Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here


steel load limits

steel load limits

steel load limits

I need to know for a generalized estimate "how to figure a load limit for say a W8x18 wide flange beam?

RE: steel load limits

There are generalized load tables provided in the AISC manuals.  For instance, a W8x18 (36 ksi) can carry a total uniformly distributed load of anywhere from about 12 kips to 54 kips, depending upon the span.(ref. AISC ASD Manual 9th Edition)  

There are several variables you have to consider such as the unbraced length, the span, the allowable deflection, bending, shear and axial loads (if any).  If your conditions do not exactly fit the load tables, you must compute the stresses in the beam for each condition.  An example would be a non-uniform load, a concentrated load, or other conditions.

Most libraries have a copy of at least one of the variations of the manuals.  If you are near a University which has an engineering program, you can likely get a copy of one of the manuals from their bookstore or you can order online from a variety of sources, including the American Institute for Steel Construction (AISC) at www.aisc.org

If you are considering this for anything other than estimating purposes, please get a licensed structural engineer involved.


RE: steel load limits

There is not a single amount of load that a W8x18 beam can take.  It depends upon the span and the amount of lateral bracing present along the span.

The AISC Manual (both ASD and LRFD) provides beam tables for wide flanges.  The tables provide max. uniform loads (kips/ft) for beams assuming they are totally laterally supported.  This means that there are braces attached to the beam which prevent sideways movement of the compression flange, or some type of torsional restraint.

The AISC Specifications provide more detail in calculating the maximum load for a beam with unbraced lengths.

RE: steel load limits

If the beam is a W8x18, it comes in two stress levels now 36 ksi and 50 ksi.  Most beams now are 50 ksi.  Could you make a mistake here?  Maybe not as described above with the selection of the section because if you choose A36 you will certainly be OK if it is a 50 yield beam, but what about the connections: number of bolts, length and size of weld, copes, size and thickness of endplates or clip angles...if the beam is the right size, are you OK?  Maybe.

RE: steel load limits

The connection does depend upon the yield of the steel beam.  Primarily, the bearing of the bolts on the web holes would be the most affected by the beams steel yield and the possibility of the rupture of the web would have to be checked.

The bolt shear, clip angle bearing and shear, and connection of the clip to the supporting structure would not be affected.

RE: steel load limits

 I think not only the section dimensions but also the support conditions are important when considering the capacity of this section.The 'Manual' will help as well but it won`t take the conditions like e.g. fork supports into account,so the strength of the section is not the only parameter.
 Greetings from Turkey.

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members! Already a Member? Login


White Paper - The Criticality of the E/E Architecture
Modern vehicles are highly sophisticated systems incorporating electrical, electronic, software and mechanical components. Mechanical systems are giving way to advanced software and electronic devices, driving automakers to innovate and differentiate their vehicles via the electric and electronic (E/E) architecture. As the pace of change accelerates, automotive companies need to evolve their development processes to deliver and maximize the value of these architectures. Download Now
White Paper - Model Based Engineering for Wire Harness Manufacturing
Modern cars, trucks, and other vehicles feature an ever-increasing number of sophisticated electrical and electronic features, placing a larger burden on the wiring harness that enables these new features. As complexity rises, current harness manufacturing methods are struggling to keep pace due to manual data exchanges and the inability to capture tribal knowledge. A model-based wire harness manufacturing engineering flow automates data exchange and captures tribal knowledge through design rules to help harness manufacturers improve harness quality and boost efficiency. Download Now
White Paper - Modeling and Optimizing Wire Harness Costs for Variation Complexity
This paper will focus on the quantification of the complexity related costs in harness variations in order to model them, allowing automated algorithms to optimize for these costs. A number of real world examples will be provided as well. Since no two businesses are alike, it is the aim of this paper to provide the foundational knowledge and methodology so the reader can assess their own business to model how variation complexity costs affect their business. Download Now

Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close