Bearing Eccentricity

[JStructsteel]

Have a wood joist girder bearing on 6" stud column. (15K DL and 18K LL) What eccentricity would you use? I was thinking 1/3rd bearing width.
Also, would you provide a steel plate for bearing with a high load like this?

 

[BAretired]

One idea would be to calculate the slope of the simple beam, then apply a moment to the column which would match that slope.

BA

 

[KootK]

- I was going to recommend the same approach as BA for "serious" situations. Obviously, the amount of eccentricity in the column depends on the relative stiffness of the two members coming into the joint. If you have a very stiff beam for deflection and a fairly slender column, which is often the case, the column may well flex into a position that reduces the effective eccentricity.

- Previous statement excepted, I will usually do this quick and dirty rather than rigorous and, when I do, 1/3 bearing is precisely what I do. It's not an identical situation but the 1/6 width eccentricity commonly used for stud wall design provides a meaningful data point for comparison I think.

- Sometimes I will take the counter-intuitive approach of ensuring that sill plates are installed between the post and the beam. I don't believe in perpendicular to grain wood crushing as much more than a serviceability thing and I like the idea of having a softer material in the mix to even out the bearing stresses, somewhat like a bearing pad under a precast beam.

- I would be inclined to provide a steel plate for bearing so as to make bearing stresses at least work by the numbers +/-

 

[JStructsteel]

Thanks guys, answers right up my thinking alley.