QUESTION REGARDING 18B40 (LIGHT BEAM SECTION PROPERTIES)

[katy...@cox.net]

I have an existing structure built in 1970 and the structural drawing calls out a 18B40 beam section. My AISC Steel Manual 6th Edition does not have the beam section listed under the "light beam" section and neither does the WF section. I was not able to find it in the AISC Historic Shapes database either. When comparing other shapes it appears as if the section properties of a W18x40 would be similar.

Does anyone know where I can find information on a 18B40 beam section?

Thanks,
Katy

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[Harold Sprague]

If it was built in 1970, it was a W18x40.  The engineer was probably an old timer.  The B was indicative of a Bethlehem beam. 
 
Check out the references:
http://www.slideruleera.net/miscellaneous.html

Regards, Harold Sprague


 
> Date: Thu, 8 Oct 2009 16:49:29 -0700
> From: katy...@cox.net
> To: sea...@seaint.org
> Subject: QUESTION REGARDING 18B40 (LIGHT BEAM SECTION PROPERTIES)

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Hotmail: Free, trusted and rich email service. Get it now.

[Richard Calvert]

Please look at

http://www.aisc.org/content.aspx?id=21908

 

If you’re a member you can download the DB for free – I have it, but the file is likely too large to go thru the email…

and no, that isn’t necessarily a W18x40 – some time ago different manufacturers used differing nomenclatures.  I have an old 193x Carnegie steel book that uses similar nomenclature to this (I don’t have access to it ATM) but following their nomenclature that section may well be a 40” deep by 18” wide section.  And I believe they used B as well for wide flanges. 

 

Best to get the full (mostly) DB from AISC to be certain. 

 

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[Harold Sprague]

Katy,
You are going to have to measure the shapes in the field. 
 
Richard,
The AISC data base is for shapes currently constructed and contained in the AISC 13th Edition.  Katy indicated that this was constructed in 1970. 
 
Katy,
The AISC 6th Edition was in force from 1963 to 1970 when the AISC 7th Edition came out.  The convention of listing the depth and then the weight per foot was established before the 1950's.  In the 1950's the convention was to call out the depth, shape, and weight per foot (example 14 WF 43).  Plan steel shape designation was formalized in the AISC 7th Edition, p 1-10.  The example cited in the AISC 7th Edition is the "New Designation W14x26... Old Designation 14B26".  The practice was to list the depth in inches followed by the weight in pounds per foot.  Bethlehem listed designations in their 1940's literature with "B" and the AISC designations were "WF".  Later, AISC changed formalized the designation to for all member mills to "W". 
 
I worked for a steel fabricator, erector and detailer from the mid 1970's until 1980.  The company dated back to 1927.  The engineer for whom I worked started his career in 1950.  He taught me the old call outs as well as the new ones. 
 
According to the AISC "Historical Record....", the shapes with a depth of 18 inches had a minimum weight of about 46 pounds per foot through the early 1950's.  The AISC 7th Edition shows a W18x40.  The W18x40 and W18x35 are the same family and first came onto the market somewhere in the 1960's.  Per the AISC 7th Edition, the 3 mills that manufactured the W18's were Bethlehem, Inland, and US Steel.  The only manufacture making this particular family of W18's of which I am aware was Bethlehem in the early 1960's according to the US Steel and Bethlehem product literature. 
 
If the beam measures 18 inches in depth, has a 6 inch wide flange, a 1/2" thick flange, and the call out is somewhat correct, it is most likely a W18x40 manufactured by Bethlehem Steel. 

Regards, Harold Sprague


 

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From: Rich...@lbbe.com
To: sea...@seaint.org
Date: Fri, 9 Oct 2009 07:12:10 -0400

[Gary L. Hodgson and Assoc.]

Just to add to the confusion, Canada had one steel mill (Algoma Steel) producing wide flange shapes from the 60's through the early 2000's.
They produced a W18x40 which had a depth of 17.74", width of 7.44", flg t of 0.44" and web t of 0.3".  It was made in our 44W (Fy =44ksi) steel. To avoid confusion with the American W18x40 it was changed to a W18x41, in 1978 I believe.  It was never listed in the AISC steel manual but some American manufacturers (& the odd European mill) picked up those different Canadian shapes up after Algoma got out of the wide flange business in 200X.
Gary

[Mandeep Singh]

Hi all,

Can anyone tell  the reason behind the codal provision of taking the critical section for failure of foundation in shear at a distance of d/2( d=thickness of foundation slab) from the face of column for punching shear and at distance of d in case of one way shear.

 

Thanks & Regards.

 

Mandeep Singh

GET

 

 

------- Original Message -------
Sender : Richard Calvert<Rich...@lbbe.com>
Date : Oct 09, 2009 20:12 (GMT+09:00)
Title : RE: QUESTION REGARDING 18B40 (LIGHT BEAM SECTION PROPERTIES)