Casting a lid for a drinking water well

[Värmlandsmicke]

It will hold up fine. We cast a well cover 25 years ago with a diameter of about a meter and as I remember it, we placed about 4 straight and crisscrossed rebar in the middle of the slab (7 cm thick.) Still holds up nicely today. We engraved our names and the year... might last a few hundred years, who knows.

That's the biggest reason to cast. I've promised the kids to let them make handprints. And now that I've put in several days of work and will transport the cover 250 kilometers to get it in place, I don't want it to sit at the bottom for at least 100 years

 

[witten]

The reinforcement should be in the lower half of the height because that's where the concrete is subjected to tensile stress when the lid is lifted. In the middle, it doesn't serve much purpose unless it's crack reinforcement - so bottom reinforcement about 25 mm from the bottom of the mold should be good.

It's not quite that bad with reinforcement in the middle. What happens is that the tension zone moves to the middle and the compression zone becomes 35 mm.

One thing you should consider is placing the bars along the short side at the bottom and those along the long side at the top. End the bars 50 mm from the concrete edge.

 

[Värmlandsmicke]

It's not quite so bad with the reinforcement in the middle. What happens is that the tension zone moves to the middle and the compression zone becomes 35 mm.

One thing you should think about is to place the bars along the short side underneath and those along the long side on top. End the bars 50 mm from the concrete edge.

I'm starting to realize more and more that I should stick to my profession as an electrician. Electric fencing would have been a good solution

 

[witten]

I'm starting to realize more and more that I should stick to my profession as an electrician. Electric fences would have been a good solution

Yes, but the longevity depends on the reinforcement not being too shallow anywhere.

It's good that there are electricians too, so that we have lights and bubbles in the hot tub.

 

[Värmlandsmicke]

Sure, but the lifespan depends on the reinforcement not being too shallow anywhere.

It's good that there are electricians too so that we have light and bubbles in the jacuzzi

That's exactly where I am now. With too shallow reinforcement. Otherwise, it's reinforced like hell. Will it last longer if I galvanize the mesh? I'll check the price tomorrow. Otherwise, I have to rethink the whole concept.
-"Redoing is not doing..."

 

[Ingenjören]

Place a layer of reinforcement dia 8mm centrally in the lid in both directions, it will certainly hold, and you avoid the greater risk of the reinforcement rusting in 20 years.

 

[Värmlandsmicke]

Lay a layer of reinforcement dia 8mm centrally in the lid in both directions, it will definitely hold, and you'll avoid the greater risk of the reinforcement rusting in 20 years.

It seems more and more like that's the solution, unfortunately...

 

[mexitegel]

It's not quite as bad with the reinforcement in the middle. What happens is that the tension zone moves to the middle and the compression zone becomes 35 mm.

One thing you should consider is to place the bars along the short side at the bottom and those along the long side at the top. End the bars 50 mm from the concrete edge.

Sounds strange, the largest movements should reasonably be closest to the surface at the top/bottom.

 

[Ingenjören]

The strength (for tensile stresses at the bottom) is better with the reinforcement at the bottom, but physically it works the same with the reinforcement in the middle, it just creates a smaller compression zone and internal lever arm, and thereby lower strength, but in this case with small spans and moments, it will be more than sufficient.

 

[Värmlandsmicke]

The strength (for tensile stress at the bottom edge) is better with the reinforcement at the very bottom, but physically it works the same with the reinforcement in the middle; it just results in a smaller compression zone and internal lever arm and thus lower strength, but in this case with small spans and moments, it will be more than enough.

I'm afraid the lid will not lie flat with the surface. I actually wanted to cast it in place, but the well is awkwardly located. A span of 700mm is nothing, but if the lid rests on three corners, you have no idea where the load will be..?

 

[witten]

Sounds strange, the largest movements should reasonably be closest to the surface at the top/bottom.

What is beneath the reinforcement is called the cracked zone and it is, theoretically, statically inactive.

 

[Värmlandsmicke]

What is beneath the reinforcement is called the cracked zone and it is, theoretically, statically inactive.

That sounds reasonable.