question about yy-column-buckling restraint 2

[PowerRanger]

Dear fellow
I have a question about the yy-column-buckling restraint. My case is following. a steel truss is supporting the timber joists. the xx-column-buckling restraint for the top chord is provided by the diagonals. so how about the yy-column-buckling-restraint. Can i say the joists provided it, or any other members provided the restraint?


Thanks for the time

 

[JAE]

You can count on the joists as providing restraint provided the joists are tied into some solid element at their other end OR they are connected to a diaphragm such as a plywood sheathing or a metal deck.

Also, if the top chord is fairly deep, and the joists sit on top of the chord, then there is a bit of eccentric bracing that exists and you should consider this in your connection to the chord member.

 

[UcfSE]

I agree with JAE.

You will have to provide an adequate connection to achieve this. If for instance the joists bear on the top chord without mechanical attachment then only friction would provide bracing connnection; not good. You should design a mechanical connection to handle the bracing force and provide details such that the bracing force can get into the diaphragm or joist and get to the ground. It all goes back to making assumptions, such as assuming the joists provide bracing, and then designing and detailing so that you justify your assumptions, such as designing and detailing proper connections.