×
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

Column reinforcement ratio at splices
2

Column reinforcement ratio at splices

Column reinforcement ratio at splices

(OP)
Let's say you have a RC column with 4% steel.  At splice locations, you will have twice as many bars in the cross section.  Will these bars count toward your ρg, giving you 8% steel at splice locations?  Is this addressed in any code or text that you know of?

I don't want to try (incorrectly imo) take the bars into account for strength; I want to check steel limits.  If you have 4.5% steel for instance, then at a splice, you would have 9%, exceeding your 8% limit.

RE: Column reinforcement ratio at splices

You count the main bars and you don't count the double bars at the splice.

RE: Column reinforcement ratio at splices

i believe that they will count for the ratio, but not for the strength.  

RE: Column reinforcement ratio at splices

2
The maximum ratio of 8% is the maximum at any cut through the cross section - so at lap splices where they are doubled up you can have a max 8% (so max 4% for strength elsewhere in the column).  If you use mechanical splices however you could run 8% throughout the entire column length.

RE: Column reinforcement ratio at splices

As a code basis for my statement see R10.9.1 of ACI-02:  "...the percentage of reinforcement in columns should usually not exceed 4 percent if the column bars are required to be spliced."

RE: Column reinforcement ratio at splices

WillisV has it.  The maximum reinforcing at any cross-section is 8% and if you have lapped splices, the maximum is 4% assuming the reinf above is the same as that below.  This is one of the few areas of code (ACI and CSA) that hasn't changed for 40 years.  If the axial load is high enough or the load is in straight compression, the column size can be minimized using mechanical splices.

Dik

RE: Column reinforcement ratio at splices

I stand corrected.

Thanks for the info.

RE: Column reinforcement ratio at splices

(OP)
What a great help you all are.

I mentioned this to a more senior engineer at work who didn't take my word for it about counting the lap splices with the reinforcement ratio but I couldn't back it up at the time, so I needed a reality check.  

RE: Column reinforcement ratio at splices

If any a bind with high reinforcing ratios you can require that the splices be staggered at intervals so as not to exceed 8%

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