×
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

THE FUTURE OF POST-INSTALLED ANCHORS – ASD vs SD

THE FUTURE OF POST-INSTALLED ANCHORS – ASD vs SD

THE FUTURE OF POST-INSTALLED ANCHORS – ASD vs SD

(OP)
The majority of engineering that I perform is done through ASD. Part or all of this practice may be changing in the future.

I notice that in some published, post-installed, Technical Guides or Design Manuals, spacing requirements are not available for Allowable Load charts that employ ASD. When I inquired of this with a post-installed anchor representative, over the phone, I was told, in that person’s opinion, that their company is leaning toward focusing more so on SD, Strength Design, rather that ASD, Allowable Stress Design. In fact, I was then directed to that company’s Post-Installed Anchor Software, which is exclusively designed by the employment of SD, Strength Design. ASD is not even a consideration for their, as well as their competitor's software.

In your opinions, if any of you have experienced this and/or have any insight or foresight regarding this, is this sway toward SD and away from ASD applicable only within the scope of post-installed anchors? Or, is this, perhaps, an indication of a likely future trend for engineering as a whole?

To help understand the current state, when commenting, please weigh in, if you will - Are you ASD or SD? (I realize the results of this poll will be solely influenced only by the number of participants.)

In your opinion, is there a benefit or detriment to ASD or SD, only regarding post-installed anchors. In general, I believe the ASD vs SD debate requires a separate post.

Thank you all!

RE: THE FUTURE OF POST-INSTALLED ANCHORS – ASD vs SD

From my perspective, it seems to be specifically a structural engineering trend, so the AISC and ACI are long headed that direction, but things like the ASME codes and tank standards are still allowable stress design, and I don't see any indication that that is changing. It's not a big issue, really, just have to make some adjustments where the two worlds interface with each other.

RE: THE FUTURE OF POST-INSTALLED ANCHORS – ASD vs SD

I just assume everything be ASD - at least until I retire

RE: THE FUTURE OF POST-INSTALLED ANCHORS – ASD vs SD

Outside the USA structural design is almost entirely based on the Limit State Method. This is neither "strength design" nor "allowable stress design", but a combination of the two, plus consideration of any other factors that may affect the performance of the structure.

Doug Jenkins
Interactive Design Services
http://newtonexcelbach.wordpress.com/

RE: THE FUTURE OF POST-INSTALLED ANCHORS – ASD vs SD

BSVBD,
Are you a Florida engineer? Are you accustomed to using anchor NOAs or just using manufacturers data that is provided in ASD?

I've had several meetings with technical representatives for Powers/Stanley B&D, Hilti and Simpson... All of which are concerned that east coast states and a couple in between are still doing ASD post installed anchors.

I've spoke to certain building officials about this and there are some who have absolutely no opinion either way. I think it has a lot to do with where you live or practice.

RE: THE FUTURE OF POST-INSTALLED ANCHORS – ASD vs SD

For better or worse, I use strength design for post-installed concrete anchors because the building code (IBC and ACI) only have strength design provisions. As to why this is the case, it is probably the same reason that ACI 318 only has strength design.

RE: THE FUTURE OF POST-INSTALLED ANCHORS – ASD vs SD

I think KootK could explain why for many circumstances, the concrete capacity method (from which current ACI anchorage is derived) is very good at predicting failure modes. And that is the major advantage of strength-based design. When you know the permutations of failure modes, the connections can be equally as reliable with greater efficiency.

"It is imperative Cunth doesn't get his hands on those codes."

RE: THE FUTURE OF POST-INSTALLED ANCHORS – ASD vs SD

I consider the whole ASD/SD/LRFD thing to be simply post processing.

Step 1) come up with an ultimate capacity somehow. Testing matching your situation exactly trumps all of course. In the absence of such glorious similitude, an evaluation method calibrated to testing is the way to go. Nowadays, the CCD method and its derivatives (app D) are, without question, the latest and greatest.

Step 2) use some statistically suitable scheme to convert ultimate capacity into a design value. This can be SD, LRFD, ASD, or Jupitorian stress transformation.

I expect that LRFD will eventually supplant ASD in all materials including wood, soil, and concrete anchorage. This will happen for the same reason that it's happened in concrete and steel design: it's inherently more rational. Load variability and capacity variability are independent stochastic mechanisms. You simply can't achieve uniform levels of structural reliability if those mechanisms aren't treated separately. And uniform structural reliability is always our goal even though we rarely express it explicitly in our day to day work.

I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.

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


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