Yes, engineers 
Of course, I understand that one should not design directly against the yield strength. Even disregarding safety margins, the deflection often becomes unacceptably large.
But the steels you mention above are a remnant from the Stone Age (*irony*), and today most beams are manufactured in S355J2 (SS2172) or S355J2+M (2142). Regardless of whether you are a builder or an engineer, this steel has a yield strength of 355N/mm2.
Of course, I understand that one should not design directly against the yield strength. Even disregarding safety margins, the deflection often becomes unacceptably large.
But the steels you mention above are a remnant from the Stone Age (*irony*), and today most beams are manufactured in S355J2 (SS2172) or S355J2+M (2142). Regardless of whether you are a builder or an engineer, this steel has a yield strength of 355N/mm2.
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That shows how old I am!Gabbe1 said:Yep, engineer
Of course, I understand that you shouldn't dimension directly against the yield point.
Even if you disregard safety margins, the deflection often becomes unacceptably large.
But the steels you mention above are relics from the stone age (*irony*) and today most beams are made of S355J2 (SS2172) or S355J2+M (2142).
Regardless of whether you're a builder or an engineer, this steel has a yield strength of 355N/mm2.
I only had an old table nearby - it's been a long time since I was an active designer.
ok Gabbe1 and Anaitis,
do you agree?? is it ok with a certain safety margin with an IPE300?
and if so, follow-up question, standing columns at each end, should handle 55kN at a length of 3.8 meters...= dimension please
Anders
do you agree?? is it ok with a certain safety margin with an IPE300?
and if so, follow-up question, standing columns at each end, should handle 55kN at a length of 3.8 meters...= dimension please
Anders
With an IPE 300, you can sleep peacefully; it is more than twice as strong as an IPE 220.
However, the deflection at the center of the beam will be 42mm if you load it with your eight-ton distributed load, but if you can live with that when there is maximum wet snow on the roof, there is nothing to worry about. An IPE 300 made from 355 steel can actually handle over 18 tons of distributed load (freely supported with an 8.9m span) before it experiences permanent deformations.
Regarding the columns, 5 tons is not particularly difficult to support with a steel column, but you need to watch out for buckling, i.e., the column bending in the middle. If you're going to buy new material anyway, I would choose something like 100x100x4 VKR or KKR (square tubing) as it provides a nice solution often used specifically for columns.
Just make sure your concrete slab can support the load from these two columns.
However, the deflection at the center of the beam will be 42mm if you load it with your eight-ton distributed load, but if you can live with that when there is maximum wet snow on the roof, there is nothing to worry about. An IPE 300 made from 355 steel can actually handle over 18 tons of distributed load (freely supported with an 8.9m span) before it experiences permanent deformations.
Regarding the columns, 5 tons is not particularly difficult to support with a steel column, but you need to watch out for buckling, i.e., the column bending in the middle. If you're going to buy new material anyway, I would choose something like 100x100x4 VKR or KKR (square tubing) as it provides a nice solution often used specifically for columns.
Just make sure your concrete slab can support the load from these two columns.
Ok Gabbe1,
I was thinking 115x115x5 welded to a base plate 500x500x5 to distribute the load against the concrete, which is otherwise a reinforced cast slab of just over 15cm.
That should comfortably fall within the safety margin...?
Anders
I was thinking 115x115x5 welded to a base plate 500x500x5 to distribute the load against the concrete, which is otherwise a reinforced cast slab of just over 15cm.
That should comfortably fall within the safety margin...?
Anders
That pillar becomes very sturdy and good.
But the base plate is pointless to make 0.5x0.5m if you're only going to use 5mm sheet metal, it will be too weak to support anything on the edges anyway.
Try to get hold of 10-15mm sheet metal instead, and I instinctively believe that a plate of 300x300mm is sufficient.
But the base plate is pointless to make 0.5x0.5m if you're only going to use 5mm sheet metal, it will be too weak to support anything on the edges anyway.
Try to get hold of 10-15mm sheet metal instead, and I instinctively believe that a plate of 300x300mm is sufficient.