Wasn't there a bigger difference between HEA and HEB? Maybe it makes more of a difference on larger beams and where they are used as columns, but I seem to remember roughly halving the cross-sectional area as the difference between them. :S
dagodo said:Now I have gathered a lot of information and contacted a structural engineer who helped with advice. The total span is 4735mm. After calculating all possible loads that may arise (according to the building regulations), the total load was 15.6 tons. Moelven recommends a maximum deflection of 7mm at such a span. I have calculated 6mm. IN THAT CASE, it will be an HEA 300, HEB 280, or an IPE 360. To support the load, I considered using glulam as it looks nicer and withstands heat better. The glulam columns will be 115x115, capable of handling a load of up to 93kN. The columns themselves will also be side-stabilized with the timber walls. The foundation will be redone and reinforced underneath. I can come back when it is finished
It sounded like a significant beam for that opening. Planning to create an opening of 7.2 m without a support in the middle, and my designer has calculated a HEA 220. In Luleå.
Nah, there was a bit of a difference between HEB and HEA. I can also go with a HEB 260. We'll see what's available. Now it is calculated based on the total snow load (i.e., half the extended roof area + 1/4 of the original roof area + a potential snow pocket = total snow load in the absolute worst-case scenario) + wind load (calculated for a wind speed of 25 m/s over an area of 36 square meters) + total dead weight (for the extension, it will be a metal roof, and eventually, I will replace the old roof as well, then I will reduce the weight by 44%). I will probably arrange for the two interior walls in the extension to lead some weight down to the foundation as well. Just place a few posts underneath. And this is not counted in. So sure, eventually it might be a bit over-dimensioned. jeppeknaster - what maximum allowable deflection has your engineer calculated? From what I understand, there are no strict rules about this, rather it's based on experience and intuition that many go by. If I allow a deflection of 10 mm, I can reduce the dimension significantly.
I installed an approximately 5-meter-long HEA 180 to transfer the load from a load-bearing wall. Two 45x120 beams screwed together are used as columns at each end. The engineer who did the calculations said that HEA 160 should actually suffice, but since the difference from 160 to 180 isn't significant, we chose the latter.
House in southern Norrland, 1.5 stories + basement, 45-degree angle roof with tiles on it.
House in southern Norrland, 1.5 stories + basement, 45-degree angle roof with tiles on it.
Regarding fire protection. According to "my" designer, you don't need to fireproof steel beams in a single-family home. A single-family home is usually just one fire compartment. Then again, it's another thing if you might want to do it anyway.
Ollebergkvist: I'm getting closer to your solution. I found a square beam KKR180 at my neighbor's. He was able to help me cut it to the right length. The beam itself is approved for maximum allowable deflection. In the worst-case scenario, it would bend 13.2 mm and the maximum allowable deflection is 15 mm. Since I have a bathroom upstairs, I don't want too much potential for movement. It just feels better that way. So my neighbor is going to weld in a straight piece in the middle along the entire beam, which will make it look like it has two compartments to further stiffen it. The advantage, besides getting a beam for a song, is that the weight is halved, from over 300 kg to 160 kg. It's my columns I'm considering whether I should also use steel there. For now, I've excavated and redone the old foundation, cast footings under today's nonexistent foundation, and then I've cast the footing and will soon build the second level with leca. So it's getting closer
I don't know the wall thickness in your neighbor's beam, but if you have a breaking load of 33kN/m (3.3 tons/m) as you mentioned earlier, your neighbor would probably need to significantly reinforce the beam because a KKR 180x180x6 in 355-steel only holds for 65% of that load.......
The weight of the steel beam decreasing from 300kg to 160kg is not only due to changing the beam type but also because you lowered your deflection requirement from 6mm to 15mm. Reinforcing the beam will likely increase the weight again and if you really want to benefit from the reinforcement, it's better to weld a flat steel to the top and bottom of the beam rather than adding an extra web.
Deflection is calculated based on the service load, so you don't need to account for all of your 15.6 tons in that case, but with a bathroom above with rolled waterproofing(?) I wouldn't want to exceed L/400 = 12mm in your case. If it's the bathroom's floor joists that are loading the steel beam, they have their own deflection too.
/The Engineer
The weight of the steel beam decreasing from 300kg to 160kg is not only due to changing the beam type but also because you lowered your deflection requirement from 6mm to 15mm. Reinforcing the beam will likely increase the weight again and if you really want to benefit from the reinforcement, it's better to weld a flat steel to the top and bottom of the beam rather than adding an extra web.
Deflection is calculated based on the service load, so you don't need to account for all of your 15.6 tons in that case, but with a bathroom above with rolled waterproofing(?) I wouldn't want to exceed L/400 = 12mm in your case. If it's the bathroom's floor joists that are loading the steel beam, they have their own deflection too.
/The Engineer
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I must have misunderstood something here.
Just now, a beam equivalent to an IPE 360 was needed, and now you're choosing a KKR 180x180x6, these two profiles don't even play in the same universe.
The KKR tube has a moment of inertia of 2037cm4 while an IPE has 16270cm4
That is, the KKR tube will bend 8 times more under the same load compared to the IPE beam.
Just now, a beam equivalent to an IPE 360 was needed, and now you're choosing a KKR 180x180x6, these two profiles don't even play in the same universe.
The KKR tube has a moment of inertia of 2037cm4 while an IPE has 16270cm4
That is, the KKR tube will bend 8 times more under the same load compared to the IPE beam.
the engineer: I will discuss with my neighbor about possibly welding on the top and bottom instead, if that's better. And of course, it will become heavier. I forgot to update the conditions. After some more precise measurements, the span will be 4.6m and not 5m. And yes, I lowered my requirements regarding deflection.
Gabbe: As you can see above, a few things have changed. I have new conditions and lowered my requirements, which has led me to where I am now.
Gabbe: As you can see above, a few things have changed. I have new conditions and lowered my requirements, which has led me to where I am now.
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A little update for those who are reading:
I had a post on 2010-04-21, 06:58. I must have had a brain lapse, or calculated very late at night because that calculation is not accurate at all.
You use what you have, so to speak:
On the top side of the vkr beam, an HEA120 will be welded, which gives a new TP seen from the underside at 132.9mm using Mr. Steiner (if I calculated correctly). Using that, a new moment of inertia is obtained, which is approximately 6200 cm4.
With an allowable deflection of L/300 = 15.3mm, it gives me an allowable force of 157 kN. Minus the weight of the roof itself, 37.5 kN, it gives me an allowable load of a total of 119 kN. If I subtract the maximum wind force that can arise, 18 kN, it becomes a total snow load of 101.5 kN, i.e., 10.1 tons.
I haven't yet calculated the buckling according to Euler, I was planning to use HEA120 as a column, or alternatively use a vkr pipe on one column since it will be visible in the house, but with that dimension, I find it hard to believe it could buckle, but that is the next thing to calculate
And I can add that now the beam becomes heavier again, but I have acquired a handy lift which solves all the problems. The high beam (294 mm) I can additionally fit in without "major problems"
I had a post on 2010-04-21, 06:58. I must have had a brain lapse, or calculated very late at night because that calculation is not accurate at all.
You use what you have, so to speak:
On the top side of the vkr beam, an HEA120 will be welded, which gives a new TP seen from the underside at 132.9mm using Mr. Steiner (if I calculated correctly). Using that, a new moment of inertia is obtained, which is approximately 6200 cm4.
With an allowable deflection of L/300 = 15.3mm, it gives me an allowable force of 157 kN. Minus the weight of the roof itself, 37.5 kN, it gives me an allowable load of a total of 119 kN. If I subtract the maximum wind force that can arise, 18 kN, it becomes a total snow load of 101.5 kN, i.e., 10.1 tons.
I haven't yet calculated the buckling according to Euler, I was planning to use HEA120 as a column, or alternatively use a vkr pipe on one column since it will be visible in the house, but with that dimension, I find it hard to believe it could buckle, but that is the next thing to calculate
And I can add that now the beam becomes heavier again, but I have acquired a handy lift which solves all the problems. The high beam (294 mm) I can additionally fit in without "major problems"
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Hello everyone who has read the thread. I haven't had time to follow up on the subject for a while.
I'm posting some pictures of how the result turned out. I reinforced the entire old foundation since it consisted of a very poor stone wall. For the pillars, I poured proper concrete foundations reinforced with rebar. As columns, I used an HEA120 and for the other a square beam 100. I then covered the square beam with plaster (see picture). The columns were bolted to the concrete. I received invaluable help from some neighbors when we lifted the beam in (after all, it weighed about 280kg). The beam was fastened to the columns using self-tapping bolts. The columns were also fastened to the timber beam using metal straps. Since the ceiling is low throughout the house, we tried to utilize all the ceiling height and made a sloped ceiling in the kitchen.
I'm posting some pictures of how the result turned out. I reinforced the entire old foundation since it consisted of a very poor stone wall. For the pillars, I poured proper concrete foundations reinforced with rebar. As columns, I used an HEA120 and for the other a square beam 100. I then covered the square beam with plaster (see picture). The columns were bolted to the concrete. I received invaluable help from some neighbors when we lifted the beam in (after all, it weighed about 280kg). The beam was fastened to the columns using self-tapping bolts. The columns were also fastened to the timber beam using metal straps. Since the ceiling is low throughout the house, we tried to utilize all the ceiling height and made a sloped ceiling in the kitchen.
For pictures see: http://www.byggahus.se/bloggar/dagodo/2555-stalbalk-tillbyggnad.html