Lateral Resistance 7–5.pdfVIP

7–1 Chapter 7 Fastenings Lawrence A. Soltis Contents Nails 7–2 Withdrawal Resistance 7–2 Lateral Resistance 7–5 Spikes 7–8 Staples 7–8 Drift Bolts 7–9 Wood Screws 7–9 Withdrawal Resistance 7–9 Lateral Resistance 7–10 Lag Screws 7–11 Withdrawal Resistance 7–11 Lateral Resistance 7–12 Bolts 7–14 Bearing Stress of Wood Under Bolts 7–14 Loads at an Angle to the Grain 7–14 Steel Side Plates 7–15 Bolt Quality 7–15 Effect of Member Thickness 7–15 Two-Member, Multiple-Member Joints 7–15 Spacing, Edge, and End Distance 7–16 Effect of Bolt Holes 7–16 Pre-1991 Allowable Loads 7–17 Post-1991 Yield Model 7–18 Connector Joints 7–18 Parallel-to-Grain Loading 7–18 Perpendicular-to-Grain Loading 7–18 Design Loads 7–20 Modifications 7–21 Net Section 7–23 End Distance and Spacing 7–23 Placement of Multiple Connectors 7–23 Cross Bolts 7–24 Multiple-Fastener Joints 7–24 Metal Plate Connectors 7–25 Fastener Head Embedment 7–26 References 7–27 he strength and stability of any structure depend heavily on the fastenings that hold its parts together. One prime advantage of wood as a structural material is the ease with which wood structural parts can be joined together with a wide variety of fasten- ings—nails, spikes, screws, bolts, lag screws, drift pins, staples, and metal connectors of various types. For utmost rigidity, strength, and service, each type of fastening requires joint designs adapted to the strength properties of wood along and across the grain and to dimensional changes that may occur with changes in moisture content. Maximum lateral resistance and safe design load values for small-diameter (nails, spikes, and wood screws) and large- diameter dowel-type fasteners (bolts, lag screws, and drift pins) were based on an empirical method prior to 1991. Research conducted during the 1980s resulted in lateral resistance values that are currently based on a yield model theory. This theoretical method was adapted for the 1991 edition of the Nationa