S beam secion details

[RBPrice]

Attached is a dwg. depicting ALL of the dimensions of S steel beam cross sectional details. Notice that it includes the fillet radius and the location where the fillet radius begins as well as the corner radius on the outside of the flanges.

Does anyone know of a chart that has ALL of those dimensions on it. I have found dozens of charts on the web but NONE of them have the complete details of the sectional profile.

Thanks very much.

Bob Price

AISI S SECTION .jpg

[JAlberts]

Unfortunately, the detail dimensions you are seeking are not defined by the various ANSI, ASTM, etc standards for hot rolled I-beam and other structural shapes. This leaves these feature dimensions to the discretion of each individual manufacturer. If you can decide on a potential specific supplier, you might be able to get the detail dimensions you require.

Otherwise, as I have on occasion, it is simply a matter of going and measuring an available item; even so, you must keep in mind that in hot rolled shapes the flange tapers, radii, etc are not closely controlled. As an alternative, utilizing WF (wide flange) beams because their flange inner faces are not tapered but are parallel with the outer flange faces can help make designing easier.

[RBPrice]

Thanks for the response.

First, I am aware that S sections are not often used but some people do and I want to create a 3D library of S shapes. The models would be used to get some idea of the suitability of the chosen shape to support a load or structure and as you quite well know, the details of the corner radii are critical to the stress loads on the beam. Since someone has to make the rolls that are used to make the beams, they have to know what those dimensions are, per AISI standards, in order to make the rolls.

I doubt that structural engineers go out to the steel supplier's yard and take measurements so they can be sure their bridges and buildings do not collapse. One supplier, ArcelorMittal in Michigan, from whom I got the diagram, told me they make their S beams in France but other than that, they were not able to get me a chart of the dimensions. That begs the question of why ASTM A-6/A 6M-05A does not publish all the dimensions: how do they check for compliance if they haven't published the dimensions.

Again, thanks for the reply

Bob Price

[JAlberts]

In reality, the radii of the corners at the web and and flanges is not really a critical element in the loading design of the beams since the design calculations for these beams are based upon the minium required thickness of the web that is specified by the various ASTM, etc standards which assume a sharp cornered intersection at the web and flange connection and take no credit for the added fillet material for shearing stress at that junction.

[RBPrice]

WOW - that is a revelation to me: that the analysis assumes a sharp corner. If I ran an FEA analysis with sharp corners wouldn't that show some unacceptable stresses in those sharp corners? So the purpose of the radii in the corners is just to avoid sharp corners on the forming rolls used to make the beams? I would very much agree that the radii on the external corners of the beams is not a factor but the interior corners would seem to me to be critical. Or is this methodology a way of building a very large safety factor into the analysis: sharp corners with a stress level one fifth of the allowable design stress are OK since in reality there is not really a sharp corner?

I recently designed some special lifting hooks for a very expensive device and I went to a lot of trouble to eliminate any sharp corners.

Thanks Mr. Albert

[JAlberts]

Including radii at inside corner junctions is definitely a good design practice for eliminating potential stress concentrations in any design.

With regard to the I-beams, you have to consider the fact that these beams are designed to loaded vertically or longitudinally which does not create transverse bending stresses at the web/flange junctions.

The critical design element in I-beam and WF beam applications is that the allowable longitudinal bending yield and tensile stress in the flanges is not exceeded and that the specified web thickness on the beam is sufficient to prevent its buckling under the compressive stresses imposed by the flanges under the longitudinal bending loads. At the same time, in the design of any localized vertical loading at some point along the beam the designer must insure that it is designed so as not to impose localized buckling of the beam at the point of loading.

[RBPrice]

At the risk of upsetting you, you should be aware that steel beams and other like hot rolled steel shapes are not the exclusive province of buildings and bridges. They are extensively used in the construction of all kinds of complex and very heavily loaded structures from off-shore drilling rigs, special purpose production machines, ships, docks, oil drilling equipment, space launch pads, pieces and parts of construction equipment etc., etc. etc. Those applications load the profiles in torsion, high impact loads, high temperatures, cold temperatures, shock loads from have large pieces of stone dropped on them, occasionally high caliber automatic weapons fire and even some laser guided missiles once in a while.

[JAlberts]

Don't be concerned about upsetting me since I view all dialog on technical and engineering issues to be strictly professional nature and as opportunities to exchange information and viewpoints and potentially learn from them. I do not intend to represent myself as an expert on the application and structural design utilizing structural shapes.

My comments on the radiusing was intended to convey my background knowledge of the principles on which the general standards on I-beams are based and not intended to minimize potential benefits of the existing radii.

That being said, my input on this subject is based upon 10 years (of my 40 years of mechanical engineering) of the design and construction management of petroleum offshore production and tanker loading facilities as well as additional experience in utilizing structural shapes in oilfield reciprocating pumping unit structure designs, so I am well aware of the multiple applications and loading conditions that structural elements can experience.

As far as eccentric loading on these beams, in good designs, any time there is a perpendicular load being applied to the beam that would result in a significant torque effect then the connecting element is notched in a manner that provides a welded connection to both the flange edge(s) and the web face which prevents an actual lateral bending stress at the web/flange joining line. Also a general longitudinal twisting of the beam still does not impose a lateral bending along the web/flange joining line.

[RBPrice]

Well Said - and I should have expected that someone with an address in Houston might know a thing or two about off-shore equipment.

Bottom line is that, thanks to you, I know more about the significance/impotance of the radii in steel beam shapes. I have found some data on WF beams that do include the corner radius so that is good: I can proceed with creating the profiles for them.

Thanks very much your comments and information.