Allowable surface pressure
Allowable surface pressure
(OP)
Hi!
I neeh help guys.
The pressure formula p=F/A
Lets say that Im standing on a surface that has value of allowable pressure that it can stand of 10kN/m2
My weight is 100kg, wich is equal to 1kN.
Im standing on one foot.
Lets say that the area of my feet thats touching teh graound around 0.3m x 0.05m, wich gives a surface od 0,015m2.
The pressure that Im generating on a surface is 1kn/0,015m2=66,66kN/m2
Is it ok to say that the ground surface that Im standing on, will fail! Since 66,66kN/m2 > 10kN/m2
Lets imagine another situation where you have the same ground surface with allowable pressure of 10kN/m2.
Then I load it with a concrete box wich has dimensions 1,00 x 1,00 x 0,4m (height). Since the density of the concrete is around 25Kn/m3 it will generate a force of F=a x b x c x density wich equals= 1 x 1 x 0,4 x 25=10KN.
If I divide this force with the area that the box is touching the ground I will get an pressure value of 10kN/m2
We can say that the critical value is acchived a that the ground surface will probably fail.
The problem with this is that I cannot simpy visual this.
Me weight Vs. the concrete block
I generate greater pressure on a surface then the concrete block wich is 0,4m thick!
The ground surface will fail faster under my load and not under this concrete block!
?!)"?!
Can someone confirm this?
Thanx!
I neeh help guys.
The pressure formula p=F/A
Lets say that Im standing on a surface that has value of allowable pressure that it can stand of 10kN/m2
My weight is 100kg, wich is equal to 1kN.
Im standing on one foot.
Lets say that the area of my feet thats touching teh graound around 0.3m x 0.05m, wich gives a surface od 0,015m2.
The pressure that Im generating on a surface is 1kn/0,015m2=66,66kN/m2
Is it ok to say that the ground surface that Im standing on, will fail! Since 66,66kN/m2 > 10kN/m2
Lets imagine another situation where you have the same ground surface with allowable pressure of 10kN/m2.
Then I load it with a concrete box wich has dimensions 1,00 x 1,00 x 0,4m (height). Since the density of the concrete is around 25Kn/m3 it will generate a force of F=a x b x c x density wich equals= 1 x 1 x 0,4 x 25=10KN.
If I divide this force with the area that the box is touching the ground I will get an pressure value of 10kN/m2
We can say that the critical value is acchived a that the ground surface will probably fail.
The problem with this is that I cannot simpy visual this.
Me weight Vs. the concrete block
I generate greater pressure on a surface then the concrete block wich is 0,4m thick!
The ground surface will fail faster under my load and not under this concrete block!
?!)"?!
Can someone confirm this?
Thanx!





RE: Allowable surface pressure
If you think of walking on a soil surface and seeing your heel prints behind you, each of those represents a bearing capacity failure...small, but nonetheless a failure.
RE: Allowable surface pressure
The reason Im asking all this is because people are puting class that has load bearing capacity of 100kN/m2, for residental objects!
I found that to be reaaaaaaly to much. I talked to the selling stuff on this matter. Their answer was that styropor below 100kN/m2 is considered soft!?!
Must be somekind of selling propaganda! I mean 100kN/m2 give me a break! Maybe for garages where you ahve traffic load of cars, but for home use, no way!
RE: Allowable surface pressure
Most medium to high density EPS materials will have a compressive strength of around 100 to 175kN/m^2. Your consideration is on the low end of that range and should not be an issue, provided the material is fully supported.
RE: Allowable surface pressure
Im asking this couse you have EPS with compressive strenght od 10kN/m2 these days wich are use to damphen the walking noise thru structure.
RE: Allowable surface pressure
Don't confuse a "structural" application with a non-structural application.
RE: Allowable surface pressure
Thanx
RE: Allowable surface pressure
You have given almost no information so that we can help you with this. Please lay out your application and perhaps we can give you some suggestions, comments or advice that will be helpful. Otherwise, we are just trading random comments that resolve nothing.
RE: Allowable surface pressure
The thicknes of the EPS will be 4cm.
Then I will have a layer of concrete of 5cm over it and a layer of glazing (tiles) of 1 cm above all + load from house equipment, people load....
RE: Allowable surface pressure
The EPS you have questioned would be on the lower side of the range that I would specify.
RE: Allowable surface pressure