×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Are you an
Engineering professional?
Join Eng-Tips Forums!
• Talk With Other Members
• Be Notified Of Responses
• Keyword Search
Favorite Forums
• Automated Signatures
• Best Of All, It's Free!

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

5.11.4 Sliding Friction (Wind Force) & 5.11.2 Self-Anchored Tanks (Overturning Moment)

5.11.4 Sliding Friction (Wind Force) & 5.11.2 Self-Anchored Tanks (Overturning Moment)

(OP)
(A) For (5.11.4) Sliding Friction check, I put Fwind = (PWS * As-Vertical) + (PWR * Ar-Horizontal) where:
PWS (Design Wind Pressure on Shell) [see 5.2.1k.1)] = 0.89 kPa (V/190)^2.
As-Vertical (Vertical Projected Areas of Shell) = Shell Height * (D + 2 * tins-shell).
PWR (Design Wind Uplift Pressure on Roof) [see 5.2.1k (1 & 2))] = MIN(1.48 kPa (V/190)^2 , (1.6 * PF.4.1) ̶ Pi).
Ar-Horizontal (Horizontal Projected Areas of Roof) = π * (D/2)^2.
Am I correct or wrong?

(B) For (5.11.2) Self-Anchored Tanks, I found in existing calculation that the Mw (Overturning Moment about Shell-to-Bottom Joint from Horizontal + Vertical Wind Pressure) = MWR + MWS where
MWR (Moment Due to Wind Force on Roof) = (PWR * Ar-Horizontal * D/2).
MWS (Overturning Moment about Shell-to-Bottom Joint from Horizontal Wind Pressure) = (PWS * As-Vertical * (Shell Height / 2)).
In my mind this wrong as Overturning Moment (Mw ) is about Shell-to-Bottom Joint from Horizontal + Vertical Wind Pressure, so it should be concerned to SHELL ONLY (Roof should not be included) & therefore should be equal to MWS + (PWS * As-Horizontal * D/2) where (As-Horizontal) is Horizontal Projected Areas of Shell = π * (D/2)^2.
Am I correct or wrong?

Mohd Yaseen

RE: 5.11.4 Sliding Friction (Wind Force) & 5.11.2 Self-Anchored Tanks (Overturning Moment)

On the first item, I would not include the uplift on the roof in the calculated force.
On the second item, it should be PWR as the existing calculation shows.

RE: 5.11.4 Sliding Friction (Wind Force) & 5.11.2 Self-Anchored Tanks (Overturning Moment)

For (b), look at Figure 5.27 as a freebody diagram, in particular the point the Code is calculating the moment around. The wind uplift on the roof adds to the overturning moment from the shell wind pressure.

RE: 5.11.4 Sliding Friction (Wind Force) & 5.11.2 Self-Anchored Tanks (Overturning Moment)

(OP)
Dear JStephen/Geoff13;

For (5.11.4) Sliding Friction check, As I understood from you, the Maximum Allowable Sliding Friction shall be:
Fwind = (PWS * As-Vertical)
is it the same value as stated in F.8.2 (a) Uplift from Design Wind Velocity on Tank?

Mohd Yaseen

RE: 5.11.4 Sliding Friction (Wind Force) & 5.11.2 Self-Anchored Tanks (Overturning Moment)

In (a) I think you've figured out the forces trying to slide the tank, but you still need to figure out how much resistance the tank has against sliding.

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Resources

Low-Volume Rapid Injection Molding With 3D Printed Molds
Learn methods and guidelines for using stereolithography (SLA) 3D printed molds in the injection molding process to lower costs and lead time. Discover how this hybrid manufacturing process enables on-demand mold fabrication to quickly produce small batches of thermoplastic parts. Download Now
Examine how the principles of DfAM upend many of the long-standing rules around manufacturability - allowing engineers and designers to place a partâ€™s function at the center of their design considerations. Download Now
Taking Control of Engineering Documents
This ebook covers tips for creating and managing workflows, security best practices and protection of intellectual property, Cloud vs. on-premise software solutions, CAD file management, compliance, and more. Download Now

Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

• Talk To Other Members
• Notification Of Responses To Questions
• Favorite Forums One Click Access
• Keyword Search Of All Posts, And More...

Register now while it's still free!