Sixth week

From Peng

To file

11/17/2011

Test 8

8*-4x9-OSB-54mil-2’over-8’up seam-cyclic

Pre-test

No over-drilling screw found for test 8. Just 2 fasteners at the bottom is too close the vertical seam, the previous ones was missed the flange of bottom track. re-drilling, too close.

Strap is good,no gap.

Vertical Seam is in the middle, looks fine.

The additional stud is 1’ over. Fastener spacing  is 12in.

After-test

43 circle reference displacement:1.988in.

 The peak is 3929lbs,displacement is3.329in.

The failure occurs at the horizontal seam and vertical seam connection area first, then the fasteners on the vertical seam on the south board pull through OSB.

The 2 fasteners on the 2’x8’ OSB without additional field stud side pull out first at the 38^th circle. Fasteners on that OSB in vertical seam fail at 41^st circle. Fasteners near the horizontal seam pulled through, others near the bottom wood bearing failure observed. The fasteners tilted observed at the bottom of middle field stud.(2’ to the bottom)

2 fasteners at bottom on the OSB without additional stud failed, one near the vertical seam pull through, the other is wood bearing failure.

Tear-out failure observed at the edge of the horizontal seam.

The additional field stud is fine, no fasteners fail observed.

Fasteners at bottom go through 2 layers steel(track and stud) often get cut off.

 A little lifting up of the shear wall during the test. I don’t know if it is the reason of the hold down or the anchor not tight enough. Will see next test.

Photos

Pretest

Aftertest

 We observed the piece of steel under the washer on the holddown bent a little bit during the test.