×
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.

# Foundation bearing stress calculation

## Foundation bearing stress calculation

(OP)
I am seeing Compress run two different types of calculations for foundation bearing stress (f_c). It is the same vessel and I'm running two separate operating loads (a separate calc for each load).

The heavier operating load (2,240,000 kg) causes Compress to run the equation for f_c as follows:

Foundation bearing stress (governing)

Ac = pi*(Do2 - Di2) / 4 - N*pi*db2 / 4
= p*(9182 - 8312) / 4 - 32*p*5.32 / 4
= 118,802.6 cm2

Ic = p*(Do4 - Di4) / 64
= p*(9184 - 8314) / 64
= 1.1453E+10 cm4

fc = N*Ab*Preload / Ac + (1 + 0.14*SDS)*W / Ac + M / 2*Do / Ic
= 32*14.2438*0 / 118,802.6 + (1 + 0.14*0.284)*3,184,834.87 / 118,802.6 + 10*5,778,801.9 / 2*9,180 / 1.1453E+10
= 51.034 kgf/cm2

As fc <= 100 kgf/cm2 the base plate width is satisfactory.

The lighter operating load (1,308,000 kg) is giving

Foundation bearing stress

fc = Cc / (((tc - ts) + n*ts)*(d / 2)*K2)
= 100*2,058,549.02 / (((435 - 1.66) + 7.8686*1.66)*(8,745 / 2)*1.8814)
= 56.057 kgf/cm2

As fc <= 100 kgf/cm2 the base plate width is satisfactory.

k = 1 / (1 + fs / (n*fc))
= 1 / (1 + 541.583 / (7.8686*56.057))
= 0.448868

Why does Compress choose which equation to use?

#### 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!