guessing that your 95x95 posts handle between 1.5 to 2 tons each at 3m length, and many posts seem to be shorter = can handle more load. Is it really the posts that are bending? Feels more like you have too weak beams or too long a span on the beams. and if that's the case, cross bracing doesn't help much.
2*45*90 is usually considered stronger than 1*90*90 or have I gotten it mixed up now?
On the following page in Träguiden, there is a table showing which loads construction timber posts can handle with respect to dimensions, length, and strength class. The values apply in climate class 1-2, i.e., indoors or rain-protected. Outdoors (climate class 3) lower values apply.
https://www.traguiden.se/konstrukti...avor-av-konstruktionsvirke/?previousState=100
3-meter-long 95x95 posts of C 14 timber can then handle about 9 kN or approximately 900 kg in climate class 1-2.
https://www.traguiden.se/konstrukti...avor-av-konstruktionsvirke/?previousState=100
3-meter-long 95x95 posts of C 14 timber can then handle about 9 kN or approximately 900 kg in climate class 1-2.
That's not how you read the tables. Common construction wood, like 45x95, has a stiffer and a weaker direction. At a length of 3 meters, it can handle approximately 9 kN in the stiff direction. However, in the weak direction, it only handles 4.8 kN at a length of 2 meters, at 3 meters (which cannot be read from the tables) very little. A 95x95 handles about 9 kN in both directions at a length of 3 meters.
Try reading the table again. If buckling in the y-direction is eliminated, a 45x95 c14 can handle about 900kg in centric compressive force with a hinged connection at both ends of the post according to the table. A 95x95 can handle double that = 1800kg. (c30 can handle somewhere around 3000kg) I don't know which strength class of timber has been used. + I assume the connection is not hinged, so you should be able to add a few extra kilosJ justusandersson said:
Otherwise, you can check the table for columns in laminated timber, the load-bearing capacity is about 3500 kg for a 3m 90x90mm post.
For 45*90 to be better, it is of course assumed that they are screwed together; otherwise, it would just be the sum of two reglar. If they were loose, it would naturally be worse.
My intention with linking to Träguiden's table over buckling loads for structural timber was partly to show the significant importance of the strength class and how quickly the load-bearing capacity decreases with increased length of the post. I also thought it could be a simple way for someone not particularly knowledgeable in strength of materials to get an idea of a lower load limit. I now realize that it was not particularly pedagogically thought out, but rather contributed to increased confusion.
Träguiden's table is based on Euler's second buckling case [a column that is hinged at both the top and bottom] from 1744. The buckling load is directly proportional to the modulus of elasticity and the moment of inertia and inversely proportional to the square of the length. For a rectangular cross-section, the moment of inertia has different values in the rigid and weak directions. It is, of course, true that two beams can bear twice as much as one under comparable conditions. If you are going to extrapolate values from this table for posts with a square cross-section, you should preferably refer to the formula itself. If comparing with glulam (which is in another table in Träguiden), you should keep in mind that glulam has almost twice the modulus of elasticity as C 14 timber. The tables apply to climate class 1-2. For outdoor constructions (climate class 3), you can count on 60% of the capacity.
A deck that is as high as TS's on its edges should be dimensioned as a balcony. This implies a total useful load and dead weight of about 400 kg per square meter.
Träguiden's table is based on Euler's second buckling case [a column that is hinged at both the top and bottom] from 1744. The buckling load is directly proportional to the modulus of elasticity and the moment of inertia and inversely proportional to the square of the length. For a rectangular cross-section, the moment of inertia has different values in the rigid and weak directions. It is, of course, true that two beams can bear twice as much as one under comparable conditions. If you are going to extrapolate values from this table for posts with a square cross-section, you should preferably refer to the formula itself. If comparing with glulam (which is in another table in Träguiden), you should keep in mind that glulam has almost twice the modulus of elasticity as C 14 timber. The tables apply to climate class 1-2. For outdoor constructions (climate class 3), you can count on 60% of the capacity.
A deck that is as high as TS's on its edges should be dimensioned as a balcony. This implies a total useful load and dead weight of about 400 kg per square meter.
Good thinking and sure, one can try to understand. But it gets very deep hehe. If I try to summarize a bit then. To handle 400 kg/sqm on our deck/balcony. It feels like I really need more posts. And I'm thinking of placing a row in the middle of the deck. Then it will be about 2-2.5 m between the posts.