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Wood, Dowel Bearing Strength for Founation Redwood -Reply

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Sam,

Since the redwood grain pattern can be either, it is always conservative to use
the less dense values. I once asked someone from the redwood association a
similar question about existing buildings. He stated that most older buildings
have the denser old growth  and the new modern buildings have the less dense
open grain. Is your building new or existing? Even if you have an older
building, it may be difficult to verify the grain pattern of in-situ lumber.

Also, the anchor bolt reduction will not be as great as the reduction for the
structural wood panel shear values. The use of open grain redwood is a 35%
reduction and close grain is 18%. See Footnote 1 in UBC Table 23-1-k-1. This is
a common design error when using existing construction.

Regards,

Tim McCormick, P.E.
City of Los Angles

>>> Szuchuan Chang <szchang(--nospam--at)pacbell.net> 04/03/98 12:40am >>>
I am in the process of using NDS table 8A to get the Dowel Bearing
Strength
for Bolted Connection. (Anchor bolts for shear wall.)

Table on NDS page 36 has 2 entries for Redwood (close grain SG=0.44 and
open
grain SG=0.37).  Which one should I use for Foundation Redwood?

Thanks in advance.

Sam Chang, SE
Cupertino CA