SIZING: Monster for glulam beam. Install garage door under load-bearing column

[Gamlehav]

Hello

I wish to install a 25x21 overhead door in the middle of the garage gable. See attached image.

Can I use the same dimension as the ridge beam that can handle a span of 5.8m? I believe so because it is only the weight of 2.4m ridge that will come through the pillar and over the garage door. But the difference is that the force is not distributed as over the ridge, but is centered directly over the 2.5m garage door.

I think it will work but it would be great if there was some tool online that can calculate it or maybe there's someone awesome on the forum?

Best regards

 

[NoOne2k]

What you need to dimension your beam for is a 32.217kN point load in the middle of the beam with a span of 2.5m. I seem to recall having seen tables for that type of load but can't find it right now.

 

[jonaserik]

A 45X145 on edge handles it easily and is on posts at the outer ends, a bit rough maybe, but better that than flimsy, only 2.5 m

 

[Gamlehav]

What you need to dimension your beam for is a 32.217kN point load in the middle of the beam with a span of 2.5m. I remember seeing tables for that type of load but can't find it right now.

Very well summarized!

 

[Gamlehav]

A 45X145 on its side can easily handle it and rests on posts at the outer ends, maybe a bit heavy but better that than too weak, only 2.5 m

Standing framing is extremely strong, but 3200 kg is a heck of a lot.

You might be right, but when I'm building the rest of the roof to withstand extreme snow loads, I was thinking of getting a table on this as well. I should probably call a manufacturer when I have more time.

 

[Staffans2000]

When I expanded, the local building merchant calculated the dimension of my ridge beam. They have computer programs specifically for that.

Staffan

 

[bossespecial]

It would require glulam 90x315 alternatively 115x225.

 

[justusandersson]

Glued laminated timber 90x270 can handle it, but I recommend 90x315. That way the deflection will be about 4 mm, which is good if you are going to fit a door under the beam. Construction lumber 45x145 is nowhere near being usable. There are some other stability and attachment issues associated with the construction that need to be addressed.

 

[jonaserik]

The general rule is incredibly strong, but 3200 kg is an awful lot.

Of course it is, I have personally placed a 45X145 on its side above my storage doors, 2.5 m wide with a roof slope of 25 degrees, and it holds well. If you're attaching a garage door to it, it might be thin. Glue-screw two next to each other and it will hold. The snow load in your region can't be that much, and it looks like your roof angle is greater than mine. Clearly, there are opinions on mine here on the forum as well, but there's no reason to exaggerate anything.

 

[tobbbias]

Of course it is, I myself have set a 45X145 on edge over my doors to the storage room 2.5 m wide and roof pitch 25 degrees, it holds well, then if you're going to attach a garage door to it, it might be thin. Glue screw 2 side by side then it will hold. Snow load at your latitude can't be of a larger amount and looks like your roof angle is greater than mine. Sure, there are opinions on mine here on the forum too, but there's no reason to overdo anything.

Haha, but do you have a nockbalk as a roof solution then?

 

[justusandersson]

A 2.5 m long 45x145 C 24 with a point load of 32 kN in the middle will deflect about 10 cm.

 

[Kane]

A 45X145 on its edge can handle it easily and rests on posts at the outer ends, a bit hefty perhaps but better that than flimsy, just 2.5 m

3-ton point load in the middle of one like that? Is that calculated correctly?

 

[jonaserik]

The one I placed is upright above the hole itself at the front edge of the door hole towards the gable, and the panel and the rafter are also attached to it. I have vertical paneling. Then it's possible to reinforce with an extra crossbeam further down to prevent the rafter from wobblying with the legs. In my case, it holds; if you're worried, let the beam extend all the way to the rafter and secure it, and perhaps use a slightly larger metal plate and anchor screws.

 

[jonaserik]

3 tons point load in the middle of one like that? Is it calculated correctly

If I'm not completely mistaken, a 3-ton point load is about 2 meters of snow on the roof, it takes a lot to reach that. What can happen is if the wind drifts so one side gets a lot that it can become a shear function (uneven load) on the roof, pressure on one long side.

 

[richardtenggren]

If I'm not completely wrong, a 3-ton point load is about 2 meters of snow on the roof; it takes a lot for that to happen. What can happen is if the wind drifts so that one side gets a lot, it can create a shearing function (asymmetric load) on the roof, pressure on one long side.

Have you not noticed the roof construction with ridge beam and pillar, where one of the pillars has to be bypassed? See justus' reply above...

*shearing/shear load?