I will be installing a 3x18x24 ft glulam on top of two 3-stud columns, all per the engineers direction. But some of his direction is a little vague. I have sent him an email asking for clarification, but I thought I would post here also to see what the pros say. The columns will be almost 14 ft tall with bracing at the 8 ft level. Shouild I glue the studs together in additon to nailing? Should I use some type of Simpson conector to tie the column to the glulam?
Do it right, or do it twice.
Replies
3 1/8" wide gluelam, I would hand pick out stud/cripples. Two underneath, two King studs. I would Flat Strap backside, on both ends. I wouldn't use glue, thats just me. I just know, that, this is all resting on nice, concrete pads underneath. be Safe Jim J. do you have to cut out both top plates?, or can you leave them in place??
We are replacing a double 2x12 and extending it 12 ft. One end of the glulam will rest on an existing column buried in an existing wall. The other end will be on a column we will build, and it will be exposed for the lower 8 ft. There is no top plate on the 'new' end. The engr has spec'd 3 stud bearing, so two 2+2 like you say won't work. We could do 1+3, or fasten studs on three sides of the upper part of the column that won't be visible. Actually only two sides, because the glulam will run a little long. What do you mean by flat strap? The foundation is concrete slab on grade, and it was designed with columns at both points.
Do it right, or do it twice.
On my way home this evening, I thought to my self, wait a minute, is it a 24' span?, 14' in the air?, Elcid72, "please" let me back up, my glulam span charts only show up to 11 1/4", in a 3 1/8" glulam, with only a 10' span at 1000lbs, per lf. So that being said, I know a D.F. #1-4x4x10' will carry 5000lbs, D.F.#1-4x6x10' will carry 7850 lbs, note- post application only, and at 10' Max. height. Is there room to install, lets say 2- 4x4's, at one end?, I would be curious as to what the total load is, at each bearing point. Also, seems to me, that you might be better off using a 5 1/8" glulam, or 6 3/4" , try and shorten up that height, this would allow you to use a wider post underneath this. Best of luck. Jim J. flat strap, just a 2' wide x 18" simpson strap. your application may call for simpson, post to beam connector. JJ
Trust me, it's a 24 ft (maybe 23-6) clear span, the glulam is (nominal) 3x18, and the engineer has been to the site twice to take measurements. I asked about using a 4x4, and said he preferred 2x4's. At the price I paid him, I'll do it his way. I don't know what the actual loads are. It carries a ridge board for a cement tile roof. We are converting a flat ceiling to a vaulted ceiling.
Well, I was going to post a picture but I keep getting an error message.
Do it right, or do it twice.
I am pretty sure the connector you need is based on what seismic zone you are in, ElCid. We use glulams alot up here and for the connection you are asking about we'd use either a standard Simpson column cap "CC31/4-4" or "CC31/4-4 rotated". The first numbers indicate the width of the beam pocket on top, the number after the dash indicates the callout size of the post. The standard configuration is for the steel flanges for the beam through bolts and the post through bolts to be perpendicular to each other once installed. The "rotated" option is designed so the through bolts are all parallel when installed, which is nice if you're trying to fit that connector inside a framed wall.
Also, we are required to use solid posts here, usually 4x6 for a 31/8" beams, but occasionally we do use 4x4s - definately not 2x4s or 2x6s nailed together. As for glue...I don't think any common glues gain you any structural strength - I think that's pretty much factory domain. I certainly wouldn't trust any construction adhesives or epoxies to give any structural help.
But like I said in the beginning, we could easilly be in a more seismic sensitive area. We do get earthquakes fairly regularly and local building codes require so much flippin' hardware and hold downs that buildings are weighed down from the shear weight of them all. For example, these Simpson column caps are standard on the shelf hardware at most lumber yards, and special ordered caps are usually a week out at the most.
Cement Tile Roof? 24 foot span? 3" wide beam? WOW!!!!! I am not an engineer but that seems like a light beam. Then again I live in snow country and sometimes think in terms of 50 to 100 pound snow loads. Even tile is not 100 pounds, I guess.
Say ELCID72, are you building this structure on your own? Are you doing the work?
If so how did you get that beam up there? Was it easy to rent a lift of some kind?
"If so how did you get that beam up there? Was it easy to rent a lift of some kind?"
I know you weren't asking me, shaker, but here's a photo of my 140 lb son lifting a 6x12x24' glulam by himself. Sorry, couldn't help myself - sure proud of that kid.
There will be three of us, and we will be using a Genie crank-up lift tthat looks kinda like a fork lift...some times used to lift metal duct. I think the beam will weigh about 380#. We have almost no seismic requirements here. Sill plates are anchor bolted to the concrete every few feet, and then...that's it! No requirtements for any other hardware. We're too far south for tornados, too far from the coast for himmicaines, no shaky earth.
Here is a pic of part of the work area. The room in the foreground-right has a vaulted ceiling; the rooms to the left have a flat ceiling. The goal is to take out all interior walls and the center column, and make the entire ceiling vaulted. The underside of the ceiling ridge is almost 11 ft, then there's a 2x12 ridge board, then the glulam. The resulting room will be about 24 ft square.
Do it right, or do it twice.
Edited 8/14/2003 4:47:25 PM ET by ELCID72
why don't you ask your engineer what connectors he wants spec't? I'd want him signing off every thing to do with that beam and how it ties to the foundation and transfers the loads. that is what you are paying him for.
You're too late, I talked with him Friday. He says no post-to-beam connector is needed, just brace it to the roof purlins and collar ties and adjacent walls, and whatever else is handy. Part of his contract calls for a site visit after the beam is in place to verify it's ok.
Here's a pic I sent him asking for clarification. The question was...the roof area over the current sloped ceiling is 'clean' whereas the roof over the flat ceiling has purlins (or strongbacks) and diagonal bracing to the bearing wall...does the new sloped ceiling need the braces? He said he would like to see purlins under the entire roof, and it would be a good place to shore the roof durting the change.
Oops...have to find the pic...see next message.
Do it right, or do it twice.
Edited 10/16/2003 10:09:00 PM ET by ELCID72
hee's the picture of the existing condition above the ceiling...
Do it right, or do it twice.
Edited 10/16/2003 10:09:47 PM ET by ELCID72
good enuff. put some kickers on the ends of that gluelam so it can't roll while your loading it. wouldn't hurt to brace the center so it stays vertical and true... you probably already knew that.
hub
Oh yeah...I already knew all that stuff...I just post here for fun. Keep the cheap advice coming folks, I read it all.
Do it right, or do it twice.