Replace 56x270 mm Glulam with HEB 120

[Aejohansson]

Last fall, I considered replacing the glulam beam between the hallway and the living room from a 56x270 mm glulam to a steel beam to reduce the construction height of the beam.

When I looked then, I had concluded that an HEB 120 beam could replace the glulam beam currently there. But now that I'm double-checking before ordering, I can't find where I got that information from. Have I been off track, or is it reasonable?

 

[scorp1on]

It is not possible to say outright; it depends on what is decisive, either in ultimate limit state or serviceability. Wood and steel have two completely different material properties, and thus the calculation also differs significantly. In this case, it is okay, as for example, a steel beam HEB120 can withstand a moment of 58 kNm. The corresponding glulam beam GL28c can withstand 12 kNm (assuming a 0.8 strength modification factor).

In terms of deformation, the product EI for steel is 1.815 x 10^6 Nm^2 and the corresponding glulam beam is 1 x 10^6 Nm^2, so the initial deformation should be okay.

 

[Aejohansson]

It cannot be stated outright; it depends on what is dimensioning; in limit state or service. Wood and steel have two completely different material properties, and therefore the calculation also differs significantly. But for example, a steel beam HEB120 can handle a moment of 58 kNm. A corresponding glulam beam GL28c can handle 12 kNm (assuming a 0.8 strength modification factor).

As you can see, an HEB120 handles significantly more in this case, probably less deflection as well.

I understand, a bit more data. 320 cm opening, 1-story villa snow zone 3-3.5, 340 cm from one outer wall, 370 cm from the other, 720 cm from outer wall to outer wall, 45-degree roof pitch with metal roofing. If anything can be made of that information.

 

[Aejohansson]

It cannot be said outright, it depends on what is determining; in fracture limit or serviceability. Wood and steel have two entirely different material properties and thus the calculation also differs significantly. In this case, it's okay as, for example, a steel beam HEB120 can handle a moment of 58 kNm. The corresponding glulam beam GL28c can handle 12kNm (assuming a strength modification factor of 0.8)

In terms of deformation, the product EI for steel is 1.815 x 10^6 Nm^2 and the corresponding glulam beam is 1 x 10^6 Nm^2, so the initial deformation should be fine.

Thanks for the help, I'm interpreting it as there shouldn't be any problems.

 

[scorp1on]

Yep