Your inquiry has conflict with your attachments; as you are requesting to calculate strength for steel pipelines and your enclosed attachments are indicating PVC material. In this sense, referring to your att. "PVC Material"; kindly find the below answer for your inquiry:
Collapse Strength of PVC Pipe:
The following is the ASTM F 480 formula for determining the collapse strength of PVC pipe manufactured in accordance with said standards.
Pc=(2E/(1-u^2))/(1/((Do/t)[Do/t-1]^2)
Where: Pc = Collapse pressure of PVC pipe (psi)
E = Young's Modulus for PVC (4x105)
u = Poisson's Ratio (0.33)
Do = Outside diameter of pipe (inches)
t = Wall thickness (inches)
Another formula used to determine the collapse strength of PVC is shown below. This formula, is more conservative than the ASTM formula. However, since most PVC materials are made to minimum allowable wall thickness rather than nominal sizes, it may provide a more accurate estimate of actual collapse strength.
Pc=((2E)*.75)/(1-u^2)[Do/t-1]^3
Physical properties of PVC vary with temperature. The values obtained with these formulas are consistent with a temperature of 70°F. As the temperature rises, PVC working strength decreases by approximately 0.5 psi per degree Fahrenheit above 70°F. Obviously, much care must be taken during cementing operations or in other high temperature environments.
