Crane Rail & Hook Bolts

[nilaypathak]

Hello,

Thank you in advance for you valuable time.

Pre-Engineered Building Design Engineer do not agree to use crane attachment detail proposed by crane vendor supplier, C- channel on top of crane runway I-Beam. Building design Engineer argument : we have installed many crane rails on I-Beam, top flange wider, without Chanel.

My questions:
1) What makes different with C-channel on top of I- beam and only I-beam as crane runway beam to set rail?
2) What should be division of responsible of Building Design Engineer and Crane supplier?



Thanks,

 

[jdgengineer]

The purpose of the channel on top of the I-beam is to take the lateral loads for a top running crane. Typically, in this situation the channel alone is designed for the lateral forces rather than designing the I-beam in torsion. If instead the I-beam alone is called for these forces (and torsion as required) then the channel is not necessary. Typically, this works for relatively light cranes with modest spans.

In the past I have seen different divisions of responsibility. Sometimes the metal building manufacturer supplies the runway and sometimes the crane sub does.

 

[amec2004]

The C channel capped on top of wide flange will provide larger minor axis Iy and Sy value for the combined section. You can check the AISC Design Guide 7: Industrial Buildings-Roofs to Anchor Rods 2nd Ed section 18.1 on page 56, it assumes the capped channel plus W section top flange resist the lateral load. The use of capped channel will increase minor axis Iy and Sy value, radius of gyration rt, and thus increase the crane beam’s flexure resistance and also bring down the lateral deflection value.

You definitely can use the W section without capped channel if it can pass the design. For a quick check you can go to

http://www.civilbay.com

and download the crane beam design or crane girder design spreadsheet and run a quick check. The crane beam design spreadsheet can handle crane runway beam design with and without cap channel.

 

[jdgengineer]

By the way I miswrote. With a top running crane the I beam is not usually calced for torsion. So typically I believe to simplify the analysis only the top flange is considered effective in resisting the lateral forces. If just the top flange alone doesn't work then you'll put a cap channel on top and calc just the cap channel for the lateral load. Then you have a choice to upsize the beam to a size that works without the channel or put on the channel. Depending on the increase in steel weight required the channel may or may not be economical.

 

[ToadJones]

What is all the talk about a cap channel and its design intent????
This is not what the OP is asking.

The crane supplier should not care at all what the runway girders are or if they have a cap channel or not.
The crane MIGHT have some concern with rail size, but it ends there.
If the building designer designs a girder where no cap is needed, thats it, it doesnt require it.

IMO, depending on crane size/capacity, j-bolts are not the way to go. J-bolts for certain runway girders and girders with caps have to be custom made and are only good for light duty cranes. You and the client are much better off using rail clips.

 

[amec2004]

Original post is asking
1) What makes different with C-channel on top of I- beam and only I-beam as crane runway beam to set rail?

The originator wants to know what makes the difference for crane runway beam to use cap channel or not to use cap channel. You can go to

http://www.civilbay.com

and download the crane beam design or crane girder design spreadsheet and run a quick check on the crane runway beam design. The AISC approach of designing crane beam assume the W section’s top flange, or W section’s top flange combined with cap channel take the lateral load and thus no torsional analysis is required.

With regard to the crane supplier and crane runway beam supply, it all depends on the contract. I have seen crane supplier submit vendor drawing with crane runway beam design, connection design numerous times in the past.

 

[nilaypathak]

Thank you for your input.

Any ref. materials for selection of attachment detail of rail to runwaybeam.

 

[spats]

See the 13th Edition AISC Steel Construction Manual, page 15-4.