Hello, everyone. This is Enta.
The other day, a craftsman I know asked me, “How much unevenness is acceptable on the back of a pressure plate?”
Wow—this is something that happens on set...The part that troubles me the mostRight? lol
Calculating the Area of a Compression Plate
The pressure plate is the anchor'sTransmitting Force to the GroundThat's why. If there isn't enough space,It sinks in lol
Hypothetical Conditions
- Design soil bearing capacity = 100 kN/m²
- Design Anchor Force = 200 kN
Required area = 200 kN ÷ 100 kN/m² = 2.0 m²
In other words,A bearing area of at least 2.0 m²That means it's necessary!
Since the actual usable area is 1.5 m × 1.5 m, it comes to 2.25 m² (the closest area).
What happens if there is unevenness?
On the back of the pressure plateThere is a gapIn such cases,Force is applied only to the areas in contactThat's how it works!
For example, if only half of the surface is in contact, the effective area is only 1.12 m². Yet the required area is 2.0 m²,That's not nearly enough!That's whysink inThat's right.
In reality, there is some indentation, but in the case of steel pressure plates, they may also deform (even though you can't see it).
The allowable unevenness is,Up to approximately 10% of the pressure-receiving plate area。For 90% and above, they must be in close contact.That's the point.
The difference between 2.25 m² and 2.0 m²
This means the allowable range is simply the difference between the actual load-bearing plate used and the required load-bearing area.
The basic rule is 100% contact!
Please understand that this is merely the acceptable range in the worst-case scenario.
Criteria for On-Site Decision-Making
- 5 mm or less: Tolerance Range
- 5 mm to 10 mm: Caution (a mat about 3 cm thick is recommended)
- 10 mm to 20 mm: Danger! (A mat at least 10 cm thick is recommended.)
- 20 mm or more: This is a total no-go, so you should already know that—make sure to take the necessary precautions!
Methods for Leveling Uneven Surfaces
① Zabuton Frame: That's the absolute basics.
② Adjustment Mat: Fill the gaps with a weather-resistant mat
Actually, this is the second time I've written this blog post—the first one just vanished...
It took me nearly two hours, and I ended up writing quite a long post, but...
It was actually much more substantial, but by the second time around, it ended up getting a bit thin (sob).
See you later.
