Steel Bracing Connections

[Leftwow]

Ladies and Gents,

I'd like to discuss Bracing in Steel and how you what mods in structural softwares you guys in general are using for them.

In X BRACING, if they are connected in the middle are you guys setting Ly to 0.5*total length? I see engineers specifying to connect X bracing with one bolt in the middle a lot when I'm in the field. What about when we have spacers in a double angle or double C section? Can I reduce my Ly to compensate to the distance between the spacers? Also, I'm assuming the Ly is the only change. The Lz will stay the same correct?

In all bracing, I've read some engineers setting their K value to 0.8, to increase the buckling strength since overstrength factors aren't carried out in modeling software. Are you guys doing this? If you are, why?

I would appreciate any feedback you guys could give me, it would help me become a more efficient and better engineer.

 

[ash060]

Regarding X-bracing with the middle connection (like angles or tees), sometimes I will change the unbraced length to half of the distance if I can justify that the tension member has sufficient stiffness to brace the compression member. I use the equations in Appendix 6 of the specification for checking, I don't adjust anything because of the tension, I just check it as a flexural member (the tension will increase the stiffness).

If I am checking something that is existing I may look at it a little closer, if a more thorough analysis would prevent any modifications