×
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

Concrete Cover

Concrete Cover

Concrete Cover

(OP)
Hi,

I have a situation where a concrete beam has been poured without the specified cover for reinforcing steel stirrups on one side. I have checked shear and torsion and one leg of the ties would be sufficient. Can one consider rendering the beam with a 3:1 sand:concrete mortar to provide the necessary cover?

Thanks

RE: Concrete Cover

It could be OK... small diametre main bars? Is bond an issue? and any problem with fire resistance?

Dik

RE: Concrete Cover

Render is quite porous, so I dont think it will have any benefit at all.

You should use a concrete repair mortar and bonding agent made specifically for patching spalled concrete. Google it.

RE: Concrete Cover

Could you simply paint it with intumescent paint?

RE: Concrete Cover

(OP)
JAE

I am more concerned about corrosion since the structure is close to the sea. Any comment about the render?

Thnx

RE: Concrete Cover

there are placement tolerances for cover and stuff like that.  chapter 4 or 5, i think.  depends on how much you have in the first place.

RE: Concrete Cover

If you are going to bother fixing it then use a proper product such as the ones mentioned. You generally need a bonding agent too so it sticks properly.

RE: Concrete Cover

what is the cover?

RE: Concrete Cover

(OP)
Hi

We have about 15mm right now

RE: Concrete Cover

I agree with csd's recommendation for a repair-type mortar with a corrosion inhibitor included in the material.

RE: Concrete Cover

what's the cover per plan?

RE: Concrete Cover

(OP)
swivel,

I don't know what you mean exactly but we have 15mm cover to one side of the stirrups in the worse case and have the required cover for the bottom and top bars.

thx

RE: Concrete Cover

what do the plans say the cover has to be?

RE: Concrete Cover

(OP)
Swivel

40mm

RE: Concrete Cover

if memory serves me correctly, i think ACI has tolerance....but i don't think anything that'll take as low as you have.  chapter 7 or something like that.

RE: Concrete Cover

ACI 318 Section 7.5.2.1 has cover tolerances...

(1) for effective depth d> 8 in (203 mm), tolerance is -1/2 in(13 mm)

(2) at beam soffits (which does not apply in this case), tolerance is -1/4 in (about 6 mm)

(3) cover tolerance must not be gretaer than -1/3 specified cover. in your case this will be 40 mm/3 = approx 13 mm

So I guess minimum acceptable cover will be 27 mm if you go by ACI 318 requirements...almost twice the actual cover.

Just curious...was there a concrete inspector before and during concrete placement?

Is the beam fire-rated or not?

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