Questions about X bracing
Questions about X bracing
(OP)
Hello Structural Community!
Here is a background.
I have a scenario where I'm assuming existing bracing can't withstand compression and would work in a tension system only. I know that AISC is discouraging the use of tension only systems because of increased risk.
However I just have a few questions regarding bracing
1. What K-values are you guys using? I've read that you can use up to 0.7 as a maximum and most people are using 1.
2. If you have an WT section that is connected in the middle, can you set the Ly as half the brace length?
3. In the situation of 2, how can you set your Lz as half the brace length when you still have a k value of 2?
I understand if one brace goes into tension and the other in compression that the brace in tension is theoretically bracing the other brace in compression but wouldn't they have a tendancy to slide? Then put eccentric force on the tension member?
Here is a background.
I have a scenario where I'm assuming existing bracing can't withstand compression and would work in a tension system only. I know that AISC is discouraging the use of tension only systems because of increased risk.
However I just have a few questions regarding bracing
1. What K-values are you guys using? I've read that you can use up to 0.7 as a maximum and most people are using 1.
2. If you have an WT section that is connected in the middle, can you set the Ly as half the brace length?
3. In the situation of 2, how can you set your Lz as half the brace length when you still have a k value of 2?
I understand if one brace goes into tension and the other in compression that the brace in tension is theoretically bracing the other brace in compression but wouldn't they have a tendancy to slide? Then put eccentric force on the tension member?






RE: Questions about X bracing
Below is the front end summary and one of the concluding paragraphs:
If you are an AISC member it is free (or $10 if not a member)
Found HERE
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RE: Questions about X bracing
RE: Questions about X bracing
RE: Questions about X bracing
RE: Questions about X bracing
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RE: Questions about X bracing
With the AISC blurb, what do we make of the "discontinuous midpoint connections" bit? Can we safely assume that we're good to go with K=0.5 so long as one of the braces is flexurally continuous across the joint? Conversely, if the brace forces are about equal, are we really able to go with K=0.5 even when neither brace is flexurally continuous across the joint? Pretty great to have an official AISC statement on this now.
I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.
RE: Questions about X bracing
RE: Questions about X bracing
I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.
RE: Questions about X bracing
No. The base paper only had one or the other discontinuous, though I see how that could be confusing from the verbiage. 2022...