Examples
1. trusses (if loads applied directly to pinned joints at centroids)
Photos taken by Jeff Thomas
in Fort Dodge, Iowa
on April 27, 1999
Photos taken by Jeff Thomas
in Memphis, Tennessee
on June 15, 2000
Photos taken by Tomas Zajicek
in Steam Boat, Colorado
in the summer of 2002
Photos from trussnet.com and
by Jeff Thomas in Rolla,
Missouri on January 23, 1999
Photos of Stuart Bauer
taken by Jeff Thomas at the
University of Missouri-Rolla
on November 11, 19992. chords of shearwalls and diaphragms (⊥ to applied load)
3. collector or drag struts (// to applied load)
Stress Parallel-to-Grain
ft = P/An ≤ F't
Tu ≤ F'tnAnsolve for required net area (no trial-and-error)
Fasteners (chapters 11-13)
Anet = Agross - ΣAholes
ΣAh = sum of projected area of holes at critical section
1. nail holes
usually ignored
2. bolt holes
(bolt diameter + 1/32" to 1/16") x width of member (NDS section 11.1.2.2)
C11.1.2.1 Forcible driving of the fastener can damage the wood-bearing surface and reduce the capacity of the connection.
3. lag bolts
shank diameter, diameter of pilot hole for threads (NDS appendix L)
4. split rings & shear plates (NDS appendix K)
dap or groove, bolt hole
Staggered Fastener Patterns (NDS section 3.1.2)
TB-206 Fastener Spacing in Weyerhaeuser Engineered Lumber
3.1.2.2 For parallel to grain loading with staggered bolts, drift bolts, drift pins, or lag screws, adjacent fasteners shall be considered as occurring at the same critical section if the parallel to grain spacing between fasteners in adjacent rows is less than four fastener diameters.
3.1.2.3 Where split ring or shear plate connectors are staggered, adjacent connectors shall be considered as occurring at the same critical section if the parallel to grain spacing between connectors in adjacent rows is less than or equal to one connector diameter.
Field Installations
post base with steel boot (source)
Adjusted Design Values
F't = Ft(CD)(CM)(Ct)(CL)(CF or CV)(Cfu)(Cc)(Ci)(Cr)
F'tn = FtKF(Φt)(λ)(CM)(Ct)(CL)(CF or CV)(Cfu)(Cc)(Ci)(Cr)