Hey. Going to cast a slab between two concrete walls (there are also two walls extending towards the outer long wall, so it's actually four walls). The span is 2.5 meters and the length is 6.5 meters. Planning to place a mesh at the bottom and a 120 mm H-beam between the walls and a mesh on top. A total of about 22 cm of concrete. I only see advantages in casting beams, they should become incredibly rigid with concrete in them. Or is there too little concrete between the top and bottom of the beam? Here's the plan. Spacer at the bottom of 40 mm. Then reinforcement mesh 8 or thicker if needed. Then 6-7 beams and on top of this a mesh. Remaining above the mesh is about 4 cm of concrete. Best regards
Is the reason for the beams that you can't pour the slab directly on the walls? You can easily carry 2.5m with 220mm concrete.
If the top and/or bottom is going to be visible concrete, I would add a little extra reinforcement over the beams to minimize any cracks.
If the top and/or bottom is going to be visible concrete, I would add a little extra reinforcement over the beams to minimize any cracks.
I want to be sure that it will be super strong. Placing 7 H beams at 2.5 meters each feels like it should hold for a few cars and machines.
According to the standard, 250kg/m2 is calculated in parking garages ("normal" cars). If you skip the beams, a rough estimate would be a diameter of 8 with a center spacing of 200mm laid in the short tension direction. In reality, you have 4-sided support and if you are using a mesh as you mentioned, this is only advantageous. I would say you can skip the beams based on this. What kind of load-bearing walls do you have?
Concrete walls about 20 cm thick 😀. Got the number to the guy who was involved in designing the Ölandsbron, so I'll check with him too 😀.
Thank you so much for your help. Maybe overkill but really masculine with the beams I've already picked up. But if there's a risk of having too thin concrete over them, it's really unnecessary to cast them in. There will only be about 5 cm of concrete over the beams and about 4 cm over the mesh which was supposed to lie over the beams. Seems like it could be really strong with just "a little reinforcement."
Here's what I did..
Placed an 8mm mesh 50mm from the bottom (squares 150mm). On this mesh, 12mm rebar towards the outer wall about cc 400mm.
Spacers of about 60mm and another 8mm mesh with 12mm rebar on this about cc 500mm.
The meshes are overlapped and welded together. The meshes are welded at every loop that comes up from the walls.
The 12mm bars are hooked at the ends and welded together with the meshes.
I hope it's over-dimensioned now. Soon, 220mm of concrete will be added.
Placed an 8mm mesh 50mm from the bottom (squares 150mm). On this mesh, 12mm rebar towards the outer wall about cc 400mm.
Spacers of about 60mm and another 8mm mesh with 12mm rebar on this about cc 500mm.
The meshes are overlapped and welded together. The meshes are welded at every loop that comes up from the walls.
The 12mm bars are hooked at the ends and welded together with the meshes.
I hope it's over-dimensioned now. Soon, 220mm of concrete will be added.
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