Cable support system

[jimtheengineer10]

See the attached picture for clarification. I have been asked to design a support system for a condensing unit. I have never done something like this before so I have some questions. The cable will be fastened to a 12" solid brick wall. What type of connection would need to be provided into the brick and what size/type of cable? The brick can be removed and a steel plate installed to support the steel beam under the condensing unit.

 

[JAE]

I would be wary of doing this if the brick wall is a brick veneer over some kind of back-up wall.

Brick veneer probably isn't capable of supporting the outward horizontal component of the load.

Typically for veneer conditions you want to cable back to the main structural wall behind the veneer.

If this is a multi-wythe brick wall, even then I'd be worried about pulling the outer wythe off the wall and so the anchor would have to be embedded deep enough to ensure that wouldn't happen. There are multiple kinds of brick/masonry anchors - try Hilti or Simpson for two suppliers.

 

[structSU10]

Agree with JAE, the horizontal component of that force will be a big problem for the brick.

You might be able to have the connection go through the wall and connect to a spreader beam to help distribute the load the the wall, or connect it to the main structure if it is a veneer wall.

 

[msquared48]

I always use either a thru-bolt to a spreader plate on the backside of the wall, or a direct connection using a simpson strap anchor to any substantial framing beyond. I just have a thing about trusting any masonry anchors psrtly embedded in old brick and mortar walls. But that's just me I guesss...

Mike McCann
MMC Engineering

http://mmcengineering.tripod.com

 

[tony1851]

He says its 12" solid brick wall (not veneer) but the sketch doesn't show how much brickwork is above the anchorage
point. If there is sufficient weight of brickwork above, my guess would be a metal plate on the inside of the wall.

 

[JAE]

I see where the term <12" solid brick> is used... I'm just used to some referring to a wall that has brick on it and is 12" thick as a "solid" brick wall.
Might not be "solid".

 

[msquared48]

Solid comment JAE!

Mike McCann
MMC Engineering

http://mmcengineering.tripod.com

 

[jimtheengineer10]

I have some more information on this.

See the attached drawing for reference.

The wall is a 12" thick brick wall (grouted). It extends about 20' above the roof. The contractor is proposing to fasten an L channel to the brick wall and use thru bolts to a steel plate on the inside of the wall. The L channel would extend out approximately 6' from the wall. If necessary a diagonal steel member would be welded to the top of the vertical angel and to the end of the horizontal channel.

Does this approach make sense? If so how do I go about determining the size of the L channel? I have sized W beams before but never L channel.

Thanks.

 

[MikeHalloran]

Uh, "L channel"??

You need to rent an actual engineer.
This stuff is outside your expertise, and you are risking property damage and/or personal injury. Get help. No, that's not what we do here.





Mike Halloran
Pembroke Pines, FL, USA

 

[jimtheengineer10]

Sorry I meant Steel Angle and not L channel. The shape of the steel angle is an L shape. Sorry about that

 

[JAE]

I think with your new sketch there would be the concern over bending of the brick wall at the base.
The bracket assembly you drew is extremely eccentric to the wall. The wall would have to be checked against
tension failure on the back side as it rolls over, resisting the load on the other side. This would be a check on either maximum tension in the brick (which is small) based on any initial axial compression in that back side due to self-weight of the wall.

Do you know how to do this type of check?

 

[jimtheengineer10]

After reading the responses here and looking more into the project I advised my client that I could not provide the design he needs as my experience with this type of support system is limited. Thanks for all the help.