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Coefficients for Cantilevered Monorail Crane 2

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dik

dik

Structural
Apr 13, 2001
25,679
In the attached spreadsheet, does anyone know where the coefficients come from. There are different values for S Sections and W Sections, and I want to use a T Section comprised of a C Section and an S Section.

Coefficients (Cx and Cz):

Clipboard01_hrr8ys.jpg


and the spreadsheet:



Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik
 
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Dik,

I am unable to open and view your spreadsheet as attached to the Eng-Tips bulletin board.


Jim


 
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It comes from CMAA #74 3.3.2.6. Local bending of flanges due to wheel loads (hanging). These coefficients are applicable to an S beam. Capped S beam would not affect the calculation since this equation applies to loads on the bottom flange.
 
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Thanks... I'll take a gander; I have the doc... The spreadsheet has different values for S and W shapes, I guess to reflect the tapered flange.

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik
 
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I didn't check when I uploaded it, but I have no trouble in downloading the file. You might try again.

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik
 
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Yep, Cx and Cz change depending on if it S or W. These local stresses are critical for the simply supported condition and not usually for cantilevers though, since peak flexural stress for the cantilever happens at the support.
 
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Thanks... two different issues but checking the flange for bending at the 3 location as part of the SMath program. It's a 6K monorail with a 9' cantilever and a 10' backspan. LTB was my first concern, but check local triaxiality, too. On a positive side, the load is below the shear centre.

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik
 
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I would be surprised if deflection in the cantilever doesn't control design.
 
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Yup... L/370 as opposed to L/600. OK with the caveat that it is non-conforming and that special consideration be made to secure the load in case it wants to move 'downhill'.

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik
 
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Non-conforming deflection can sometimes be accounted for by upsizing the drives to deal with uphill motion.
 
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I think the hoist is motor driven, but I don't think the rest of it is... hence the caution. I'm concerned that it could be free wheeling downhill... and if it starts to move, the deflection will increase want to move downhill even faster.

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik
 
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Dik,

I am still unable to download and open this file. It seems that others are not having the same problem. I get an interminable download of what is probably a relatively small file. So I don't know what the problem is, but I guess I am going to let it go and not worry about it. I have EXCEL 365 on my home computer and normally am able to open most everything/

Jim

 
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Dik:
You could tie the canti. tip back to the high canti. support point with a sloped round bar and turnbuckle. You could adjust this so the deflection was approx. zero when the load was out at the tip. In effect, you would set the tip .5” high when there was no load on the canti.
 
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The spread sheet has a bunch of hidden columns
you will note the spread jumps from column J to BA
all column in-between are hidden and full of the math the developed the coefficients
we have reworked this sheet A lot... to the point where it now has cap channels on the beams
 
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How were you able to access it? I tried to get past the protections. I did an SMath sheet to do a capped beam, but from the formula published in the original sheet.

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik
 
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I never bought that a hoist would struggle with a slope greater than L/600. You can probably can't even guarantee the monorail is installed that flat. Either way, the slope on a cantilever at L/300 would be about equivalent to the slope on simply supported beam at L/600.
 
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dik said:
How were you able to access it? I tried to get past the protections.
Click to expand...

Right click on the sheet tab on the bottom and select unprotect sheet. It isn't password protected.
 
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Thanks...

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik
 
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I would think more severe... due to the short backspan and that for the L value, I used the cantilever span. My concern is that as it deflects, there is a chance for the load to 'run away' with the increased deflection... but, I guess that's why I added the 'enhanced' end stop.

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik
 
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Does anyone have a formula to calculate Cbo rather than use a 'lookup' table? I found some curve fitting programs I wrote from 20 years back... done in BASIC and a copy posted to the 'Engineering Program Apps' forum. They were from a HP publication from way back, too.

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik
 
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