Monorail Design 1

[vincentpa]

I am collaborating on a spreadsheet for the design of monorails for underhung hoists. My colleague is a bit older than I am and has some formulas and information that we cannot verify. He has been working in the industrial sector and this is the way it was always done. I would like to verify these formulas and information so our spreadsheet can be complete and I understand the logic. The problem we are having is with local flange bending, especially for S shapes. AISC does not address local flange bending caused by a point load applied to the flange. AISC only addresses local flange bending for moment connections with a plate welded to the flange. These are my questions:

1. What is the effective length (cantilever length) of a flange in local bending?
We use:
W-shape: bf/2 - k1
S-shape: (bf-tw)/2 - R
R for an S-shape is the radius of the fillet. We can't find the R anywhere except where he had it written down, so we can't verify the values.

2. How do you calculate the effective flange thickness of an S-shape?
We use: tf + (effective flange cantilever - calculated above) x 0.166.
We can't find any references for this equation. It was just always done that way. Does anyone know this equation? What do you use to calcualte the effective flange thickness of an S-shape?

3. How do you determine the effective width of a flange in local bending? We use: 2 x (effective flange cantilever length)

4. Perhaps you use the same equations and information. If so, do you have the references. If you use other methods, do you have referenced for those methods.

 

[DaveAtkins]

I will try to help with questions 2 and 3.

I seem to remember that the slope of an S-shape flange is 1 in 12. If you know the thickness of the flange tip, this will give you the thickness at the radius.

I use 2.5 times the cantilever length for effective width in this type of situation. This is from Fisher's book on joist and joist girder design.

DaveAtkins

 

[kslee1000]

Visit

http://www.aist.com,

and get a copy of Publication No. 13.

 

[vincentpa]

what is aist.com? I cannot connect.

 

[kslee1000]

Sorry.

http://www.sist.org

 

[IJR]

kslee

did you mean aisc.org? The sist is about tonsils.

 

[vincentpa]

Website still doesn't work.

 

[vincentpa]

what is the title of this publication? I've tried AISC and I get nothing on a search. do you have an author and date? Publication name?

 

[kslee1000]

Need more coffee!

try again.

http://www.aist.org

(The Association for Iron & Steel Technology)

 

[kslee1000]

Ok, the link below take you directly to the book order page. It is the first one, TR-06. But before you spend the money, let me check my copy to make sure it covers your need.

http://steellibrary.com/CatalogResults/tabid/55/Default.aspx?searchBy=Title&criteria=067082065078069

 

[kslee1000]

Below is link to AISC pub/tools related to crane runways. A good to do some research.

http://www.aisc.org/search.aspx?id=3852&keyword=crane beam

 

[CTW]

TR-06 is the Specification for electric overhead traveling cranes for steel mill service. I don't think this is going to help you out very much nor is TR-13.

Publication number 74 from the Crane Manufacturers Association of America (CMAA) will help you out. It outlines how to calculate local bending of flanges due to wheel loads. It's not expensive and worth it to have as a reference.

 

[BAretired]

I'm not sure that I can add anything very useful here, but according to the CISC Handbook of Steel Construction, the inside flange of S shapes have a slope of 16 2/3% (2 in 12).

1. Formulas seem reasonable. R for S shapes is not given in CISC Handbook either.

2. I don't know what you mean by "effective flange thickness" of an S-shape. It is not a property I have ever calculated.

You said:

We use: tf + (effective flange cantilever - calculated above) x 0.166.

If tf is the thickness at the flange tip, your formula would give you the thickness at the start of the fillet. However, CISC lists mean flange thickness. If tf is mean flange thickness, the formula makes no sense to me.

3.

How do you determine the effective width of a flange in local bending? We use: 2 x (effective flange cantilever length)

I don't know what is meant by effective width in local bending, so I cannot help you.





BA