XR250
Structural
- Jan 30, 2013
- 5,763
I have a situation where we need to notch the top flange of a W8x21 flush beam for some immoveable water supply lines (1/2"ø). See attached. The notches will be within 32" of the support with a moment of about 9'-k at that point. The web will be packed out with wood on both sides to support 2x10 floor joists.
I have analyzed it assuming the notched portion is essentially a WT section (ignoring the un-notched flange). Using the section properties of a WT8x13 (which are a pretty nice fit - basically same web and flange), I get a bending stress of 27 ksi. If I assume I cannot get any local buckling of the tip of the tee due to the un-notched flange bracing it, then it should be compact and I can use an allowable bending stress of .66Fy. Does this approach sound reasonable? I checked deflection in my beam program by adding two short segments of WT section properties and it basically did not change. I am, also assuming I can ignore any twisting of the beam from the flange unbalance since it is framed flush.
Thanks
I have analyzed it assuming the notched portion is essentially a WT section (ignoring the un-notched flange). Using the section properties of a WT8x13 (which are a pretty nice fit - basically same web and flange), I get a bending stress of 27 ksi. If I assume I cannot get any local buckling of the tip of the tee due to the un-notched flange bracing it, then it should be compact and I can use an allowable bending stress of .66Fy. Does this approach sound reasonable? I checked deflection in my beam program by adding two short segments of WT section properties and it basically did not change. I am, also assuming I can ignore any twisting of the beam from the flange unbalance since it is framed flush.
Thanks