Bolting of Crane Rail

[jpsanfor]

I'm working on a project replacing a telescoping conveyor boom. The rail is attached to the underside of the boom truss. The original rail was riveted through the base of the rail into the double angle bottom chord. We are using a WT as the new chord but still want to bolt the base of the rail directly to the tee. Is there any reason this cannot be done? Using clips would be more expensive and would require a wider/heavier section to make the attachment. Of course the clip manufacturers want you to use their clips but I know you can order rail that is drilled. Also, is there any information or guidance on bolt spacing out there?

 

[thaidavid40]

My first inclination is to not recommend this detail as you describe it. A cross-section sketch would help.
Dave

Thaidavid

 

[jpsanfor]

Here is the rail attachment section. The flange would have to be wider and the tee section heavier to allow the attachment of the rail using clips.

 

[kingnero]

What forces will act on the rail?
That might be interesting to know, in order to comment on the fixation of the rail.

If I read your drawing correct, your rail is equivalent to 40kg/metre, which is about 2/3 of trainway size rails.
Does your application really needs such heavy rail?
Wouldn't flat bar (say, 1" square) suffice?

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[jpsanfor]

Maximum vertical reaction would be about 60 kips with a side loading maximum from wind of about 8 kips.

 

[MikeHalloran]

Unless the 60 kips acts in an upward direction, I'm not understanding how the detail works.


Mike Halloran
Pembroke Pines, FL, USA

 

[jpsanfor]

You are correct. The 60 kips (worst case) is a vertical reaction force due to the weight of the conveyor boom truss. The above detail is a section of the bottom chord showing the rail that rides on wheels mounted on the main support structure. My question is about how it is attached and I think I have the customer convinced to use rail clips but ultimately cost will decide. I wanted to gauge if direct bolting as shown is recommended.

 

[MikeHalloran]

I suspect the lowest installed cost will be associated with hook bolts. The rail supplier can punch the holes in the rail web, and supply the correct hook bolts and nuts, given a reference to the WT's flange dimensions.

... It won't be quite as easy as installing crane rail with hook bolts on top of a W runway, where gravity helps to stabilize the crane rail until you can adjust and tighten the nuts. Your contractor might need shoring or large clamps for that purpose, unless they can invert the entire truss for a few hours.





Mike Halloran
Pembroke Pines, FL, USA

 

[hokie66]

My gut feel is that you are best to stick with bolting the rail on as shown in your section.

 

[dik]

Unless I'm reading this wrong, 60K tension on a 3/4" A325 bolt seems a tad high unless you are using adjacent bolts to assist... fatigue would be an issue to consider...

Dik

 

[jpsanfor]

The load would vertical positive on the rail in the sketch above. No tension in the bolts.

 

[dik]

Thanks, I was just wondering what was holding the rail to the T section... assuming the loading was to the underside of the rail head...

Dik

 

[MikeHalloran]

How does the I of the WT compare to that of the double angle you're replacing?
I'm thinking you might need to add a flange to the web of the WT to prevent buckling.

Mike Halloran
Pembroke Pines, FL, USA

 

[jpsanfor]

The double angle with a plate in between was about 38 plf so the tee being 47 plf is heavier and has a ltitle more section.