re galvanizing of reduced beam sections 9rbs0
 

re: galvanizing of reduced beam sections (rbs)
i remember seeing a question with regard to galvanizing of reduced beam sections. i cannot recall who posted the question nor where it was posted (which forum). the keyword search portion of eng-tips is not working at the moment. so, if anyone can remember who posted that question and where, please pass this information along.
with regard to rbs galvanizing. i had a chance to attend a seminar on omf and smf frame design, fabrication, and welding this last week. i spoke with tom sabol about the subject of galvanizing rbs flanged beams. tom referred me to robert shaw of structural steel technology center, inc.
robert was of the opinion that there wouldn't be any particular problem in galvanizing rbs beams with two exceptions.
first, a grinder should be used to remove any embedded hydrogen in the area of the reduced beam flange cut. all that is needed is a light grinding of the surface. a surface finish of 500 microinch is adequate.
second, (and this seemed to be more important), the rinse following the pickling process should be used to remove all acid (hydrogen ion) from the surface of the rbs beam. a good amount of time in between the pickling / rinse process and the actual hot-dip galvanizing should be permitted. how much time is a matter of judgment. it primarily depends on how effective the rinse is following the pickling (acid bath) process. to be on the safe side, i would think 24 hours should be sufficient.
i hope this post is useful and timely .
tower engineer,
i've been trying to find information on the behaviour of rbs in bending. in particular reduced beams with the flanges cut on one side only ( creating something like a c section).
can you refer me to any info.
just a thought about non-concentric rbs: the fact that the rbs is on concentric should not effect the behaviour of the beam up to the point of yeild. beyond the yeild point, we should expect a non-concentric section to behave differently than that of a concentric section.
the question you should ask yourself is: does it matter to you what happens to the section after the point of yeild? is there a concern for satisfying the life safety issue for a non-concentric beam section in the plastic state?
-richard l. flower, p. e.