diameter because the shear yield stress in the main member will not change between a wood peg and a steel bolt, and the bolt diameter will only increase due to the end distance. For instance, if a connection is sized based on the shear in the peg, then the end distance is not a concern. When an equivalent steel bolt is determined using this mode, it will be much larger than the wood peg, due to the fact that less end distance is needed to balance out the load. From these equations, the largest diameter (D) is used as the equivalent bolt diameter. The following example (Figure 3-12) shows how a wood connection, with a yield load of 5,184 lb using two 1” Red Oak pegs, can carry an equivalent load using a 0.53” diameter steel bolt. 25
Using the equivalent bolt diameter, the end distance can be determined from the NDS requirements. The end distance requirement of 7D, suggests that for a bolt that is 0.53” in diameter, an end distance of 3.71” is needed. For the equivalent 1” Red Oak peg, the same end distance of 3.71” should be adequate to develop the full load of the connection. There is also the possibility that another yield mode, similar to Mode III s is needed. In failed mortise and tenon connections, a common failure mode is one that contains a Connection Geometry D = 1.00 in (25 mm) t m = 2.00 in (51 mm) n = 2 t s = 1.75 in (44 mm) l v = 3.00 in (76 mm) Wood Peg Properties Steel Bolt Properties F yb = 12,600 psi (86.9 MPa) F yb = 45,000 psi (310.3 MPa) F v ⊥ = 1,650 psi (11.4 MPa) F v ⊥ = 27,000 psi (186.2 MPa) F em = 1,547 psi (10.7 MPa) F em = 4,050 psi (27.9 MPa) F es = 930 psi (6.4 MPa) F es = 1,950 psi (13.4 MPa) F vm = 280 psi (1.9 MPa) F vm = 280 psi (1.9 MPa) Based on Red Oak Pegs and Eastern White Pine Mortise and Tenon Load Analysis Equivalent Steel Bolt Analysis P Im = 6,188 lb (27.53 kN) D Im = 0.32 in (8 mm) P Is = 6,510 lb (28.96 kN) D Is = 0.38 in (10 mm) P IIIs = 6,249 lb (27.80 kN) D IIIs = 0.53 in (14 mm) P IV = 8,835 lb (39.30 kN) D IV = 0.45 in (12 mm) P V = 5,184 lb (23.06 kN) D V = 0.17 in (4 mm) P VI = 6,720 lb (29.89 kN) P = 5,184 lb (23.06 kN) D = 0.53 in (14 mm) Figure 3-12 Equivalent Bolt Diameter Example 26
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: need to know the required load and
Page 43 and 44: 4. Peg Testing Procedures and Analy
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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