T-56_Enclosure,_Appendix_B.doc

Figure 2. Detail of stiffener plate

Figure 3. Detail of stiffener plate Recommend installing two new plates to restore the load path.

Blue anchor plate is ¼” thick ASTM A36 steel, fillet weld per AWS D1.1 using E70xx filler.

Orange gusset plate is 3/8” ASTM A36 bolted in place to existing stiffeners and to anchor plate. Use the same fasteners in the new joint as are used in the stiffeners. Approximate width of the stiffener is the spacing of existing fasteners, plus 2 inches.

Figure 1. View from 940-S-001 p.12. Taken at bottom of stiffened closure plate, but detail is identical to area of interest. Stiffener depiction removed since it does not exist at cracked detail.

C-channel from circular section not shown

1. Excise crack from closure plate. Use rounded corners, and clean up cut edges.

2. Fabricate and install filler plate to match cutout from ¼” ASTM A36 steel.

3. Groove weld filler plate in place per AWS D1.1 using E70xx filler. Use caution not to weld filler plate to C-channel. Grind smooth as required to facilitate flush installation of doubler plate. Restore welds to stiffeners as required. Restore corrosion-resistant finishes in areas that will be covered by doubler plate.

4. Fabricate and install doubler plate from ¼” ASTM A36 steel. Fillet weld IAW D1.1 using E70XX filler.

5. Match drill holes at C-channel attachment locations.

6. Restore corrosion-resistant finishes (primer and top coat, as appropriate).

Slots in doubler plate to provide additional connection between plates.