Glue-laminated beam over two garage doors, two short or one long?

[Robban66]

Hi,

I am remodeling the garage, and above the two garage doors (which have about 50 cm between them) I am considering placing two glulam beams and setting them on glulam columns. It just occurred to me that it might be better to use just one long glulam beam and then support it between the doors with one or two columns.

What are the pros/cons of each option? How would you have done it?

 

[Mikael_L]

What do you have for loads above the doors?
Are the doors on the long side or the gable of the garage?

 

[Robban66]

They sit on the bearing side, the roof slopes front/back.

And the loads will be a metal roof with insulation, snow zone 3.5. I have checked which LT I should choose if I set one per opening, and it seems to work with 66x315 or 90x270.

 

[Robban66]

I can add that since the gate is supposed to be 2.125 m and LT at least 270 mm, it seems likely that I will place the hammarband directly on top of the LT beams. (If it makes any difference)

 

[injonil]

If you place a beam with 3 pillars, you can use a slightly smaller dimension for the beam. It's probably quite marginal though, so do whatever is easiest in my opinion!

 

[Mats]

If you can use a long beam, I would do that. It will be more difficult to get it up, but it will be somewhat stronger since you avoid the joint.

 

[Robban66]

The column load seems to be around 20 kN and 90x90 LT should work. If I glue/screw together two pieces of 120x45 as a column, will it hold or will it be too weak?

 

[Gabbe1]

The advantage of having a single long beam is that the beam practically behaves almost like it's fixed at one end (between the supports). This means that the same beam will bend less under the same load.

 

[Robban66]

I have decided to place an LT beam along the entire front edge. On one side of the door, it's just over 1.15 m, on the other around 0.4 m, and between them about 0.5 m, so it feels just as good to lay the beam all the way and place a horizontal joist above it as a wall plate.

 

[Mikael_L]

I don't see much point in letting the LT beam extend further to the sides than necessary. You get a more expensive beam, a beam that's harder to transport, heavier and thus more difficult to install, and more thermal bridging. The only good reason I can see is that the garage could be easily modified in the future regarding the number of doors and the width of the doors.

 

[Robban66]

Between the gates there it probably serves a function, that it becomes stronger with one beam instead of two?

But maybe it's easier to "splice" at both ends and place the stud on edge under the header instead of using the beam.