Concentrated load on web of beam 6

[helfreco]

Hello,
I am dealing with a beam in bending. In addition to the strong axis bending, there is a tension cable anchored to the web of the beam imparting a large concentrated load on the web of the W section. I am concerned about strength/local deformation of the web
I have not been able to find a guide showing how to analyze concentrated loads normal to the web. Has anybody else encountered this? I was trying to find something analogous like prying action or concentrated loads on a flange, but thought I would ask if anyone else has dealt with this.
Thanks!

 

[rb1957]

A picture would help understand.

A local doubler, or a fitting, to distribute the point load over more of the section.

another day in paradise, or is paradise one day closer ?

 

[DrZoidberWoop]

Page 9-14 of the AISC Steel Construction Manual has a new section titled "Plate Elements Subjected to Out-of-Plane Loads." I've used it quite a few times already for justifying load capacities on W-section webs and HSS flats. You're going to be looking for either equation 9-29 (nominal punching shear) or 9-31 (yield line approach to weak axis flexural strength). It's pretty straightforward and simple to follow. I think it loosely builds on the equations on pg 3.6-9 of Blodgett's classic book on welding structures.

See pages 17-19 of this AISC document for a full explanation from them, with equations and illustrations if you need them.

https://www.aisc.org/globalassets/modern-steel/archives/2019/2019_02_pdf.pdf

 

[msquared48]

Sounds like you need to consider torsion and add web stiffeners that would also reinforce the flange. Doubler could help too if needed

Mike McCann, PE, SE (WA, HI)

 

[msquared48]

Could you add another beam transverse to the original beam at the point of load to help tale the load?

Mike McCann, PE, SE (WA, HI)

 

[KootK]

Nice contribution DrZW. I wasn't aware of that resource.

 

[DrZoidberWoop]

I should qualify my post. I was referring to the 15th edition of the AISC manual.

 

[rb1957]

would "strong axis" bending be due to an out-of-plane load or an in-plane load ?

another day in paradise, or is paradise one day closer ?

 

[helfreco]

DrZ, that is exactly what I needed, thank you! I was aware of yield line analysis and was really hoping someone had already gone down that road for this situation since I was dreading deriving it myself. And thanks for clarifying the manual edition, I am still using the 14th in my office (this is not in the 14th edition). Sounds like it is way past time to upgrade.

msquared, no I cannot add a transverse beam. It would get in the way of the anchoring cable. There are also sheaves some space away to direct the cable somewhere else. I have to rely on the web to take the anchor load. I can add stiffeners, but I was looking for a way to sharpen my pencil before just adding steel to the system.

rb1957, yes, strong axis would be out of plane, like normal beam bending. This is my operating live load. The anchor load attached to the web of the beam is acting transverse, or in plane with the beam.

 

[rb1957]

I guess because a W section, not a typical I beam ?

another day in paradise, or is paradise one day closer ?

 

[NorthCivil]

Situations like this are why if I was stranded on some sort of an "engineering" deserted island, I would rather be left with Solidworks than E-tabs, its much more useful for these funny things.

Or maybe its a self fulfilling prophecy of the kind of engineer I've become and thus the type of work i find myself stuck into... I've never designed a primary structure taller than 4 stories (though ive designed plenty of bits and pieces attached to real tall ones!)