Light Gauge to Masonry

[JMC3178]

I have 6" metal studs that are placed in front of a masonry wall to form the parapet. They are hanging from the wall and extend 5' past the top of the wall. I was planning on having angle braced studs from the masonry wall to the studs to carry the load. How do I connect an angled (45 deg.) 4" metal stud to the face of a masonry wall?

 

[JMC3178]

A picture is better than words.

 

[lkjh345]

JMHO:

Looking at your situation, The exterior face of the vertical studs appear to be about 12" off the face of the CMU. Any thought of just using 12" deep studs and just screwing (with Tapcons or something) the inside flange of the stud directly to the CMU>

As in most things, I think the less complicated construction would pay for the extra material.

My 2 cents.

 

[TimmyH76]

Can you come straight up off of the masonry and also put a brace horizontaly from the face of the masonry. This would eliminate the 45 deg connection?

 

[twinnell]

Instead of the angled braces, you could use straight studs normal to the face of the CMU and connect the stud to the CMU using a CL600 clip. This clip resists moment. Look it up on "The Steel Network" website.

You might be able to use this clip for angled braces as well.

Also, could run a track on top of the CMU and install a short knee wall up to the bottom of the parapet joists. Then install a diagonal brace from the top back corner of the parapet down to just above the roof deck @ CMU. Knee wall takes all vertical load and the diagonal brace takes the overturning force and puts it into the roof diaphram.

 

[ron9876]

You can extend a horizontal stud over the block wall and cantilever each way to pick up stud walls. Depending on load you may need a heavy gage angle to tie to top of wall and to horizontal stud.

 

[JMC3178]

Thank you for the speedy responses:

The occurance of this detail isn't too much, so I went with the 12" stud idea. I am questioning attaching it with Titan screws vs. DN52. I will be able to use continuous 6" (braced) studs when they will be able to be supported by the foundation below. Any other thoughts on the connection?

 

[onetimedeal]

How about the attached details? I think this may be a better detail.

1. First of all, I will transfer the concentrated load from roof deck to one of the panel points to avoid top chord failure.

2. A 12" stud has the web crippling problem (I did check). It may be better to design a 6" stud to take the lateral forces and use another 6" stud as infill to make up a 12" spacing.

3. Use clips to resist lateral loads and vertical loads.

4. Extend the 6" stud as a cantilever to resist lateral loads at parapet. It depends on how tall the parapet is, the 6" stud may need to use a stronger gage. The kicker is used to resist vertical and lateral loads from the right and the horizontal stud is designed only for lateral forces from the right. The idea is to transfer all forces directly to the structural masonry wall.

 

[lkjh345]

JMC3178:

Not sure you need the diagonal at the top or the horizontal just above the CMU. A 12" stud can easily cantilever up 6 feet and take the wind load as a cantilever.

 

[onetimedeal]

JMC3178:

You may want to consult a light gage installer for the 12" stud and make sure they can get this size. I think, at most of time, 12" stud is not readily available and they are pricing too.

In addition, you may want to check the web crippling for the 12" studs. Most of time, these 12" studs will fail by web crippling. You may be required to use web stiffeners.

Good luck.

 

[JMC3178]

onetimedeal, any suggestions on the clip? Just an 4x4 16Ga clip or is there a premfr. style?

 

[lkjh345]

Web crippling value for a 1200S162-68 (fy=33 ksi) will be around 1500 pounds using a 4" bearing width (I think in your case, you have more than 4", so you web crippling value will be higher). With your confiuration, you should not be anywhere near this value.

 

[UcfSE]

I would use 3.625" studs and place one vertical stud directly against the wall. The second stud can be placed at the wall face. Horizontals can then brace the outside stud back to the one against the wall. You will need only one diagonal to take care of the vertical load on the outside stud. Your connections would then be clip to the masonry with whatever fasteners you want. Tapcons or titens would be good. To get the cantilever to work you could place a short stud across the top of the wall and clip that to the top of the wall. That would put your fasteners in shear instead of tension.

Using a 12" stud in a 12" space would work, but it leaves no room for adjustment if the wall is out of plumb. This isn't the only option of course, but it gets them adjustment for tolerance and avoids 12" studs.