Contact US

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!

*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

Through Bolt Connection and Local Failure of Chimney?

Through Bolt Connection and Local Failure of Chimney?

Through Bolt Connection and Local Failure of Chimney?

Hi there,

I am working on a project where a client has attached a steel rod onto their chimney using mechanical anchors that are only embedded 1.5" and they wanted to check if this was adequate.

If the CMU block is hollow, the existing mechanical anchors used would be inadequate as HILTI seem to only allow chemical anchors for hollow masonry.

Although the chemical anchors pass my stress analysis in HILTI PROFIS, PROFIS does not verify if the chimney masonry will breakout, which I believe would govern. I have concerns about a local failure of the chimney itself. I’m conservatively assuming that the two existing connections impart a tension and compression load of 1.7kN respectively.

The chimney is made of 8” CMU block. The client says he is not sure if the chimney block was filled with concrete or if it was left hollow. The architectural drawings show that it was supposed to be filled. I would like to check both cases.

The chimney is not reinforced with steel, so I don’t expect the moment from the rod to transfer to the chimney foundation. It seems more realistic to me that if it does fail, there would be a local failure at the top (most likely in the skinny neck portion).

Chimney Dimensions :

Front Elevation :

Side Elevation :

Image is a bit blurry but height of rod is 13'.

To spread the pull out stress across the entire width of the chimney, I was thinking of creating a through bolt connection, where the bolt would go through the flue.

This is leading to a few questions:

1. I can’t find much reference or guidance material on through bolt connections for an application like this. Does anyone have any typical detailing best practice or guidance that they can share? Conceptually, I was thinking of this connection :

2. Is there a better way to reduce the stress on the chimney?

3. I can’t find much reference or guidance material on checking CMU chimneys for local failure from point loads (from anchors). How should I go about doing this? Is there any guidance material or worked examples for situations like this for both hollow CMU and filled?

Any help/guidance/advice would be greatly appreciated.

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


Low-Volume Rapid Injection Molding With 3D Printed Molds
Learn methods and guidelines for using stereolithography (SLA) 3D printed molds in the injection molding process to lower costs and lead time. Discover how this hybrid manufacturing process enables on-demand mold fabrication to quickly produce small batches of thermoplastic parts. Download Now
Design for Additive Manufacturing (DfAM)
Examine how the principles of DfAM upend many of the long-standing rules around manufacturability - allowing engineers and designers to place a part’s function at the center of their design considerations. Download Now
Taking Control of Engineering Documents
This ebook covers tips for creating and managing workflows, security best practices and protection of intellectual property, Cloud vs. on-premise software solutions, CAD file management, compliance, and more. 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