A Shear Wall Between Openings

A Residence Wall Resisting Seismic Loading
Wall Information:

Vroof = 800 pounds.  The weight of wall is 7 psf.  A roof contributes 350 plf to the top
of this wall. The seismic coefficient is 0.183 and we are located in Zone 4.  Height = 8 feet.
Width = 4 feet. The wall is framed from 2 x 4 Douglas Fir No. 1 except as required.
The footing is 16" wide and 18" deep concrete. For simplicity, assume each header
is 4 foot long.

A Wall Between Headers To Resist Seismic Loading

Let's start with the easy stuff...

Checking for compression posts and hold-downs...

Compression posts

Because we can already see that the hold-down force is going to be low, we can start by assuming a minimum hold-down capacity of 1000 pounds (the minimum for listed hold-down anchors) and do a much simpler calculation...

End Stud Check
The distance "a" (see previous diagrams) indicates the distance to the centroid of compression forces.  (3 * a) is 2.67 feet.  The load on the end stud is (1245)*(1/2)*(16/12) + (2/3)*(1245)*(16/12)*(1/2) = 1383 pounds...plus the load from its header...for 2083 pounds total.  The adjacent stud would resist at most (3324 - 1383) = 1941 pounds.  Both are within the calculated limits, ok.

Shear and Sheathing
Our unit shear in this wall is 210.25 lbs./ft.  2x members are sufficient for framing all around.

The thickness of sheathing was not specified in the beginning, so we are left to select that as well as the nailing. Looking at Table 23-II-I-1 on page 2-288 of the 1997 UBC, we see our choices are:

Sill Bolting
Looking at Table 23-III-B-1 on page 2-296, we see that the value for 1/2" diameter bolts in 2x material parallel to grain is 480 pounds.  With a 1.33 increase, this makes 638 pounds..

4 feet * 210.25 = 841 lbs.

(841) / (638) = 1.32 bolts > Use two 1/2" diameter bolts.  Space them at 16" centers near the interior of the wall to leave room for the hold-down bolts at the ends.