How to modelate a soil in SAP2000? 2

[sepultura]

I wan to modelate a building with the soil. Because the structure could have settlement. Is a soft soil.

Wich parameters must i put in SAP2000 to modelate la soil?

Thanks.

 

[DENSAL55]

you can modelate soil with spring stiffeness.

 

[Diquan]

Use SAFE is alot easier

=======================================
Diquan
diquan@yahoo.com

 

[sepultura]

which parameters of the soil i must know for use the spring stiffeness?
Could you explain me? I do not understand.

 

[DENSAL55]

It's same as when you calculate a beam on elastical supports, you represent soil by coefficient of reaction.
Soil - loose k=0.1-0.5 kg/cm3
- medium dense k=0.5-5
- dense k=5-10
- compact k=10-20
- hard k=20-100
you select joints at base then assign->point spring->kx ,ky,kz...etc.
i hope this help.

 

[sepultura]

Thanks DENSAL55 for your good response.

Is there any relation between coefficient of reaction (kg/cm3) of the soil and resistance soil support (kg/cm2)?

 

[DENSAL55]

Yes there is a relation between coeficient of reaction and resistance of soil p=-k*y
where y is the displacement
p is the pression on the soil
k is the coefficient of reaction.

 

[Diquan]

DENSAL55, i have a question, in SAP2000 v10 the closest thing is "assign->joint->springs->Spring Direction..., Spring Stifness... etc" and the help menu says that the units for that are force/length not force/cubic length or force/square length.

So exactly how that works?

=======================================
Diquan
diquan@yahoo.com

 

[DENSAL55]

As for loading
- when we have a slab i leave the value force/cubic lenght. p=-ky .
- when we have a beam on elastical support we must multiply the value by the width ( b ) of beam and thus we have force/square lenght. p=-ky/b .

 

[DENSAL55]

... and for point support we must multiply the value by the two plane dimenssion and we have force/lenght.

 

[sepultura]

DENSAL55.

Could you give me the equation to transform stress(kg/cm2) into Moment(kg-m) in flexural design.
I want understand the transformation, and do it manually to comprobate.
How could I do that convertion?

 

[DENSAL55]

See in "CSI Analysis Reference Manual Page 144 "

*Internal Force and Stress Output*

The Shell element internal forces (also called stress resultants) are the forces and moments that result from integrating the stresses over the element thickness.....etc