×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*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.

Students Click Here

Jobs

Modulus of Sub-Grade Reaction

Modulus of Sub-Grade Reaction

Modulus of Sub-Grade Reaction

(OP)
I was given a value of 150 KCF for my modulus of sub-grade reaction.

I've posted about this before, but could anyone give me some guidance?

How does this convert for a 20'x16' combined footing with 2'x2' panels?
Please let me know ASAP.

thanks.

RC
All that is necessary for the triumph of evil is that good men do nothing.
    Edmund Burke

 

RE: Modulus of Sub-Grade Reaction

I am getting that it should come out to 50K/in for each 2'x2' panel

RE: Modulus of Sub-Grade Reaction

(OP)
Is that just using 87 psi * (24"x24")? to get 50K/in?


Isn't there a formula to modify this based on the size of the footing?

RC
All that is necessary for the triumph of evil is that good men do nothing.
    Edmund Burke

 

RE: Modulus of Sub-Grade Reaction

I don't know where your 87psi came from, but what I did is this:
The 150 KCF is 150ksf per foot.  Multiply that by the panel siae of 4sq ft to get 600 K/ft, then divide by 12"per ft to get 50 K/in.

RE: Modulus of Sub-Grade Reaction

I don't know where your 87psi came from, but what I did is this:
The 150 KCF is 150ksf per foot.  Multiply that by the panel size of 4sq ft to get 600 K/ft, then divide by 12" per ft to get 50 K/in.

RE: Modulus of Sub-Grade Reaction

(OP)
87 psi is = 150 kcf ---> 150,000/12/144 = 86.81 psi

86.81 psi * 24"x24" = 50 kips/in

we just went about it using different starting points. Sorry for not making the 87psi clear. All examples I've seen use psi as the units so I wanted to be consistent with that.

RC
All that is necessary for the triumph of evil is that good men do nothing.
    Edmund Burke

 

RE: Modulus of Sub-Grade Reaction

(OP)
Isn't there a formula to reduce the modulus first K*1/B then K*(1+0.5(B/L))/1.5?

When does this apply?

RC
All that is necessary for the triumph of evil is that good men do nothing.
    Edmund Burke

 

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.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources