Rectangular Tank Design

[jkate]

I'm needing to design a rectangular tank under hydrostatic pressure. I've been looking at procedures in "Design of Weldments" by Blogett, "PV Handbook", and a procedure I downloaded. The dimensions of my tank are 72"Hx72"Wx243"L made from A36 Carbon Steel.

Every procedure starts out by calculating the a/b ratio for a flat plate with 3 edges supported and 1 edge free (Roark Case 2d). In my case, a/b would be 72/243 = 0.296. Roarks Case 2d starts at an a/b ratio of 0.5, so my case is off the table. So how do I handle that? Do I cut the length in haf assuming there is a vertical stiffener there? Need some advise.

Thank you.

 

[MFJewell]

It's been a long time since I designed a rectangular tank, but I remember that I used stiffeners to get plate stresses to acceptable limits. I used Roark's for my calculations.

 

[mk3223]

Check the PV handbook which has the table of the a/b ratio (i.e. H/L ratio) from 0.25 to 4.

 

[MJCronin]

Yes, yes.... many stiffeners are required. There have been many discussions on this forum about the design of rectangular tanks.

Don't expect the tank to be cheap ..... By the fundamental nature of the design, they will be expensive and difficult to fabricate, inspect and coat.

Stiffeners (typically angles) will be required at all corners and at spans of about 3-4 feet along the sides. Many stiffeners means much welding and corrosion issues ....

The bottom will need to be continuously supported ....

What will the tank be used for ? Will it have an open top ? .... If so, you will need a top stiffening angle ....

Share with us your final solution


MJCronin
Sr. Process Engineer

 

[MJCronin]

http://www.eng-tips.com/viewthread.cfm?qid=206665

http://www.eng-tips.com/viewthread.cfm?qid=55086

MJCronin
Sr. Process Engineer