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!

*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.

Jobs

Settlement Analysis (Which Load Combination?)

Settlement Analysis (Which Load Combination?)

(OP)
Hey,

Which load combination do you prefer for settlement analysis?

Unfactored G+Q or Unfactored G only where G is the dead load and Q is the live load. And do you have any reference for your answer?

RE: Settlement Analysis (Which Load Combination?)

I would use the dead load plus best estimate of actual live load. In storage structures like warehouses, grain elevators, and water tanks, the live load is very real and cannot be neglected.

No reference.

RE: Settlement Analysis (Which Load Combination?)

I would use DL + LL, both unfactored for service loads, since your are evaluating serviciability. If you want to set a range of estimated settlement, you can also calculate it with factored loads.

RE: Settlement Analysis (Which Load Combination?)

Pretty sure US AASHTO Service I is DL + LL unfactored for settlement. Some consideration of how the live load is determined and applied to a foundation system is needed though. There are some worst case scenarios that may overstate the typical live load condition for a settlement analysis. I think of multi-lane bridges with various loading conditions that can yield higher pressures. I think one needs to look for the highest average pressure over a effective footing width and not some odd structural combination that only exists for brief moments in time.

RE: Settlement Analysis (Which Load Combination?)

(OP)
Guys thank you. I also use G+Q. But I have to prove someone that this is true. Can you offer me any resource that proves your case?

Doctormo, yes, Service I state in AASHTO. Also they have a sentence that OVERALL STABILITY ANALYSIS SHOULD BE PERFORMED BASED ON THE SERVICE I. So this is the sentence I am looking for, only instead of overall settlements, it should say, SETTLEMENT CALCULATIONS. :)

RE: Settlement Analysis (Which Load Combination?)

Look in CalTrans design manual for foundations and retaining walls.

Settlement = Service State

One would never use factored loads for a service state calculation.

RE: Settlement Analysis (Which Load Combination?)

(OP)
Doctormo, that is the one I am looking for, but I couldn't see that on Caltrans Calofirnia Foundation Manual, either in 2015 or older versions. Can you specify exact location of that sentence?

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


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:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close