roof framing connections in conventional residential construction

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Figure 12Horizontal Movement of Truss(in initial position truss was aligned with stud)Figure 13Wood Tear Out and Plate Bendingon Tension Side of ConnectionFigure 14Truss Plate SeparationFigure 15No Visual Damage on CompressionSide of ConnectionFigures 16 and 17 show the failure modes for test specimens 3 and 4. In addition to the failuremodes associated with specimens 1 and 2, the withdrawal of shorter 8d common nails from thewall top plate was observed. The nail withdrawal also caused uplift deformations of trusses fromthe wall top plate (Figure 16).32
Figure 16Truss Separation from Top Platedue to Nail WithdrawalFigure 17Wood Tear Out and Plate Bendingon Tension Side of ConnectionThe location of the truss plates in the heel joint assembly directly above the supporting walllimits the available surface for installation of nails and other connectors. In this test program, thenails were installed into the bottom chord member in the region between the truss plate andexterior surface of the wall (Figure 16). The nail location near the beveled end of the trussbottom chord precipitated the premature wood splitting and tear-out failure. The installation oftoe-nails through the metal truss plates, as sometimes done in the field, is likely to defer orsuppress the premature splitting and improve the overall connection performance. Therefore,these tests can be considered as representative of the "lower bound" performance of conventionalroof assemblies using MPC wood trusses.Figures 18 through 22 exemplify the failure modes observed in test specimens 5 and 6. Thehurricane clips changed the response and failure modes of the connections. Truss plate separationwas more frequently observed (Figures 18 and 22) and trusses rotated out-of-plane (Figure 19).The degradation of hurricane clips was caused by excessive deformation of the body of the clipdue to localized buckling of light-gage steel (Figure 20). One hurricane clip failed in tensionalong the cross section with two nail perforations (Figure 21).33
Page 2 and 3: PATH (Partnership for Advanced Tech
Page 9 and 10: LIST OF TABLESTable 1 - Selected Re
Page 11: LIST OF FIGURESPageFigure 1 - Rafte
Page 14 and 15: Section 3. Section 4 includes three
Page 16: Therefore, it can be assumed that t
Page 19 and 20: TABLE 1SELECTED RESISTANCE DATA FRO
Page 21 and 22: Uplift tests were conducted on toe-
Page 23 and 24: Table 3 summarizes specific gravity
Page 25 and 26: connections. Test results were used
Page 27: measurements were collected by the
Page 31 and 32: An examination of the load-deformat
Page 34 and 35: 32 percent. The differences between
Page 36: 4.1.4 Design ApplicationsThis secti
Page 39 and 40: 4.2 TASK 2 - FULL-SCALE ROOF-TO-WAL
Page 41 and 42: double top plate was fastened to th
Page 43: TABLE 16SUMMARY OF TEST RESULTS FOR
Page 47 and 48: Table 17 compares the experimental
Page 49 and 50: Maximum 0.2 sec design spectral res
Page 51 and 52: TABLE 18SPECIMEN CONFIGURATIONS FOR
Page 53 and 54: 700600500400Load, lb30020010010 cur
Page 55 and 56: Figure 26Toe-Nailed Joint ResponseT
Page 57 and 58: 5.0 SUMMARY AND CONCLUSIONSThe anal
Page 59 and 60: [7] Wilkinson, T. L. 1993. Bolted C
Page 61 and 62: APPENDIX ACALCULATION OF LATERAL NA
Page 63 and 64: Nail8d common -toe-nailedTABLE A3UL
Page 65 and 66: Nail8d common -toe-nailed16d pneuma

roof framing connections in conventional residential construction

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