Interpreting Analysis Results Near Joints

[David Deck Guy]

I have an issue where I am trying to connect a pergola, topped with solar panels, to a less than ideal masonry wall. The pergola posts are pinned at the top, so my connections to the wall need to be fixed for lateral stability. This moment connection wont pencil out.

Another option is to run a tube in the roof, weld the post to the tube for a moment connection, and design the tube-masonry connection as a pin. This design would function like an upside moment frame. While it pencils out, I don't know if its realistic to consider that the moment will go into the beam-tube when the masonry pin connection is only 4" away. I'm worried the masonry pin connection will fail as a moment connection before the beam-tube sees any load.

Am I at a point where I can tell the contractor and architect that we are good to go, or do we need to go back to the drawing board?

 

[David Deck Guy]

It might be a moot point since we may be returning to a previously vetoed design, but after thinking some more about this I am just too uncomfortable with it as drawn. However, I think I could get this detail to work by moving the "pin" to somewhere in that 4" gap, and making it something that I can be confident will be a lot more ductile.

 

[WesternJeb]

Structures act how you detail them, not how you design them. If you weld the HSS tube all around, it will transfer moment without a doubt.

You will need to detail a special connection that includes some form of bolted connection. I typically weld a cap plate onto the HSS tube, have a shear tab coming off of both the face mount plate on the CMU and the face mount plate on the HSS, and then bolt the shear tabs together. This will give you more of an idealized "pinned" as you are designing for.

In addition to this, how are you planning to connect to masonry, adhesive or mechanical anchors? I rarely get any face mount connection to CMU to work with any significant load on them.

 

[David Deck Guy]

That is exactly what I plan to do. It will make the whole thing more constructable as well.

As for the anchors, I'm going with Hilti HAS 3/8 dia. anchors with HIT-HY 270 adhesive.

 

[WesternJeb]

Sounds like a great plan to me, I just noticed your sketch had a welded symbol so I wanted to make sure!