Hobby carpenter
· Västmanland
· 210 posts
So I have an H-beam in the storage/workshop that rests on two vertical wooden beams. Its function is to support the joint of the rafters. It can be seen in this video at 7:22
I would like to use this beam to winch up a 5-600 kg heavy saw in the air while I work on the floor and I'm wondering how much load an H-beam like this can handle? I could find out more precise measurements if it's important to determine, but it's roughly 15 cm high.
I would like to use this beam to winch up a 5-600 kg heavy saw in the air while I work on the floor and I'm wondering how much load an H-beam like this can handle? I could find out more precise measurements if it's important to determine, but it's roughly 15 cm high.
Best answer
Hello
If it were the case that all beams of a certain type could withstand a specific load, structural engineers would be unnecessary. Unfortunately, it is not that simple; to determine what a beam can handle, we need input values. What is the current load on the beam, what do the supports look like, and what are the dimensions of the beam? In the video, it looks more like an Ipe beam rather than a Hea, but it's hard to tell from just a video.
We need to expose the beam and input values into each section to perform the calculation. First, determine which load case we are discussing, which requires the c/c distance of the rafters and how they relate to each other, as well as the total length of the beam. Then, to get a load per rafter, we need the dimensions of the rafter to calculate the load the beam receives from each rafter. We assume it is summer when you're planning to lift in the beam, so we don't include snow loads but will include wind loads.
Once we have these, we can calculate the deflection of the beam. Beams rarely break straight away; they bend down in the middle and buckle under critical loads. So, the acceptable deflection is what we can calculate.
Let's say this is 3 cm in the middle. To avoid making this an exhaustive explanation, we can assume that the load from each rafter (summer) is 700 kg (not sure if it's metal sheets or roof tiles).
After this is calculated, we proceed with your construction to ensure that the beam's supports can handle these values and what they can manage in additional load.
But to answer your question simply, if it hasn't collapsed under a lot of snow on the roof, you should be able to load the beam with an additional 600 kg without any problems. However, your supports don't look very confidence-inspiring, so I would replace them with new glulam posts of 115x115 or 90x90, depending on what fits.
If it were the case that all beams of a certain type could withstand a specific load, structural engineers would be unnecessary. Unfortunately, it is not that simple; to determine what a beam can handle, we need input values. What is the current load on the beam, what do the supports look like, and what are the dimensions of the beam? In the video, it looks more like an Ipe beam rather than a Hea, but it's hard to tell from just a video.
We need to expose the beam and input values into each section to perform the calculation. First, determine which load case we are discussing, which requires the c/c distance of the rafters and how they relate to each other, as well as the total length of the beam. Then, to get a load per rafter, we need the dimensions of the rafter to calculate the load the beam receives from each rafter. We assume it is summer when you're planning to lift in the beam, so we don't include snow loads but will include wind loads.
Once we have these, we can calculate the deflection of the beam. Beams rarely break straight away; they bend down in the middle and buckle under critical loads. So, the acceptable deflection is what we can calculate.
Let's say this is 3 cm in the middle. To avoid making this an exhaustive explanation, we can assume that the load from each rafter (summer) is 700 kg (not sure if it's metal sheets or roof tiles).
After this is calculated, we proceed with your construction to ensure that the beam's supports can handle these values and what they can manage in additional load.
But to answer your question simply, if it hasn't collapsed under a lot of snow on the roof, you should be able to load the beam with an additional 600 kg without any problems. However, your supports don't look very confidence-inspiring, so I would replace them with new glulam posts of 115x115 or 90x90, depending on what fits.
Hobby carpenter
· Västmanland
· 210 posts
Thanks for the quick response! My buddy also thought the supports were the weakest point, however, it's a bit harder to replace them when the entire structure is under load. But as you say, if the structure can withstand a layer of snow on the roof, it should hold for a saw, sounds logical. And that applies to both the beam and the supports in that case.
One idea might be to place a support under the beam near the saw, lift the saw, fix the floor locally, and then lower the saw and remove the support. Then fix the rest of the floor.
Alternatively, lift the saw with a couple of regular garage jacks and roll it away.
Alternatively, lift the saw with a couple of regular garage jacks and roll it away.
Hobby carpenter
· Västmanland
· 210 posts
My hope was to fix the entire floor at once and avoid any form of joint or similar, otherwise I could self-level one half, move the saw over, and self-level the other half as well.KnockOnWood said:
Hobby carpenter
· Västmanland
· 210 posts
Follow-up question on this - can I attach an additional beam to the existing structures? Basically, actually take two more 45x90 beams and screw them to the existing beams, but without them going down to the floor? The idea is to temporarily strengthen the two existing structures without interfering with my flooring (otherwise, there would be two 45x90 "holes" in the floor or two protruding beams on the wall).