allowable flexural strength of a beam web

[Grizzman]

I am designing a horizontal truss.
The chords are W18x46. the perpendicular web members are W10x22. the diagonal web members are 5/8" dia. rod.
the rods connect through the center of the web of the W18 between 6" -10" from either side of the perpendicular web members.
The rod has a maximum vertical component of 4.1 kips.
I'm trying to determine if the web of the W18 is strong enough to distribute the rod load over the beam section without distortion and/or what to do to alleviate such a problem, if it exists.
I've considered comparing it to plastification of a tube chord face(section K4 of AISC13) and considering it as a plate member in weak axis bending with l=ho=17.5" and each end fixed.(section F of AISC13)
a point in the right direction or reference to a design guide would be great.
thanks.

 

[msquared48]

Bear with me here as my answer may seem a little off your question...

The condition/connection you are describing seems very similar to that of a vertical W or H pile with a tieback. In my region, the detail for the rod used to show the rod penetrating the W or H pile to the side of the web causing an eccentricity to the steel pile member. Now, some engineers are cutting a portion of the web and flange out and welding in a section of steel pile thropugh which the rod can be inserted, thus bearing on the pile pile and W or H section concentrically.

Could this type of connection for your tension rods in the truss be applicable here to solve your transfer problem?

Mike McCann
McCann Engineering

 

[civilperson]

If the load case reverses, can the rods withstand compression forces?

 

[UcfSE]

You could add a stiffener and be done with it.

 

[Grizzman]

the rods are tension only.
stiffeners won't work. the rod penetrates the web and sets on a hillside washer. I could use a large plate washer i suppose, but I'm still pondering how to calculate if its needed.
If it is, you still have to consider the effects on the web at the edge of the washer.