glulam splitting water damage large commercial hardware building
glulam splitting water damage large commercial hardware building
(OP)
5 1/8 x 18 glulam splitting at hanger bolts due to water damage... must remove entire splitting protion and replace with new glulam... (too far away from post for a cantilvered saddle splice... dont want to break into floor for new foundation directly under splice)
any thoughts as to the best fix?
current solution is to sandwich the splice with steel plates, lag em in with how many it takes to counter moment at the splice point (splice is about at 1/3 point).. splitting problems? bolting into side of glulam issues... load is say 400 # ft and span is 30 feet (splice at say 10)





RE: glulam splitting water damage large commercial hardware building
Must be an older glulam as most now are made with a waterproof glue.
Mike McCann
MMC Engineering
RE: glulam splitting water damage large commercial hardware building
The Design issue is the splice point of the old and new glulam beam after the entire portion of the existing glulam that is cracked is removed and replaced.
RE: glulam splitting water damage large commercial hardware building
RE: glulam splitting water damage large commercial hardware building
RE: glulam splitting water damage large commercial hardware building
A column is being added, but ofcourse its only for backup because we dont want to have to prove that the 4" slab can take the load - wont work. SO! the question is really the plate...
as of today... design is for sandwiched 1/4" plate (16"x80") with THIRTY TWO 5/8" thru-bolts to develop the required moment.
additional comments? hasnt anybody every spliced a glulam like this?
thanx for replies!
RE: glulam splitting water damage large commercial hardware building
If so, 5/8" holes are going to kill your net section checks....
Just my concerns to try and get this thread going. Its interesting, but I'd go with a new beam....or bust that concrete up and pour a footing to support a new post.
RE: glulam splitting water damage large commercial hardware building
well, i read last post ... good concerns...
if i am thinking about this correctly, actual load analysis gets pretty hairy involving calculating net section reduction and implications.. but, in my mind i have replaced the missing wood holes with certainly an equivalent strength of (2) 1/4" plates and the bolts?? so, as long as the compression developed by the bolts into the wood does not exceed the allowable for the lams then shouldnt it be ok... !!?? the plates can take the shear im sure. all that has been done is a simple how many bolts does it take about the splice to resist the moment in the beam at the splice....
The acutual loading on the bolts is hard to visualize.. but i think the direction of the loading slowly changes as you start from the splice and go to the end of the plate, as well as as you go up or down the hieght of the beam... at any case i think it is not directly up and down... which might blow out my simple moment calculation....
which brings another question... i have the plate in the middle of the beam... maybe it would be better to have it skewed to the tension side of the beam? does it really matter?!!
off to the overthinking races!!!!!????
RE: glulam splitting water damage large commercial hardware building
RE: glulam splitting water damage large commercial hardware building
Get your moment at the splice and resist with a couple from a row of bolts in the extreme laminations? Then your connection from bolts is direct tension/compression(theoretically at least). You'd have to consider group action factor per nds if you go over a 1/4" diameter connector.
Back to the net section checks, your load doesn't fully develop into the splice plates till you get to the inner most row of bolts. So the top and bottom laminations still have to carry alot of the load for the first couple of bolts or so, which you are removing a significant amount of lumber from predrilling the bolt holes.
This would be my best guess. No expert with this sort of problem, I'm just trying to get some talk going.
I'd love to hear what others think about this line of reasoning so don't hesitate to criticize.
RE: glulam splitting water damage large commercial hardware building
RE: glulam splitting water damage large commercial hardware building