Hello,
I'm building a house with träullit, and we've reached the point where the trusses are on and the roof is being laid.
I have 2 openings of 5000mm x 2300, where on one of the openings the trusses are resting on a cast beam, and the architect thinks I should have a pillar in the middle, which I don't want.
I have cast in träullit (that's how you do beams in träullit).
Originally, the cast part was dimensioned L 5000, width 100mm, and height 100mm, with 4 pieces of 14 mm rebar at the bottom.
Now I've modified it a bit to Length 5000mm, width 1600mm, and height 100mm, with 4 pieces of 16 mm iron at the bottom, and 2 pieces of 12 mm higher up in the beam. What do you think about that?
Could someone calculate how much more load this beam can handle under pressure? My architect can probably do this too, but I'm really excited to see if this works, which I obviously hope for. Planning to install folding doors in the sections, and it would be fun if it's possible to open them when everything is completed.
I'm building a house with träullit, and we've reached the point where the trusses are on and the roof is being laid.
I have 2 openings of 5000mm x 2300, where on one of the openings the trusses are resting on a cast beam, and the architect thinks I should have a pillar in the middle, which I don't want.
I have cast in träullit (that's how you do beams in träullit).
Originally, the cast part was dimensioned L 5000, width 100mm, and height 100mm, with 4 pieces of 14 mm rebar at the bottom.
Now I've modified it a bit to Length 5000mm, width 1600mm, and height 100mm, with 4 pieces of 16 mm iron at the bottom, and 2 pieces of 12 mm higher up in the beam. What do you think about that?
Could someone calculate how much more load this beam can handle under pressure? My architect can probably do this too, but I'm really excited to see if this works, which I obviously hope for. Planning to install folding doors in the sections, and it would be fun if it's possible to open them when everything is completed.
You need to provide more input. Measurements, drawing. It's impossible to calculate without knowing the loads.
If I were to guess without knowing more, I don't think your proposed beam can support more than its own weight. Definitely not any roof load.
With your proposal, you are doubling the span. Then the stresses increase fourfold, and the deflection increases 16 times on the same section. You increase the reinforcement by 100% (the number 12s higher up help very little). If your long beam is to be feasible, you must increase the height significantly, perhaps 3-4 times higher section.
If I were to guess without knowing more, I don't think your proposed beam can support more than its own weight. Definitely not any roof load.
With your proposal, you are doubling the span. Then the stresses increase fourfold, and the deflection increases 16 times on the same section. You increase the reinforcement by 100% (the number 12s higher up help very little). If your long beam is to be feasible, you must increase the height significantly, perhaps 3-4 times higher section.
Consider increasing the height of the beam instead. You only need to increase by 3 cm to double the strength (since the height of a beam increases strength cubically). Without thinking about it, it seems all too weak with only 4 pieces of 16 mm iron that are supposed to take all the tensile forces. With a load of, let's say, 500 kg, it can put a tensile load on the 4 pieces of iron of 15-20 tons. I wouldn't want to subject steel to that tensile load. I built with HE beams in steel. They are easier to calculate and significantly more durable. I suggest starting with HE 140. How much load will there be on the beam and how is it distributed?
BAS said:
What do you mean by strength?
It is the stiffness that increases with the cube, strength increases only with the square of the height.
Note that with the same section, the deflection increases 16 times, i.e. to keep the deflection constant, the stiffness must also increase 16 times!
The deflection thus increases with the fourth power of the length!
Hello again,
I looked into it more today, and one of the openings has no roof truss, but a gavel peak that I estimate weighs up to 1500 kg. On the other, 3 roof trusses rest, and I have been suggested to place a glulam beam, which should be joined with 1 roof truss on each side.
I will come up with a good sketch.
I looked into it more today, and one of the openings has no roof truss, but a gavel peak that I estimate weighs up to 1500 kg. On the other, 3 roof trusses rest, and I have been suggested to place a glulam beam, which should be joined with 1 roof truss on each side.
I will come up with a good sketch.