We will replace a load-bearing element with an HEA 180 beam standing on VKR 90x90 construction tubes. The plan is to cut and fine-tune the beams on site, so they will be delivered with some margin in the measurements. However, we are interested in having the beams cut at right angles and evenly, which will be crucial for the end result in the construction work. Among other things, flat iron will be welded to the ends of the 90x90 VKR profiles to spread the load onto the substrate, in this case, a concrete slab. My question is whether regular builders, whom I plan to hire for the job, can accomplish this on-site (angle grinder? gas cutter?), or can this only be done with good results using machines at the steel supplier?
Thank you in advance!
Andreas
Thank you in advance!
Andreas
Member
· Västerbottens län
· 18 059 posts
I gas cut such dimensions on HEA, if you're good at cutting, only a little grinding is needed.
VKR is borderline, cut or use an angle grinder.
What thickness should the flat bar be? It needs to be very thick if it's going to distribute the load over a longer distance. I question the need for load distribution; concrete is strong (compressive strength). Has an engineer calculated this? IF it has to be distributed, an angle bar is probably better (or a flat on its edge), and then the right angle isn't crucial.
VKR is borderline, cut or use an angle grinder.
What thickness should the flat bar be? It needs to be very thick if it's going to distribute the load over a longer distance. I question the need for load distribution; concrete is strong (compressive strength). Has an engineer calculated this? IF it has to be distributed, an angle bar is probably better (or a flat on its edge), and then the right angle isn't crucial.
The VKR profile will be placed directly on the concrete slab, and my plan is to weld a flat bar underneath the VKR profile to avoid the punching effect on the concrete slab, considering quite a substantial load will rest on top. I'm considering placing a couple of bolts through the flat bar into the concrete slab to secure it properly. In any case, I will remove the existing wooden beams on the floor where the VKR profile will stand because I'm quite convinced that the construction won't fare well with a bare VKR tube standing on a wooden beam...
I have construction drawings/calculations for everything, but I'm now pondering the details. I have received specifications for all dimensions, but there are a variety of ways to mount this.
I have construction drawings/calculations for everything, but I'm now pondering the details. I have received specifications for all dimensions, but there are a variety of ways to mount this.
Member
· Västerbottens län
· 18 059 posts
The concrete will hold. With what will you lift the beam to get the VKR tube in, a 1.5-tonne garage jack? 25-ton crank jack? That is the force that will be exerted on the VKR tube and on the concrete. What is the VKR tube estimated to withstand in terms of force?
Protte
Protte
There are a few different approaches, but the idea is to install the VKR pillars first and then place the beam on top (cut the VKR a few mm shorter than the height of the beam) and then wedge the beam against the inter-floor structure, essentially according to the attached drawing.
4 meters of HEA 180 weighs about 150 kg, which can, for example, be hoisted into position with a chain hoist temporarily mounted in the inter-floor structure.
4 meters of HEA 180 weighs about 150 kg, which can, for example, be hoisted into position with a chain hoist temporarily mounted in the inter-floor structure.
Member
· Västerbottens län
· 18 059 posts
In the drawing, it seems there's wood in the "post."
Shimming between the post and the beam requires steel inserts; the shim will only take on one side of the post.
If shimming is to be done, do it between the beam and the intermediate floor, then you can also fix any errors in the intermediate floor.
Nail guns are cool, but more moderate is to drill holes and use screws with nuts. Just make sure the A-dimension is correct.
I would still press the beam up against the floor until it creaks and then cut in the post.
Protte
Shimming between the post and the beam requires steel inserts; the shim will only take on one side of the post.
If shimming is to be done, do it between the beam and the intermediate floor, then you can also fix any errors in the intermediate floor.
Nail guns are cool, but more moderate is to drill holes and use screws with nuts. Just make sure the A-dimension is correct.
I would still press the beam up against the floor until it creaks and then cut in the post.
Protte
I would have cut with an angle grinder. Makes straight, clean cuts and no slag to grind. Otherwise, I agree with Protte regarding the installation. Cut in VKR when the beam is in place.
To my (our) house, we have KKR 90x90x5 supporting an HEB180 (4.40m long including supports) that acts as an intermediary floor beam, and on top of the HEB180 beam, a new KKR 90x90x5 continues up to a glulam beam at the roof ridge of the house. The glulam beam (also 4.4m) is 115x495 ("A"-trusses).
In other words, it is essentially the ridge beam (glulam) and the construction pipes that support the roof.
This is calculated by a truss company using TrussCon (some calculation/truss program).
My columns have a base of 10mm material and 120*180mm with 4 holes for fastening with anchor bolts to the slab, it is 120mm wide to be encompassed by the inner wall (13+12+95+12+13= 145mm, a little margin).
The concrete slab is 20 cm thick and 60x60cm with extra reinforcement, the base rests in the middle of this, the rest is a "normal" 10cm slab (villa).
The connection to the HEB180 beam is also made with a 10mm thick plate 120x180mm with the same hole pattern as against the foundation. Screwed into the beam, with M12 if I remember correctly. Here, there are really no torques as the rest of the building prevents such movements; the screws are meant to keep the "foot" of the column in place above and below the beam.
I ordered this from a metalworking company, and also ordered shims for this in 6mm and 2 mm 120x180mm with the same hole pattern, this I got in aluminum, but it doesn't matter much.
I ordered it pre-welded and 10mm "too short" to adjust for any unevenness in the slab or exterior wall which in my case was the reference height.
Just a few tips on how I did it, but my lifting was done with a crane truck during the erection of the frame, a bit simpler.
I see now that on your drawing there's a glulam post 115x115, but you'd rather have VKR?
In other words, it is essentially the ridge beam (glulam) and the construction pipes that support the roof.
This is calculated by a truss company using TrussCon (some calculation/truss program).
My columns have a base of 10mm material and 120*180mm with 4 holes for fastening with anchor bolts to the slab, it is 120mm wide to be encompassed by the inner wall (13+12+95+12+13= 145mm, a little margin).
The concrete slab is 20 cm thick and 60x60cm with extra reinforcement, the base rests in the middle of this, the rest is a "normal" 10cm slab (villa).
The connection to the HEB180 beam is also made with a 10mm thick plate 120x180mm with the same hole pattern as against the foundation. Screwed into the beam, with M12 if I remember correctly. Here, there are really no torques as the rest of the building prevents such movements; the screws are meant to keep the "foot" of the column in place above and below the beam.
I ordered this from a metalworking company, and also ordered shims for this in 6mm and 2 mm 120x180mm with the same hole pattern, this I got in aluminum, but it doesn't matter much.
I ordered it pre-welded and 10mm "too short" to adjust for any unevenness in the slab or exterior wall which in my case was the reference height.
Just a few tips on how I did it, but my lifting was done with a crane truck during the erection of the frame, a bit simpler.
I see now that on your drawing there's a glulam post 115x115, but you'd rather have VKR?
When I last assembled the beam, I first lifted the beam and secured it in place with flat iron strips. Then I attempted to lift using a 2.5t jack in the middle, but it didn’t work at all - too much load. However, it worked well to lift one end at a time - I then placed a temporary post at one end and lifted a few millimeters at the other. The permanent posts were then cut after taking measurements.
The lifting part can be a bit tricky; often you don't have much heavier equipment than a car jack to lift with, and you also have to consider what you have for support under the jack...
The lifting part can be a bit tricky; often you don't have much heavier equipment than a car jack to lift with, and you also have to consider what you have for support under the jack...
A variant to avoid lifting the steel beam with the entire weight of the overlying construction is to retain the wall that will be exchanged and demolish it only after the beam + post are in place. Admittedly, the beam will not end up exactly where the wall stood, but according to my constructor, there's no problem with the offset being a few decimeters offside... What do you think about this?
you should have a top plate 180*180*12 with four 18mm holes 35mm in from all sides, then the same hole pattern in the beam, preferably with a livavstyrning in the center. A base plate with 2 or four holes, make the length about 30 mm shorter than the height you want. Then drill holes in the concrete slab (same hole pattern as the base plate) preferably 18mm, then hilti HIT and M16 threaded rod, then mount the column with undersized nuts. Bolt the beam to the column. Then adjust to the correct height with the undersized nuts and grout between the concrete and the base plate. Just remember not to make the threaded rods too short; they can be cut with a grinder when everything is done.