Installed a glulam beam about two weeks ago, approximately 4.5m indoors (replaced a load-bearing interior wall). Supported on wooden posts at each end. Angle irons are screwed between the beam and ceiling joists. Have now discovered longitudinal cracks on one side of the beam today, approximately 50-60 cm long. Not through-going. Is this normal? Could it be related to the fastening? Is it dangerous or just normal tensions?
I think it sounds like you have exceeded the beam's shear capacity. Which is not OK. I can't imagine it has to do with the attachment. But whether there is a risk of failure or not, I can't say. How large is the deflection?
How confident are you that you have the correct dimension? Have you received calculations from a building engineer?
What is the dimension, and what does the load look like? That is, span, any load-bearing walls on top?
What is the dimension, and what does the load look like? That is, span, any load-bearing walls on top?
If there is a deflection of a few mm that is quite a lot since it is usually dimensioned so that the deflection y should not be greater than L/300. If you measure the deflection and give me the dimensions of the beam and the wood quality, I can calculate if you are overloading it.
My theory. In case of overload, the crack should occur in the middle, as the upper part of the beam is compressed while the lower part is extracted (is that the term?).hebbe said:
Torrspricka is another alternative.
staffan
Spontaneously, I think it sounds weak, but I am not a designer.
If we assume it's an intermediate floor, you probably currently have only a fraction of the load it should be designed for (200 kg/sqm). In practice, you only reach that load when you have the entire family visiting, but it should be designed for it anyway.
If we assume it's an intermediate floor, you probably currently have only a fraction of the load it should be designed for (200 kg/sqm). In practice, you only reach that load when you have the entire family visiting, but it should be designed for it anyway.
It's very hard to see how the beam would be overloaded without showing any deflection. Can't the dry season create dry cracks in glulam?
I will try to upload a picture of the crack shortly.
In my opinion, a beam loaded with a distributed load has the least stress in the middle of the beam.
I will try to upload a picture of the crack shortly.
In my opinion, a beam loaded with a distributed load has the least stress in the middle of the beam.
Yes, if I remember correctly from strength of materials (a long time ago), it was called the neutral line.
A horizontal crack in the beam’s neutral line does not at all mean exceeded load-bearing capacity. Shear cracks can appear anywhere along the beam's height, but the risk is least in the neutral layer where tensile forces at the bottom are replaced by compressive forces at the top (conversely over supports). Or rather: the risk is greatest where the change in length is greatest. And it should be within 1/4 of the height from the respective lower or upper edge to the respective edge.
Another and more likely explanation (since the beam does not bend downward and the crack is not through-going) is that it is a manufacturing defect due to a lack of bonding between the lamellas.
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Byggaren
Another and more likely explanation (since the beam does not bend downward and the crack is not through-going) is that it is a manufacturing defect due to a lack of bonding between the lamellas.
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Byggaren