S-shape I beam allowable moment 1

[happye]

Hi new engineer here that forgot most of his schooling.

I'm working on verifing loads for monorails and I have some S8X18.4 and S10X25.4 and require the allowable moment. I have the aisc ninth but the graphs only include W and M beams. Can someone help me out and point me in the right direction?

 

[jberg]

For the allowable moment, you can look at Chapter F of the Specification, I believe. There are 3 equations, the one I remember is (12,000 * Cb) / (Lb * d/Af). I assume Cb = 1.0, Lb is the unbraced length in inches, and d/Af can be found in the properties section (1st part of book).

Since you are working on a monorail, I would recommend getting a copy of CMAA Spec. 74. It covers underhung monorails and deals with the local bottom flange stresses from the trolley wheels. Depending on the loads, the bottom local flange stresses can be very significant. It is a good read for structural and non-structural info related to monorails.

Joel Berg

 

[racookpe1978]

Shapebook 3.1 has the properties you're looking for, plus other standard and old (historical) shapes from mills that are out of business: From the "About" file on my copy:

ShapeBook is a productivity tool for quick access to the detailing dimensions and design properties of steel shapes. The data contained in this version of ShapeBook is based on the AISC Manual of Steel Construction LRFD, 3rd Edition. Structural steel shapes are available in US Imperial and Metric units.

South Fork Technologies, Inc.
1231 S. Toutle Rd.
Toutle, WA, 98649
Phone: (360) 274-0493
Fax: (360) 274-6105

http://www.southforktech.com

sales@southforktech.com

 

[racookpe1978]

See these files:

 

[racookpe1978]

S8x18.4 properties: