huangyhg

battenning steel members together
dear all,
i am looking to create a compound beam by battenning together two 'i' section beams. the usual detail is to provide a number of steel plates which are welded across the top and bottom flanges of the beams in order to batten them together.
my question is; can i use plates which just fit between the flanges and are welded to the flange edges, rather than having plates which fit right across the entire breadth of the flanges. does this detail give sufficient lateral stability to the flanges (assuming that these batten plates and their welds can carry 2.5% of the flange force)?
regards
andy
andy,
the stability issue, assuming i understand your intent, will depend upon the width of the plate connecting the flange edges. for no particular reason other than it seems reasonable, if the width of the connecting plate is no greater than the width of the two flange halves, i would see no big stability issue. this is calculable, but probably not worth the effort. the welding (i assume it will be continuous, complete penetration)will act somewhat as a longitudinal stiffener. if you put a stiffening gusset in before you put the connecting plate onto the flanges, you could resolve any stability issues you might have. make sure your welders have small hands!
ron
ginger
would about the practical implications of what you are trying to achieve? what is the width of the connecting plate? i imagine if it's quite narrow it be difficult to actually hold in place whilst welding. (resulting in greater labour costs.)
mind you, i never seem to get out of this office to see these things being done.
regards
kjj.
ron & kjj
thank you for your thoughts, i needed someone's rational thinking to ensure that this is feasible. you have correctly envisaged my problem and the advice tallies with my owm thoughts. i will now go and round up my army of dwarf welders to get into the gap and carry out the welding !!!!!!
best regards
andy
the generally accepted method is to connect the beam webs at intervals with bolts passed through pipe sleeves. this provides a rigid spacer between the beams and ensures lateral stability if the bolts are spaced less than the lb of the the beams and placed 3 inches below the the top flange. it also avoids the cost of vertically challenged welders.

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