Hilti Chemical Anchor HIT-HY 200 System
Hilti Chemical Anchor HIT-HY 200 System
(OP)
Who has used Hilti Chemical Anchor Bolts?
Any problem with it?
What is Hilti chemical made of?
I need to use it to reinforce the poor A307 (should have used A325 bolts) that was installed years ago..
Any problem with it?
What is Hilti chemical made of?
I need to use it to reinforce the poor A307 (should have used A325 bolts) that was installed years ago..






RE: Hilti Chemical Anchor HIT-HY 200 System
RE: Hilti Chemical Anchor HIT-HY 200 System
RE: Hilti Chemical Anchor HIT-HY 200 System
the 500 is fast drying
the 200 is slower drying
The hole must be cleaned out before applying, that's the major issue with this. The Hilti software should be available on their website, which may or may not need you to use the anchor fastening technical guide. All post installed anchors except for like one require you to use this bonding adhesive. Supposedly the bond is supposed to be stronger than concrete, however, construction generally makes the error of not cleaning out the holes after they are drilled.
RE: Hilti Chemical Anchor HIT-HY 200 System
The HIT-Z bolt requires no cleaning. You just inject the chemical gun and insert the bolts and good to go. It says:
"No hole cleaning required (above 5°C / 41°F) with HIT-HY 200" (see https://www.us.hilti.com/anchor-systems/anchoring-...)
I realized this morning the existing bolts was A307 (37.5 ksi) installed years ago. See picture at http://www.pbase.com/techroof/image/161552678
It's not A325. And the contractor was in hurry to put the metal plates. I stopped them and thinking about the poor A307. Then learnt the HILTI with 75.3 ksi can be used.
RE: Hilti Chemical Anchor HIT-HY 200 System
RE: Hilti Chemical Anchor HIT-HY 200 System
RE: Hilti Chemical Anchor HIT-HY 200 System
RE: Hilti Chemical Anchor HIT-HY 200 System
If the bond strength is what you need, I dont think it matters what the steel anchor bolt is, if its steel strength controlling, having a much stronger adhesive wont help. The connection is as strong as the weakest part, steel, adhesive, or concrete strength.
RE: Hilti Chemical Anchor HIT-HY 200 System
see:
(or http://www.pbase.com/image/161555922 if no image above)
The poor A307 is not just low strength but it is also near the edge. So liable to pryout failure. In the anchor near the edge.. what is the rule again? that it must not be less than 1.5 Hef.. so if the anchor bolt is 4 inches.. it must be at least 6 inches away from edge, right? Because now it's only 2.8 - 3 inches away from edge. Usually how near the edge do you put your anchors?
RE: Hilti Chemical Anchor HIT-HY 200 System
oh by the way.. does the Hilti chemical anchors need torques wrench? Because the HST mechanical anchors need one.. I guess chemical anchors don't need one.. correct?
RE: Hilti Chemical Anchor HIT-HY 200 System
RE: Hilti Chemical Anchor HIT-HY 200 System
RE: Hilti Chemical Anchor HIT-HY 200 System
As for a torque wrench, if a contractor cannot afford one, then I dont think I would want him on my job.
RE: Hilti Chemical Anchor HIT-HY 200 System
The designer proposed to add additional ones because he can't rely on the poor A307. What you mean the load will increase due to smaller moment arm? Can you give analogy in case of column?
RE: Hilti Chemical Anchor HIT-HY 200 System
Is the demand higher than the capacity of the A307? If not, use them and move on. If so, then get a new design from your engineer, install it and move on.
We are not here to do designs for you, nor teach engineering.
RE: Hilti Chemical Anchor HIT-HY 200 System
Designer uses smaller plate ignoring the contribution of the A307 by treating it as cut. But contractor made bigger plate enough to use it. And designer colleague didn't seem to mind. Smaller moment arm can attract more load? I'm thinking of analogy in foundation or column.. Larger moment arm is supposed to make it stronger.. unless you mean the smaller base plate is making the inside anchors attract more load.. hmm...
RE: Hilti Chemical Anchor HIT-HY 200 System
RE: Hilti Chemical Anchor HIT-HY 200 System
A higher tension load in the A307 bolt or the new bolt? Just this question and i'll visualize the rest. Thanks.
RE: Hilti Chemical Anchor HIT-HY 200 System
RE: Hilti Chemical Anchor HIT-HY 200 System
Consider columns.. the most edge bars would have more strain and stress than the intermediate bars via the strain diagram.. and if you don't use any intermediate bars.. the stress in the edge bars are the same. In the case of metal plates.. it also bends.. and the edge anchors would experience the same strain and stress.. what is the analogy in the case of columns.. just this so I can get your frame of reference. Thanks.
RE: Hilti Chemical Anchor HIT-HY 200 System
Maybe you need to post a new anchor layout so we can see how its laid out. Based on your detail i know would assume there are 8 anchor rods all at the same plane as the poor A307 rods.
RE: Hilti Chemical Anchor HIT-HY 200 System
This is the 0.5x0.5 mtr base plate that enclose all the 8 anchors (the 4 were not yet put.. maybe tomorrow if weather permits)
The blue dot is the A307 bolts (1 foot embediment) located about 3" from edge corner. The red dots are the additional expansion bolts to be put (the designer colleague said it's up to us.. more anchors better). Unfortunately. There is no stocks of the Hilti chemical bolts so have to use local GI expansion bolts. The light blue wide flange is the 1 foot support of the rafter you saw with the stiffener.
RE: Hilti Chemical Anchor HIT-HY 200 System
RE: Hilti Chemical Anchor HIT-HY 200 System
In ACI 318 Appendix D illustration (see above), i'm more concerned of shear loading than moment loading.. anchor so close to edge can result in pryout. This is even without any moment but just the structure swaying left to right. That's why the direction of the shear is horizontal.
RE: Hilti Chemical Anchor HIT-HY 200 System
Unless you have calculated the shear you are worried about resisting, there is no way to check the adequacy of your design. You need to know your design loads, before you can compare to capacity. It does not sound like you have quantified your loads (due to sway or other) and does not seem like you are able to compute said loads. That being said, what country are you in? Sounds like you are acting as a contractor and designer, which would be fine, if you were qualified to do so. by all of your posts, I am assuming you all are not qualified to be the contractor nor the designer.
RE: Hilti Chemical Anchor HIT-HY 200 System
First check if the chemical anchors or any hilti anchors are compatible to the seismic zones you are working on. This is very important, some anchors cannot be used in SDC D, E, F.
Note that Adhesive anchors have different strength reduction factors that more conservative (ACI 318-11)
I don't know what you mean to reinforce the A307, if this was cast in place you can use hairpin style reinforcement to gain strength for shear.
in your case, may be you can group anchors and figure out the combined capacity of anchor family. Any edge distance less than 1.5 x embed and any spacing less than 3 x embed depth requires strength reduction due to overlapping of the cones.
RE: Hilti Chemical Anchor HIT-HY 200 System
I'm just verifying the design of the designer because he made mistakes before. He for instance forgot to put stirrups in places that needed it before.. later he just designed carbon fiber retrofit because he forgot. So now I'm cautious and just want to double check if he would make another mistake.. the contractor will implement the plan tomorrow.. so have a few hours to do a halt of the project if I see another mistake in the design.
RE: Hilti Chemical Anchor HIT-HY 200 System
RE: Hilti Chemical Anchor HIT-HY 200 System
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RE: Hilti Chemical Anchor HIT-HY 200 System
For months and years. I've learnt how to derive the computations in beams, columns, foundations, even seismic. I generally avoided wide flange and base plates because I just wanted to focus on reinforced concrete. But this situation forces me to try to understand it.
Ive been trying to understand the principle or physics for it the past 2 hours.. I still can't understand.. if one add new sets of bolts inside the edge.. why does it decrease the moment arm and make the edge anchor seems more load. See the illustration above for some questions.
After understanding it. I'd no longer ask others. Lol. Thanks.
RE: Hilti Chemical Anchor HIT-HY 200 System
The example with the 4 bolts is more complicated, but essentially the outer ones are further away from the neutral axis and therefore see a larger share of the load. Imagine if your bolts were right in the middle spaced very close, you could imagine that this would not be very helpful to keep something (column) from tipping. Its the bolts applied closer to the edges of the base plate that will resist the overturning (moment).
RE: Hilti Chemical Anchor HIT-HY 200 System
Is there a counterpart of this principle in columns? What serves as the anchor there that depends on the moment arms? In columns. Putting the intermediate bars or not won't affect the forces in the edge bars because of the strain diagram.. and what is the equivalent in the concept of anchors and metal plates? also what is the moment arm in columns.. many thanks.
RE: Hilti Chemical Anchor HIT-HY 200 System
I understood the second part.. it's like the outermost bars in columns where they are the most stress. But according to jrisebo, if you suddenly add internal anchors.. it would change the outermost anchors contibution. Well.. in columns.. adding internal intermediate bars won't affect the values of the stress/strain at the outermost bars. Why would there be effect in metal plates? This is the part the I don't get.
Note jrisebo statement is "Well if you use the A307 and a new set of bolts, you are still decreasing your moment arm, so yes the A307 will see more load."
It's as if adding intermediate bars would suddenly change the outermost bars in columns. It doesn't. So what is jrisebo point out?
RE: Hilti Chemical Anchor HIT-HY 200 System
You have jumped to the column and the bars. Not the same thing.
If you have a set of anchors, and add more anchors towards the inside, the moment arm changes, and the loads change. Thats what I was getting at.
RE: Hilti Chemical Anchor HIT-HY 200 System
If you go from one set of bars to two set of bars, what happens to your 'd' distance for the group of bars. You increase the load, but with additional bars, you increase capacity.
Please prove me wrong.
RE: Hilti Chemical Anchor HIT-HY 200 System
i can understand it better using the concept of neutral axis. if you add more anchors inside. the outside anchors would still have same distance to neutral axis. yes or no? if same and you add more internal anchors. the outside anchors would still have same distance to neutral axis and have same load.. right? pls share references (even newtonian physics) so i can directly check them out.. tnx
RE: Hilti Chemical Anchor HIT-HY 200 System
jrisebo.. reflecting it today.. while it is true that shorter anchor distance would produce more force on the anchors.. the only way the edge anchor can be affected by adding or changing the middle anchors is if they are coupled.. so I think by adding middle anchors.. the stiff plate doesn't flex by moment but instead transfer the load to the edge anchor.. is this what you meant the load at edge increases when middle anchors were put?? if not.. please let me know why.. just this aspect.. thanks!
RE: Hilti Chemical Anchor HIT-HY 200 System
Going back to the original post, how do you know the A307 are not adequate for the load? Do you know the load?
You need to get a competent engineer involved, and based on your other post, that does not involve the company you are dealing with now. This is basic engineering, and if they cant get this right, the rest of the building is in question.
RE: Hilti Chemical Anchor HIT-HY 200 System
I went to the designer company this morning. The team leader said the A307 are adequate for the job. But they also give safety factors for construction error. Hence the 4 extra holes are just additional for extra margin.
So you are saying when the anchors are nearer to each other in a baseplate, there is a larger force in the anchors and at the same time the neutral axis rate of change would be faster.. hence there is more load in the tension side because the neutral axis moves a bit more... right?
The designer just says when the anchors are farther, there is less tension.. I asked him would there be greater load at the far edge.. he is silent.. he appeared not to consider what you were saying.
Anyway the 4 extra holes are just to strengthen the shear capacity (safety margin). Because the designer himself said moments are not large just enough to resist the wind load over the rafters. I discussed with him about pryout of the edge.. he seemed not to worry of it much.
Well. In our country. There is no course in structural engineering.. so ordinary folks can get the label of structural engineers by just 6 month short course and exam. That is why many don't even know the meaning of stress and strain diagram. This is exactly why I'm learning the theoretical foundation.. to analyze if they made possible mistakes.. like they had before. Because wherever I go.. the structural engineers don't put importance in knowldge of physics principle.. so they can't apply it in odd situation. Hence I need international assistance.
In a third world country. This is expected. So thank you so much for sharing even a bit. Don't worry I won't ask you on others things.. just this internal anchors affecting the load at the edge anchors.