attaching to existing steel joists

[Stinch]

Would any one have typical information on how to attach to existing steel joists? I'm hanging a speaker from the joists and was going to attach to the top chord and was hoping to get information for light loads (under 250#). Is it common to drill the top chord for a new bolt (3/8" diameter)? Or is this not recommended?

 

[SwinnyGG]

250 lb is a relatively light load, but I would be reluctant to drill through a pre-fabricated joist. You most likely would not cause a stress-related failure, but you will expose bare metal and allow corrosion to begin.

The appropriate way to hang a light load from a steel joist is to use threaded rod through the center, between the two L-flanges, so that the load is centered along the chord.

 

[Guastavino]

Stinch,

Are you an engineer yourself?

And are these K-series joists or some other type?

 

[MotorCity]

You could also clamp Unistrut to the top or bottom chord near a panel point and hang the speaker from that. I would not cut or drill an existing joist.

 

[EngineeringEric]

unistrut between two truss bottom chords. hang load in center. each truss sees 250/2 = 125# which is below the 200# SJI requires reinforcement or at a panel... assuming your truss has excess capacity that is

 

[BadgerPE]

This is probably overkill for your issue, but I thought I would pass this info along that I got at a convention.

Chicago Clamp Company