The image describes a three-meter-long load-bearing wall that we want to completely remove to open up the downstairs. We are currently considering the necessity of a composite structure with steel beam, steel columns, and the short end pieces remaining of the decking in the load-bearing wall to also provide satisfactory static stiffness regarding dynamic loads, deflection, and vibration properties. This would improve the load distribution capacity while also transferring the load to the floor joists in the intermediate floor to the upstairs. The load-bearing wall, i.e., the supporting interior wall, currently has an existing opening which makes it difficult to measure how much the floor has sagged due to this after 20 years. It's difficult to know offhand what load will be applied to this steel beam, so I wonder if there are any standard values (read: generously estimated load) to use in the strength calculation to determine the size of the I-beam for the lintel and supports?
There are several things to consider with this type of renovation.
-What does it look like on the upper floor? Are the roof trusses also supported by the load-bearing wall you want to remove?
-Are there supports (that can handle the load) to place both pillars on?
-Is a building permit/construction notification required?
Regarding the load of the intermediate floor, the standard for residential buildings is usually 200kg/m2, and then you need to add some for the dead weight as well, maybe 50kg/m2.
Thank you for the welcome Gabbe1. The house consists of a basement, two floors, and an attic where the underpinning under the intended construction consists of double-walled brick in the basement that aligns with the ridge. The floor joists that will take up the load have cross-sectional dimensions of 70x230mm. The top of the foundation wall is flat and the sill rests approximately 100mm against the floor joists. The center-to-center spacing is about 600mm between the floor joists that rest against the sill where I have planned to distribute the load over two floor joists for each of the I-beam supports (4 in total) using steel plates bolted to the floor joists. According to your template values, the floor above constitutes a displacement of 8 tons. The trusses are of the framework model, which means that the outer walls alone take up the load from the roof's own weight as well as the added weight from snow, etc.
The whole resulted in an extensive calculation as a reshuffle will be made between openings and load-bearing walls on two of the floors, i.e., 5 load-bearing walls will be removed and steel beams installed, while 5 openings will be filled in.
The calculation resulted in construction timber 115x115mm for the side pillars and laminated beams 115x405mm (deformation 4mm) for the supporting beams, which should have provided a satisfactorily low utilization rate of under 60%. Now it's just a matter of converting this to the corresponding HEB beams in steel...
I wasn't quite sure how you are handling the loads from the columns down into the basement...
Is there a masonry wall directly underneath?
That's correct Mikael_L, under the entire load-bearing wall there is a double-brick wall. This is one of the four load-bearing walls that will be replaced with support beams.
For two of the other load-bearing walls, it's a much more complex load case since two load-bearing walls, one above the other, will be replaced by support beams.
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