Building Design and Construction Handbook - Merritt - Ventech!

10.60 SECTION TEN
FIGURE 10.12 Bolt spacing and edge and end distances are defined with respect to load
direction: (a) load parallel to the grain; (b) perpendicular to the grain. Reprinted with permission
from the American Forest and Paper Association.
TABLE 10.34 Minimum End Distances for Bolts*
Direction of loading
For reduced
design value
For full
design value
Perpendicular to grain 2D 4D
Compression parallel to grain (bolt
bearing away from member end)
Tension parallel to grain (bolt bearing
toward member end):
2D 4D
For softwoods 3.5D 7D
For hardwoods 2.5D 5D
* D � bolt diameter
10.16 LAG SCREWS
TABLE 10.35 Minimum Edge Distance for Bolts
Direction of loading* Minimum edge distance
Parallel to grain:
When L/D � 6 1.5D
When L/D � 6 1.5D or half the spacing between
rows, whichever is greater
Perpendicular to grain:
To loaded edge 4D
To unloaded edge 1.5D
* L � length of bolt in main member and D � bolt diameter.
Also known as lag bolts, lag screws are large screws with a square or hexagonal
bolt head. As is the case with bolts and timber connectors, lag screws are used
where relatively heavy loads have to be transmitted in a connection. They are used
in lieu of bolts where the components of a joint are so thick that an excessively