×
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

Definition of expansion joint

Definition of expansion joint

Definition of expansion joint

(OP)
I was arguing with my fellow engineers (all novices) about the definition and function of expansion joint.He was suggesting that the prime function of the expansion joint is it acts as a  temporary separator between two concrete surfaces during construction. To me he was implying that even if there is no filler but an initial gap say 25mm (one inch) is left behind it can still be called an expansion joint . Is this correct?

We both agree that expansion joint is provided to allow some movement (expansion of the structure) . I think this is quite obvious.

RE: Definition of expansion joint

Essentially, yes this is true. The purpose of the filler is to keep the expansion joint clean and working as deigned.

The problem with leaving out the compressible filler in the joint is that this gap could rapidly fill with non-compressible detritus.  This will then prevent the joint from moving and doing the work it was designed to do.

RE: Definition of expansion joint

Joints termed "expansion joints", in reality, act as contraction joints.  They are provided to account for drying-shrinkage in the concrete.  Rarely does a structure expand due to temperature differential more than it contracts due to drying-shrinkage.

RE: Definition of expansion joint

Here is my two cent contribution:

In general, an "expansion joint" is just that, it allows movement due to expansion and contraction between adjacent building elements.  The joint can be between the same material or different materials, in one structure or the interface between two different structures.  Since it is designed to move both ways, an expansion joint must be kept clean to allow the movement. If foreign material gets into the joint, it can prevent the intended movement, which can result in cracks appearing in unwanted areas.

For concrete, I generally see two types of joints; a "construction joint" and a "crack control joint".  A construction joint is the joint between two pours.  A crack control joint is install purposly, in specific locations to make the concrete structure crack at that point.

As an aside, concrete does expand thermally, just look at buckling of a highway pavement!  Also, there are special, expansive cements that expand during hydration, to counteract the effects of schrinkage.

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! Already a Member? Login


Resources

White Paper - A Guide to 3D Printing Materials
When it comes to using an FDM 3D printer effectively and efficiently, choosing the right material at the right time is essential. This 3D Printing Materials Guide will help give you and your team a basic understanding of some FDM 3D printing polymers and composites, their strengths and weaknesses, and when to use them. 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