SCBF Single Story Configuration
SCBF Single Story Configuration
(OP)
Does anyone have an opinion on the most efficient SCBF single story configuration?
I was thinking of either a V sshaped brace (not an inverted V) or an inverted brace with a zipper column.
Thoughts?
I was thinking of either a V sshaped brace (not an inverted V) or an inverted brace with a zipper column.
Thoughts?






RE: SCBF Single Story Configuration
If you do use X-Bracing, pay special attention to the connection at the intersection. It's best to use a connection that doesn't rely entirely on catenary action if you can (i.e. avoid a single knife plate through the brace - square HSS members make use of dual cover plates easier).
RE: SCBF Single Story Configuration
RE: SCBF Single Story Configuration
RE: SCBF Single Story Configuration
From the little I know, in an SCBF single story inverted chevron, the beam must take the full yield strength of the tension brace, considering the compression brace has buckled, which is no small feat. The X brace and zipper column configuration allows you to avoid this penalty.
If Im wrong, anyone, please let me know.
RE: SCBF Single Story Configuration
As a rule of thumb:
For H/W = 0.5-1.5 tension only braced frames
For H/W = 0.3-0.4 chevron braced frames
In terms of fabrication efficiency as sandman21 alludes to I'm not sure if chevron bracing does win over X bracing. With chevron bracing you may need to detail stiffeners and add bottom flange bracing on the supporting beam.
RE: SCBF Single Story Configuration
RE: SCBF Single Story Configuration
For inverted V-Bracing you will need to design the beam for the capacity of the braces (horizontal and vertical component). You usually end up with a huge beam.
V-Bracing would require the anchorage to be detailed for this load in a 1-story configuration. That will be tough to do.
RE: SCBF Single Story Configuration
An X-brace will require ten reinforcement plates v. eight reinforcement plates. Five gusset plates with plate stiffeners that need to be installed properly v. three gusset plates. Keep in mind that the hinge zone tolerances are extremely tight, it's not uncommon for errors that require extensive fixes. It is easy to provide a zipper column to take the unbalanced load.
RE: SCBF Single Story Configuration
The building is a small, L-shaped, two story school (cat III) with a one story portion. The one story portion is the small leg of the L, which projects only 70 feet from the main building
My thoughts were that the beam would be excessivley large to accomodate the brace force.
Thoughts?
RE: SCBF Single Story Configuration
I designed a performing arts center with a single story portion that has frames that are 26' wide by 18'-6" T.O.S, the braces are HSS 6x6x3/8, zipper columns are HSS 8x8x1/2" and the beam is a W18x50. The only part that can get out of control is the zipper column there are things you can do, consider fix-pin, which we did not. We have moved away from SCBF and will be using BRBF when we need to use SCBF. From our research the BRBF will have cost savings over the SCBF.