Tomfh said:
Yes, but how can thru bolts be worse?
Has anybody said that the thru bolts would be worse? That said, I
can think of one way in which a thu-bolt might be worse, depending on the installation procedure. In predominantly shear loaded applications, you're relying on your anchor bearing against the substrate near the the loaded surface. An adhesive solution will generally create a nice condition there for relatively uniform bearing of the fastener against the substrate. Additionally, the adhesive will act to kind of hold the substrate together where the load is applied. If through bolts are installed with just the anchor sitting in the raw, drilled hole, these benefits would not accrue and I'd expect a decrease in performance owing to stress concentrations. That said, I've known engineers to thru-bolt but do so with the installation of some kind of adhesive/grout as well to help ameliorate stress concentrations.
Tomfh said:
If you’re prepared to accept a glue in-anchor, what reason is there to reject a thru bolt?
As mentioned above, many of us work in jurisdictions where we have to demonstrate to local building officials that things work. Where that is the case, it is much easier done with the adhesive anchor systems for which test data and established evaluation methods exist.
For probably the last decade at least, I've been asking the following on this forum regarding thru-bolts:
1) Is there relevant testing available to validate calculated capacity?
2) Is there an accepted design procedure for evaluating the capacity of thru bolts? All that I've ever seen is punching shear-ish checks on the back side and something to the tune of uniform bearing over six anchor diameters for shear. That's hardly rigorous and even that I've not ever seen in print anywhere. It's fun to design based on fundamental principles. However, much recent experience with concrete anchorage design and Northridge moment frame connections has taught us that we suck something fierce when it comes to doing accurate connection design based on first principles.
@Tomfh: if you have answers to either #1 or #2, it would pretty much make my week to hear them.
HELP! I'd like your help with a thread that I was forced to move to the business issues section where it will surely be seen by next to nobody that matters to me: