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philliosmaximus

philliosmaximus

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I have been asked to pull test band and plates to 9.4KN on a design ,
When I pull tested them we could only achive 7KN.
The bands and plates are not being used in shear only in a pull out capacity .

I rang the designer and was told to use the 2 hole bands and plates if I couldn't achive the 9.4KN.

My question is the band and plate still only as strong as the 7KN test ?

What I have done is used an Apollo 14mm nylon tie beside the band and plate which I pull tested to 9KN ,
Surley this is stronger then a 2 hole band and plate ?
 
Run it by the designer or just do as he says because if something happens he will say you didn't follow his design even though what you do maybe better
 
What Derry says.
But what is giving way on the band & plate?
If you put two ties close together and/or close to the edge of the base material, they can interfere with each other and you can get less holding power with 2 fixings than you would expect - it certainly won't be twice what one will hold.
 
Band & Plates are rated at 23.0 kN for the straight pull through the coupler i.e. no slip. It would depend on what is failing at 7.0 kN as to whether the 2 hole and 2 anchor method would help the capacity.
 
Are you testing the B&P or are you testing the anchor?

The B&P will be much stronger than your requirements as previously mentioned.

Two anchors in close proximity are not always a good thing, you are more likely to create substrate issues (failure in whatever the anchor is fixed to as opposed to the anchor itself).

The 9.4 required test may be the old 6.25kN value x 1.5 fos (1.25 is your standard bolt fixing test requirement) which you would test prior to the B&P being installed onto the anchor.

It is however safe to assume the Engineer has his reasons for the number and test required.

Take a look at TG4:11
 
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If I was you, I ring the designer and let them know the outcome of the pull test. Depending on the purpose of the tie they may just revise the drawing and calcs to show Apollo rather than Excalibur/Thunderbolts/whatever or if the B&P is a crucial element, advise you on how to proceed. Either way, contact your designer so your arse is covered.
 
Alan Reade said:
Are you testing the B&P or are you testing the anchor?

The B&P will be much stronger than your requirements as previously mentioned.

Two anchors in close proximity are not always a good thing, you are more likely to create substrate issues (failure in whatever the anchor is fixed to as opposed to the anchor itself).

The 9.4 required test may be the old 6.25kN value x 1.5 fos (1.25 is your standard bolt fixing test requirement) which you would test prior to the B&P being installed onto the anchor.

It is however safe to assume the Engineer has his reasons for the number and test required.

Take a look at TG4:11
Click to expand...

Hi Alan ,

Sorry it's the actual anchor I have pulled tested to 7KN on a single hole band and plate ,

Iam just wondering why an extra anchor in a 2 whole band and plate with get me a higher load capacity ,
If both anchors pull to 7KN then surley the whole tie will only be as strong 7KN ?

I will give the designer a call ;)

---------- Post added at 11:30 AM ---------- Previous post was at 11:24 AM ----------
Alan Reade said:
Are you testing the B&P or are you testing the anchor?

The B&P will be much stronger than your requirements as previously mentioned.

Two anchors in close proximity are not always a good thing, you are more likely to create substrate issues (failure in whatever the anchor is fixed to as opposed to the anchor itself).

The 9.4 required test may be the old 6.25kN value x 1.5 fos (1.25 is your standard bolt fixing test requirement) which you would test prior to the B&P being installed onto the anchor.

It is however safe to assume the Engineer has his reasons for the number and test required.

Take a look at TG4:11
Click to expand...

Hi Alan ,

Sorry it's the actual anchor I have pulled tested to 7KN on a single hole band and plate ,

Iam just wondering why an extra anchor in a 2 whole band and plate with get me a higher load capacity ,
If both anchors pull to 7KN then surley the whole tie will only be as strong 7KN ?

I will give the designer a call ;)
 
philliosmaximus said:
Hi Alan ,

Sorry it's the actual anchor I have pulled tested to 7KN on a single hole band and plate ,

Iam just wondering why an extra anchor in a 2 whole band and plate with get me a higher load capacity ,
If both anchors pull to 7KN then surley the whole tie will only be as strong 7KN ?

I will give the designer a call ;)
Click to expand...

It sounds like they're suggesting the load then becomes split between the 2 bolts, leaving a tie load of 3.13 kN per bolt making the new test load on a single bolt of 3.13*1.5 = 4.70 kN. But as stated above, it depends on the material you're fixing into. Other things can become a factor such as hole spacing, edge distances etc. It wouldn't do you any harm to check the data sheets from the bolt manufacturer to see what the recommended loads are for the different materials they can be fixed in to.
 
philliosmaximus said:
Hi Alan ,

Sorry it's the actual anchor I have pulled tested to 7KN on a single hole band and plate ,

Iam just wondering why an extra anchor in a 2 whole band and plate with get me a higher load capacity ,
If both anchors pull to 7KN then surley the whole tie will only be as strong 7KN ?

I will give the designer a call ;)

---------- Post added at 11:30 AM ---------- Previous post was at 11:24 AM ----------



Hi Alan ,

Sorry it's the actual anchor I have pulled tested to 7KN on a single hole band and plate ,

Iam just wondering why an extra anchor in a 2 whole band and plate with get me a higher load capacity ,
If both anchors pull to 7KN then surley the whole tie will only be as strong 7KN ?

I will give the designer a call ;)
Click to expand...


No Problem,
the load may well be split into the two bolts and as stated each bolt may take half the load.

That said the element to which you are fixed may not agree with this, testing the anchors is not the same as testing the suitability of the element to which you fix.

That said that is all we are required to do then it becomes a "foundation problem"

when you use your Hilti type tester it only tests the anchor in the local sense ie: it tries to pull the anchor from the place element into which it is inserted.
the tester does not however; test the element itself in the global sense ie:
a 2m x 2m brick panel with a bolt in the middle, when you test the bolt your bridge is only a short distance either side of the bolt thus tests the bolt only.

If you did away with the bridge and then applied the load to the bolt without supporting off the panel would you pull the panel out? which would then be testing the element itself?
F**k it sounded simpler in my head!!
 
Trying to justifying a global load from a local test is never simple. It's a pain when those questions arise and no client in their right mind is going to let you test the building fabric in this way.
 
We didn't start a job two year ago as we had to drill into concrete panels. When we went to test the ties we did achieve the pull out we needed at local area but couldn't be sure if the panel was strong enough and we had no means of testing it. The construction firm and their engineers didn't seem to understand what I was saying because the tests were showing strong enough. One engineer finally got it but me and him were chased and another firm started the scaffold
 
derryscaff said:
We didn't start a job two year ago as we had to drill into concrete panels. When we went to test the ties we did achieve the pull out we needed at local area but couldn't be sure if the panel was strong enough and we had no means of testing it. The construction firm and their engineers didn't seem to understand what I was saying because the tests were showing strong enough. One engineer finally got it but me and him were chased and another firm started the scaffold
Click to expand...

my point in a nut shell
 
I called the designer and he is happy with what I have done ,
But Iam still a bit confused as to how 2 holes can share a load as I thought if the strongest
One went it would take the second one with it ( it kind of reminds me of a girl I once knew :laugh::laugh:)
 
I think the theory is that for pull out loading it would be evenly distributed between the two and two is better than one. However, as Alan has stated it depends on material that your drilling into and two holes close together can cause weakness
 
I think that's true plus, a designer doing the calculations for 2 hole could put all the shear load through 1 fixing and the pull through the other.
 
What ever happen to the days when you grabbed the ring tie with 2 hands ,
Put your feet against the wall and pulled as hard as you could for a pull test
:laugh::laugh:
 
Hi phil - what are you actuslly testing m8 is it the fixed b&p ur pullin on or is it just the bolt prior to fixing the b&p to it - what type of anchors & bolts are you using as i got good results with M10 excaliber bolts sat in the b&p wiv a moon washer....could it just be your drilling into bad brickwork if so u may have to concider chem ties such as hiltihit
 
southernpoofter said:
Hi phil - what are you actuslly testing m8 is it the fixed b&p ur pullin on or is it just the bolt prior to fixing the b&p to it - what type of anchors & bolts are you using as i got good results with M10 excaliber bolts sat in the b&p wiv a moon washer....could it just be your drilling into bad brickwork if so u may have to concider chem ties such as hiltihit
Click to expand...

How's it going Sp ,
It's just the bolt I was testing in soft brickwork,
We are using M12 shield ancours which are 150 long and have a 20mm hole,
The whole tie when complete would have a half moon washer .
I still can't get a decent pull on an Excalibur bolt in soft brick work ,
So I don't use them mate .
 
philliosmaximus said:
How's it going Sp ,
It's just the bolt I was testing in soft brickwork,
We are using M12 shield ancours which are 150 long and have a 20mm hole,
The whole tie when complete would have a half moon washer .
I still can't get a decent pull on an Excalibur bolt in soft brick work ,
So I don't use them mate .
Click to expand...

It not your anchor that is failing its the structure. You either need a different anchor or build it on a different building!!

Seriously if you give Hilti a call they can recommend and test suitable anchors to overcome your specific difficulties.
 
Alan beat me to it m8....sounds like ur probs not with the tie itself but the substucture try hilti hit chem ties - although you'll prob need a slightly different anchor insert talk to ur local hilti rep he'll steer you towards the tight product
 
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