Old Thread "Railing Posts Anchored with Non-Shrink Grout"
Old Thread "Railing Posts Anchored with Non-Shrink Grout"
(OP)
Has anyone become more enlightened regarding this thread? http://www.eng-tips.com/viewthread.cfm?qid=415064
I am struggling to prove that an existing railing embed connection works.
I am struggling to prove that an existing railing embed connection works.
One in the hand is worth two in the bush.






RE: Old Thread "Railing Posts Anchored with Non-Shrink Grout"
One in the hand is worth two in the bush.
RE: Old Thread "Railing Posts Anchored with Non-Shrink Grout"
Professional Engineer (ME, NH, MA) Structural Engineer (IL)
American Concrete Industries
https://www.facebook.com/AmericanConcrete/
RE: Old Thread "Railing Posts Anchored with Non-Shrink Grout"
If it is close by calculation, load test it. If not close....provide a fix. If aluminum, the fix is more difficult. If steel, not so much.
If you are proving the depth of fixity for an embed, check the attachment....
RE: Old Thread "Railing Posts Anchored with Non-Shrink Grout"
One in the hand is worth two in the bush.
RE: Old Thread "Railing Posts Anchored with Non-Shrink Grout"
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.
RE: Old Thread "Railing Posts Anchored with Non-Shrink Grout"
One in the hand is worth two in the bush.
RE: Old Thread "Railing Posts Anchored with Non-Shrink Grout"
50 lbs per linear foot, nominal 200 lbs per post if the posts are at their usual 4 foot interval.
But, where do you find the 200 lb test device? Surely not a bathroom scale turned sideways between the railing and a nearby wall.
RE: Old Thread "Railing Posts Anchored with Non-Shrink Grout"
RE: Old Thread "Railing Posts Anchored with Non-Shrink Grout"
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.
RE: Old Thread "Railing Posts Anchored with Non-Shrink Grout"
RE: Old Thread "Railing Posts Anchored with Non-Shrink Grout"
How much load do you apply and for what duration?
RE: Old Thread "Railing Posts Anchored with Non-Shrink Grout"
Adding to my comment previously of a low failure rate....that is because we are usually working on higher end construction I think. Hotels in Florida are required to be load tested; however, we do little of that because of our fee. There are some out there who will do this test for $200. We can't do that.
RE: Old Thread "Railing Posts Anchored with Non-Shrink Grout"
The embedment depth calculations based on concrete compressive strength are not clear to me. I include shear with the moment and calculate the elastic stress as V/A + M/S with A = diameter x embedment depth and S = diameter x (embedment depth)2 / 6.
RE: Old Thread "Railing Posts Anchored with Non-Shrink Grout"
In your horizontal load test setup you are using the column/wall on the LHS as a reaction to the ram/jack force, through the horizontal SHS?
Is that a 5-ton or 10-ton capacity ram/jack?
RE: Old Thread "Railing Posts Anchored with Non-Shrink Grout"
RE: Old Thread "Railing Posts Anchored with Non-Shrink Grout"
With a single-acting cylinder like the one you use (that uses a spring for the return) the calibration should consist of system-calibration (gauge, cylinder and pump) against a NIST-traceable load cell, not just a gauge calibration to a master gauge. At low levels of load the spring in a 10-ton ram provides considerable 'internal' resistance, resulting in less externally applied load/force, if using ram effective area x gauge pressure (which I don't recommend).
I usually use an external small-capacity calibrated load cell in these instances, for redundancy.
Sorry for the hijack, MacGruber22.
RE: Old Thread "Railing Posts Anchored with Non-Shrink Grout"
RE: Old Thread "Railing Posts Anchored with Non-Shrink Grout"
RE: Old Thread "Railing Posts Anchored with Non-Shrink Grout"
RE: Old Thread "Railing Posts Anchored with Non-Shrink Grout"
Let me re-phrase: When you design guardrail assembles, what factor of safety do you use?
RE: Old Thread "Railing Posts Anchored with Non-Shrink Grout"
RE: Old Thread "Railing Posts Anchored with Non-Shrink Grout"
KootK - the lug procedure is the way to go. Much more representative of the failure planes, I think. The only issue I do not like is that the bearing stress is not uniform as assumed in the lug breakout capacity (not to say that is was by rigging ACI anchoring equations!). I still worry about added tension from the moment about the btm edge of slab. The change in moment about that point is 18% when comparing a uniform bearing stress versus the "real" non-uniform, which in my case, gets me 5% under capacity. How have you rat
One in the hand is worth two in the bush.
RE: Old Thread "Railing Posts Anchored with Non-Shrink Grout"
I prefer ASD as well. This still does not make sense to me.
You are essentially testing the ultimate capacity of the assembly using 200 plf. If we design the system using wood, aluminum or steel, the factor of safety is built into the material allowables and ranges from 1.67 to 2.0 +/-, yet we still use the same 200 plf. load.
It seems you should either be testing the rail at 334 - 400 plf or we should be able to factor that load down when we design the system under ASD.
RE: Old Thread "Railing Posts Anchored with Non-Shrink Grout"
RE: Old Thread "Railing Posts Anchored with Non-Shrink Grout"
IBC 2012, ASTM and AC test requirments:
Keep in mind that "test load" sometimes refers to the requirement for the manufacturer product testing in a laboratory-type test, not necessarily a field-type load test.
When I did field-load testing to a plastic/vinyl handrail system about 20 years ago, the AHJ required we test to 2 x 200 lb.f. But the max test load in this instance was moot, the system failed at less than 200 lb.f!!!
RE: Old Thread "Railing Posts Anchored with Non-Shrink Grout"
There are some items for which load tests are carried to 125-200 percent of design. Pile load tests for instance. Guardrails are not one of those items. The ASTM Standard for testing guardrails does not require an additional safety factor nor does the building code or life safety code.
I agree with the points Shotzie noted.
RE: Old Thread "Railing Posts Anchored with Non-Shrink Grout"
Sometimes, to remain solutions focused, I think that one has to do something other than make all of their choices conservatively. I'll probably take a beating for saying so in present company but I really don't care about guardrails very much. I believe the code intent for guardrails really boils down to "stout". If I can parse out a defensible evaluation technique that gets me in the ballpark of "stout", I'm happy with that. Functionally, doing otherwise means that my client heads down the road and gives his business to a crappier engineer who will produce crappier engineering. Thus, my semi-crappy engineering makes the public safer than some other guy's fully-crappy engineering. And I can stay in business. I know, that probably sounds more than a little arrogant. I'm cool with that. This is the place for the unadulterated truth to be told after all.
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.
RE: Old Thread "Railing Posts Anchored with Non-Shrink Grout"
Also....Ingenuity...did you live in or near Ponte Vedra Beach at one time?
RE: Old Thread "Railing Posts Anchored with Non-Shrink Grout"
Especially in the world of glass guards. For every hour I have spent agonizing over stress distributions around holes in point supported glass guards, 3 other engineers in my city have rubber stamped a glass guard that would never pass a concept review. (for half the design fee too).
Sometimes, depending on the probability and consequence of failure of course, you are doing the world a favor by signing off on a guard that can resist 80% of its code required resistance, if everyone else in town is signing off on 50% or less.
Cue the debate on Locke vs Mill vs Kants theories of ethics
RE: Old Thread "Railing Posts Anchored with Non-Shrink Grout"
Interesting. I 'survived' 200+ mph typhoon back in 1997 when I lived on a tropical island in the Pacific - NOT many guardrails/handrail failures during that event compared to other structural failures, like 5" thick concrete roofs peeling/folding back from overhang corners of homes, prestressed concrete light/power poles snapped like toothpicks etc.
No, never visited/lived in any part of Florida...and sorry to admit that I had to google' where Ponte Vedra Beach is located.
RE: Old Thread "Railing Posts Anchored with Non-Shrink Grout"
Makes sense.
RE: Old Thread "Railing Posts Anchored with Non-Shrink Grout"
One in the hand is worth two in the bush.