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

Related Articles


Strengthening RC beam with externally bonded plates.

Strengthening RC beam with externally bonded plates.

Strengthening RC beam with externally bonded plates.

My friends

I am looking for good design references/guides on the strengthening of RC beam (for flexure and shear) using externally bonded plates. Theory and practice if possible. While FRP is well-covered, this one seems not to be.

Thanks for your time.


RE: Strengthening RC beam with externally bonded plates.

FRP seems to be the preferred material for externally bonded strengthening; however, the principles would be the same for any externally bonded reinforcement, only the approach to providing shear bond between the concrete and the external reinforcement varies. Steel used as external strengthening is typically anchored into the concrete, rather than attempting to bond it to the surface. Most often, external steel strengthening takes the form of anchored end blocks connected with high-strength threaded bars, steel prestressing strand, or carbon fiber strands as post-tensioning, since it is typically more effective than unstressed reinforcement.

RE: Strengthening RC beam with externally bonded plates.

Fire rating would be a consideration.


RE: Strengthening RC beam with externally bonded plates.

When adding reinforcing externally that is of similar capacity to you internal reinforcement, you need to look closely at the strains in each layer allowing for the strain in the concrete at the time of the addition of the external reinforcement.

You normally will not be able to use the full capacity of the added external reinforcement as its strain will be limited to below the yield strain due to compatibility considerations.

This is not such a problem with CF as you are never using the full capacity of the CF due to bond considerations. And with external; PT, the steel is stressed to 60-70% of breaking before being bonded, so again normally not so much of a problem.

RE: Strengthening RC beam with externally bonded plates.

Now a somewhat dated publication by ACI is "SP-165: Repair and Strengthening of Concrete Members with Adhesive Bonded Plates ".

It is a collection of conference papers from 1992, printed in 1996. No longer in hardcopy print, but individual papers are downloadable here: Link.

Free if you are an ACI member.

RE: Strengthening RC beam with externally bonded plates.

There is also a publication T55 by The Concrete Society (UK): Design guidance for strengthening concrete structures using fibre composite materials.

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!


White Paper: Industrial Control Basics: Contactors
A contactor is an electrical device used for switching an electrical circuit on or off. Considered to be a special type of relay, contactors are used in applications with higher current carrying capacity, while relays are used for lower current applications. Download Now
Research Report: State of IoT Adoption in Product Development 2019
This research report, based on a survey of 234 product development professionals, examines the current state of Internet of Things (IoT) adoption by product design teams, its perceived importance, and what features and capabilities teams consider important when making decision about adding IoT functionality to their products. Download Now
Research Report: Augmented Reality for Maintenance, Repair and Overhaul (MRO)
The term Industry 4.0 denotes a cluster of technologies that’s poised to fundamentally reshape manufacturing and bring about a new industrial revolution. These include 3D printing (AM), the Industrial Internet of Things (IIoT), artificial intelligence (AI) and mixed reality technologies, more commonly known as virtual reality (VR) and augmented reality (AR). Download Now

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