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Monorail Design

Monorail Design

Monorail Design

(OP)
Is monorail with two trolley possible?
I haven't seen monorail with two trolleys, any pics? Any publication and reference material about structural design of the monorail with two trolleys?
I appreciate if anybody had dealt with this in past helping me out

Respectfully,
Sk

RE: Monorail Design

Yes. I've done many of these. The two trolley rails I designed were manually powered, but I suppose they could be electrically powered as well. It is the same as a monorail with one trolley, you just have to design the runway rail and supports for two. If you know the trolley dimensions, you can figure out where the wheels will land on the bottom flange and cumulatively add the localized stresses in those areas.

You will have multiple load cases and locations you have to design for. It will take multiple attempts to find the maximum stresses in your member. I utilized RISA 3D and their moving loads to accomplish this. If you have a simply supported monorail, it will be pretty straightforward; link them together and send them running down the runway. If you have a multi span beam, it might take multiple iterations to figure where the maximum locations of hoists are located at, especially if the hoists are rated for different load capacities.

You need to get the CMAA specifications put out by Crane Manufacturer's Association of America. That is invaluable. Use this for one or two trolleys. You should perform the calcs by hand first to make sure you know what you are doing.

RE: Monorail Design

We had a discussion here recently where the spreader beam length was about as long as the chord of a quarter-circle of the track (i.e., the track radii were pretty tight), and there was some disagreement about side thrust and other dynamics.

Mike Halloran
Pembroke Pines, FL, USA

RE: Monorail Design

Two trolleys is common and likely required. A proper fall arrest plan requires a rescue plan and in a monorail/trolley system, you likely need a second trolley for the rescue.

RE: Monorail Design

(OP)
CCox (Structural): Thank you for your response and sharing your experience with me. Since, this is new subject to me first question is why they use two trolleys? Or in other words in what cases or for what purposes they use double trolley? Also, unfortunately I don't have any software to model all the cases and also don't know what are all cases with two trolleys. If you have a pic or anything of your past work that you can share that will be tremendous help to me.

Also, when a monorail is rated and labeled, is it based on one trolley or two trolleys?
The monorails I have seen just have the load rate on them and doesn't say that monorail is for two trolley operation or only one trolley operation?

Is linking the two trolleys and running them the worst case for a simply supported monorail?

CANPRO (Structural: Thank you for your response too. Do you know what are the two trolleys operation applications? Is there any minimum distance requirement when operating two trolleys? Any pictures of two trolley on a monorail? I googled and did not find any photos. Very hard for me to get any information.

Thank you gentlemen for your help.
StrP88

RE: Monorail Design

(OP)
Also, I forgot to ask, with two trolleys case, are there any requirement how the load is attached? If two trolleys picking one load, should be only with vertical slings or it can be angled slings to each trolley?

Is the two trolley case applicable for two separate loads each individually with one trolley?

Thanks

RE: Monorail Design

Yup... Dik

RE: Monorail Design

(OP)
Did I ask too much guys? Sorry? Just try to learn and understand. Didnt mean to take too much of your time. Just dont know where to find answers to my questions.

dik (Structural), sorry I didn't understand your response.

Thanks to all reviewer of the ad and the responders.

RE: Monorail Design

Typically these systems are used where access is limited. So if a worker using this system falls or is in some kind of distress (heart attack, allergic reaction, could be anything) using the monorail and trolley is likely the only practical way of reaching him. This is called a rescue plan and is something that is required in a proper fall protection plan. You need to design the rail for its typical use, a potential fall, and the rescue. You may need to consult with the owner and/or the end-user to fully understand how this system will be used.

Where is your project located? There is very likely some codes/standards you should be somewhat familiar with before you get too far into this.

A couple of videos for example...

https://www.youtube.com/watch?v=YchefXKLyfY
https://www.youtube.com/watch?v=TNI9qmE2MTE

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