×
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

Precast Plank - Structural Topping vs Non-Structural Topping
3

Precast Plank - Structural Topping vs Non-Structural Topping

Precast Plank - Structural Topping vs Non-Structural Topping

(OP)
What is the difference between Structural Topping vs Non-Structural Topping in terms of specifications required or performance requirements?

I understand that structural topping is considered to act compositely with the planks but what is done differently when a structural topping is used vs a non-structural topping. Assuming they are both concrete?


 

EIT

RE: Precast Plank - Structural Topping vs Non-Structural Topping

By using the Ctrl-F trick or search of incidences in PCI 6th handbook one can find the main incidences soon such:

Do not relay in FRP for mechanical reinforcement in toppigs.
Be aware that the tables for topping use fc=3 ksi in the topping.
Other superior strengths can be used, as seen in the examples.
When no topping ties must be provided to ensure integrity and diaphragm action.
That ACI uses to exclude non-topped structures when diaphragm action is considered (except equivalent performance is met by other design).
Since ACI 318-02 one should repeat the search in 318-08 for the incidences.

Other than that and for composite action all is to follow science of construction, considering what available at the moment. Non composite toppings should normally considered only as weights.

RE: Precast Plank - Structural Topping vs Non-Structural Topping

I think Ishvaag hit it right on the head of the nail. Nothing to add here.
 

RE: Precast Plank - Structural Topping vs Non-Structural Topping

(OP)
Thanks Ishvaaag.

I will look through the PCI handbook as I beleive we have a copy (should have thought of this first).

As far as practicality goes - Is specifying a 2" structural topping with WWF reasonable? It seems like in this area, Illinois, most toppings are nonstructural so I want to make sure that I convey this to the contractor.

EIT

RE: Precast Plank - Structural Topping vs Non-Structural Topping

The issue is more or less addressed here.

http://www.eng-tips.com/viewthread.cfm?qid=182794

I think most here (Spain) wouldn't blink on using a thin wire mesh to reinforce such topping, bout of course everyone has its advocates.

RE: Precast Plank - Structural Topping vs Non-Structural Topping

Nonstructural topping is usually gyp-crete or some other self-leveling compound. You'll need to make sure you evaluate compressive strength of the self-leveling topping so you get a good product with its intended use, eg is it a wearing surface also, what thicknesses can it be applied in. With nonstructural, you'll need to check the stress in the keyways between the plank in order to develop a diaphragm, limiting it to 80 psi factored.  

RE: Precast Plank - Structural Topping vs Non-Structural Topping

This is also available for free, if you haven't seen it yet.

PCI Hollow Core Slab Design Manual

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