Momment on C-Channel Beam Clamp

[Gymmeh]

I am working on clamping hanger rod to a C- Channel C12@25lb/ft with a 3in flange.

The loading is:
Fs(load w/ design factor)= 4000lbs
M (Potential impact Moment at connection)= 4.16 ft-lbs

The C12 also has a little taper which I don’t know how much I need to consider. I am planning on having bracing run to the connection of the threaded rod and clamp so there is no chance is could loosen up.
The closest clamp is:

http://www.mcmaster.com/

part 3235t83

This clamp design is for 4050lbs working load but I don’t know how well the clamps respond to moments.
Is the moment a major concern with these clamps? Is the extra bracing over kill?

 

[hokie66]

I see three problems, or at least potential problems:

1) What is the M? How do you get only 4 ft-lbs when the load is 4000 lbs?

2) This type clamp on a tapered flange will tend to slide down, loosen, fall off. I suppose the bracing is intended to resist this movement, but how would you connect that to the clamp? Even if you can, see comment 3.

3) The load is applied far from the shear centre, thus causing the channel to twist.

 

[Gymmeh]

This is a device to lift 250lbs parts.

1) All force should only apply a downward. However ANSI requires the design to resist 50% of the rated capacity for horizontal impact. The moment should really be 599 ft-lbs. (sorry conversion mistake).

The total weight of lifting equipment with load will be 917lbs, with a design factor of 4, we get just under 4000lbs (Used for analyzing the clamp and hanger rod).

2) I told the Union workers (part of the problem) … that I wanted them to drill two holes and bolt to another piece of steel with two 5/8 Grade 5 bolts and attach a mounting flange. Of course they gave me the old “I have used beam clamps for 50 years”…so I figured I would try to make this work, although there are so many issues with it…as you noted, this will effect the C-Channel. I am only supposed to design up to the clamp; I told the head maintenance man all the problems with what they want to do vs. the easy way of doing it. Then the workers started comparing me to a lawyer...

2) Adding Bracing:
The clamp has a taped hole for threaded rod, just below the hole I plan on having a plate with the threaded rod runs through. I will get a CAD drawing.

 

[Gymmeh]

hokie, Thanks for your imput

My boss just asked me for an update on this project, then told me to scrap it if they me to do a "barn job".

Cheers

 

[dvd]

Please don't blame unions for people's individual quirks. I happen to be an engineer who is pro-union.

See if the type CF clamp could provide you with a secure connection.

http://www.lindapterna.com/index.php?searchcriteria=channel&pid=search&x=16&y=8

 

[Gymmeh]

dvd,

thanks they can do it!

Just not in the with in the deadline...

 

[dvd]

Good luck with the channel clamps.

Better luck with your career working with people you don't seem to like.