×
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

ACI:What are the factor of load cases in analysis of piles
2

ACI:What are the factor of load cases in analysis of piles

ACI:What are the factor of load cases in analysis of piles

(OP)
Hi All,

I am working in project designed by ACI.

With members of the body structural part( slab, beam, column) I used combination with factored load (these combination are shown detailly in ACI).

to calculate the numbers of pile, I want to use allowable stress design (in which Force at top of pile compared with allowable capacity of pile), and use combination with unfactored loads. But I can not find provision showing detailly about these combination in ACI.

Could you kindly please give me a detail table about these above combination, for example:

1. f1D+f2L;
2. f3D+f4L+f5W;
3. f6D+f7L+f8E;
...
with f1=; f2 = ...

I am looking forward to hearing from you






 

 

RE: ACI:What are the factor of load cases in analysis of piles

D + L
D + 0.75L + 0.75W
0.6D + W
D + 0.75L + 0.75(0.7E)
0.6D + 0.7E

With these load combinations, a 1/3 increase in allowable capacity is not permitted.

DaveAtkins

RE: ACI:What are the factor of load cases in analysis of piles

(OP)
Thanks DaveAtkins!

Your counsel are highly appreciated.

One more question:
I found in IBC that "when having more than two or more transient load act simultaneously with the dead load,IBC 1605.3.1.1 permit a 25% transient load reduction-> have factor  = 0.75 in these cases. And I found the same in ACI standard;

But: About a 40% reduction of dead load in combination (0.6D+W, 0.6D+0.7E), I only found in IBC, did not in ACI;
Could you kindly show me:Where in ACI say about this reduction or where in ACI permit use IBC code (because in my project I have to use ACI code)

I look forward to hearing from you

RE: ACI:What are the factor of load cases in analysis of piles

OSE,

Chapter 8 (of ACI318-08), Section 8.2, defaults to ASCE 7. Chapter 2 of ASCE7,"Combinations of Loads" calls out the Basic Combinations in 2.3.2. IBC Section 1605.3 is similar to ASCE7.

I hope that this answers your question.

RE: ACI:What are the factor of load cases in analysis of piles

OSE,

In the two cases you asked about the 0.6D does not represent a 40% reduction in dead load.  Rather it is a 40% reduction in the stabilising effect of the dead load against the wind or earthquake load.  In other words, watch the signs.

RE: ACI:What are the factor of load cases in analysis of piles

ACI would not have a 0.6 factor anywhere, because concrete is designed using ultimate strength design, not allowable stress design.

DaveAtkins

RE: ACI:What are the factor of load cases in analysis of piles

(OP)
Dear All,

Thanks for your answers. They make me understand clearly about load combination.

I wish that we can discuss more in future.

With very best wishes,

OSE

 

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