Grain Systems Tanks PNEG-4105A - Manual (Page 105)

Chapter 7: Roof Assembly
Assembling a Double A-Frame
To achieve the required spacing between each A-frame, a double A-frame will need to be assembled prior
to installing and lift into place as one assembly.
Before You Begin
The double A-frame assembly will consist of three assembled roof rafters, purlin clips, and purlins. There
are also two different purlin clips, a left purlin clip (B) and a right purlin clip (C). The left purlin clip has six
holes, compared to the right, which has seven holes along the purlin clip mating surface.
NOTE: The seventh hole located in the center of the right purlin clip (C) is for identification purposes only.
No hardware is used in the location.
What You Should Know
DANGER
The completed assembly is extremely heavy, and all lifting should be performed by a
certified crane operator with prior bin construction experience. Never lift during
windy conditions.
When fully assembled the double A-frame becomes very heavy.
1. Place a roof rafter (A) parallel to an assembled A-frame (I).
2. Install left and right purlin clips (B and C) at locations shown, and secure the left and right purlin clips
to the roof rafter (A) using flange bolts (D) and nuts (E).Tighten to the recommended torque, see Bolt
Torque Specifications, page 25 specifications.
3. Install a purlin (H) at each location shown, and install flange bolts (F) and nuts (G).
IMPORTANT: The center rafter in the double A-frame will need to be assembled on blocks raising it
above the other rafters. This is necessary to adjust for the difference in rafter eleva-
tions due to the conical shape of the roof.
Figure 7-21 Double A-Frame rafter assembly with blocks
A Rafter D Block at the bottom (below the rafter)
B Block at the top (below the roof rafter clip) E Roof rafter clip
C Block at the middle (below the rafter)
Pneg-4105A 105 Ft Diameter 40-Series Bin 105