Bending Class of Reinforced Steel Beams

[murphy89]

Hello, I am working on reinforcing steel beams for new, higher loads. For steel beams, the bending class determines if you use the plastic section modulus (Z) or the elastic section modulus (S). How can I figure out what the bending class of my new reinforced beam is? I've read through the steel code (S16, I'm in Canada) and all I see is a table for ratios of b/t and h/w but that doesn't really apply when the section is reinforced. I'm using two methods which are adding rods either side of the web just inside the flanges, and adding a WT to the bottom of the beam.

Thanks

 

[CDLD]

Are the rods doubly symmetric, ie., 4 total?

The WT will lower the neutral axis, which means compression over a longer portion of the web (more likely to have issues with local web buckling).

The S6 bridge code, has guidance on the web section class.
Refer to:

- Bending – CISC-ICCA

QUESTION: (SUMMER2016) I am proportioning a mono-symmetric I-girder whose web-slenderness, h/w, marginally satisfies the Class 3 limit for W-shapes in pure bending in accordance with Table 2 of S16-09. Does this limit apply to mono-symmetric sections? ANSWER: No, the limits for I-sections are...

www.cisc-icca.ca

Flange classes will be the same as regular W beams in both your reinforcing options.

Do you have any flexural compression on the bottom flange?