×
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

Underground Utility Tunnel Expansion Joints

Underground Utility Tunnel Expansion Joints

Underground Utility Tunnel Expansion Joints

(OP)
I am working on a project that includes an underground CIP concrete tunnel connecting three different structures. The tunnel houses utility piping and will also be used by staff to cart laundry/food between buildings. The tunnel makes a "T" shape, with the stem of the T being approximately 200 feet, and the top of the T being approximately 370 feet. The question was raised as to whether or not we need to have expansion joints in the tunnel at intermediate locations between the three ends.

I have designed underground tunnels without intermediate expansion joints in the past, but not tunnels this long and with intersecting tunnel segments. However, I would not expect much thermal expansion with the tunnel being buried underground. Does anyone have any input on this issue? Are there any references that may be of use?

RE: Underground Utility Tunnel Expansion Joints

I do a lot of work with precast concrete culverts that are in that range of length. Typically each section is about 5 to 8 feet long with a shear-keyed cold joint. 2 strips of sealant are placed between each section and they are clamped together with carbon steel bolts grouted into bolt pockets. If moisture entering the structure must be avoided then they usually damp-proof the exterior. I've never considered thermal expansion or contraction beyond temp. and shrinkage rebar as the cold joints prevents that from becoming an issue.

Have you considered precast sections rather than CIP?

Maine EIT, Civil/Structural.

RE: Underground Utility Tunnel Expansion Joints

Once everything is backfilled, temperature changes mostly go away of course. During construction, however, you have to allow for all the short time shrinkage. You could consider pouring the tunnels with closure pour strips every so often (depending on your conditions).

Any moisture conditions to deal with? In my experience, it takes a true construction master to correctly install waterstop.

RE: Underground Utility Tunnel Expansion Joints

(OP)
Precast seems like it might be a good option. I imagine that could significantly cut down on construction time.

There are not any unusual moisture conditions to deal with on this project.

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