Sag Rod Support 1

[bdSE]

I am designing an industrial building to house a process plant, the frame is clad with C10 wind girts which span 20' at each bay. I have decided to use sag rods in my design.

Based on my investigations here I have found several excellent discussions regarding the use of Sag Rods for providing bracing to wind girts.

What seems to be missing from my research is information regarding the end support of the sag rods. Are they supported at the eve by a dedicated beam for the gravity and bracing loads? Are they also connected at the foundation? Or do they simply connect to adjacent steel members?

I am assuming it is supported at the eve level and I have some creative ideas for providing this support, but did not want to wander too far from typical practice.

Thank you for your time,
- bd

 

[ToadJones]

There are many different arrangements for different building types that can lead to many ways to support the sag rods.

In some of the industrial structures I have worked on there are struts along the column line at or near the eave height. The girt line is typically 2'-0" or so. So what I would wind up with is an eave beam and a column line strut running parallel between which small sag-rod-support-beams would be run (2' long or so). Looking up at it, it looks like a ladder. This ladder also supports the gutter trough one way or the other. The eave beam would have to be supported by an outrigger in this case.

Keep in mind this situation is on heavy industrial buildings, not PEMB or the like.

 

[ToadJones]

in lighter applications the last roof purlin can double as the eave beam resting on outriggers (out to the girt line). The sag rods can be hung from the purlin so long as it is sized to carry the wall girt load.

 

[DaveAtkins]

And if you have open web steel roof joists that are perpendicular to the wall, the joist seats can cantilever over the edge beam to provide support for sag rods.

DaveAtkins

 

[BAretired]

What about carrying the sheeting on the foundation?

BA

 

[JAE]

Many of our buildings are using thicker insulated metal panels, like these: (Panel webpage)

They typically rest on concrete grade beams and support their own weight.

For lighter panels, they still have vertical flutes, typically, so they have some ability to support their own weight provided the girt spacing isn't too far. Otherwise providing a rigid continuous edge angle that can support the vertical load - usually cantilevered off the edge beam - is used.

I'm sure there are many other approaches.

 

[ToadJones]

I usually, conservatively, assume the wall load is carried at the eave beam/strut. Siding loads girts, girts load sag rods, sag rods load eave strut or other supporting member.

 

[ToadJones]

Some of the PEMB I have erected in the past had no sag rods at all. I had to cut wood blocking with keep the Z girts level and straight until we fastened the siding.