Tie Loads?

A lot of them will already have a copy, do they not get a load of guidance notes when they do their training?
 
I do think the mortar joint one is misleading....if the conservation wont allow it do a buttress etc, if you cant do anything else why compromise or be forced to compromise the kn pull test rating which is deemed so crucial, you wouldnt get a fireman saying its ok to lock the fire exit because it made the room look untidy!

Somethings shouldnt be compromised yet nascs hypocrisy and bad teaching outed again !
 
I took it to mean they are obliged to let you know that it is possible to do it with the help of the right tie.
 
No they are evil swindling saville chaffeurs who you need to break away from before they poison you forever :D
 
We drilled B+P into brickwork , erected 8 lifts and a temporary roof on it all on single bolts i was always told that 2 fixings as close as a B+P will weaken the fixing. We had to use M12 expanding bolts with a 150 anchor , but like said a a stainless steel stud with epoxy resin takes a lot of beating , as for the shear loads if i remember right a B+P will hold something like 45KN
 
joebag said:
No they are evil swindling saville chaffeurs who you need to break away from before they poison you forever :D
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haha, what do you really think?:laugh:

---------- Post added at 04:36 PM ---------- Previous post was at 04:34 PM ----------
philliosmaximus said:
We drilled B+P into brickwork , erected 8 lifts and a temporary roof on it all on single bolts i was always told that 2 fixings as close as a B+P will weaken the fixing. We had to use M12 expanding bolts with a 150 anchor , but like said a a stainless steel stud with epoxy resin takes a lot of beating , as for the shear loads if i remember right a B+P will hold something like 45KN
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Sounds like the way to go Phil, testing them will be a nightmare though.
 
But the loads you require are in shear AOM so iam not sure what the pull test will need to be , this does look like a question for a designer
 
Yeah, he has went very quiet today for some reason hence the thread. I know you can theoretically test for shear but I thought that's why we use set and apollo bolts as the shear can be assumed in a known base material. We have done this before but never ever tested for shear and to be honest wouldn't know where to start.
 
Thanks for the tip Marra, does your gaffer not read your posts?:laugh:
 
aom said:
When using 2 hole B+P, what is the maximum load on the fitting if I have tested both fixings to 20kn? I seem to remember somewhere, someone mentioning 2 hole is not necessarily stronger than the single hole?
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Hi AOM, missed this post sorry,
From my early years the 2 holes in a B&P were only there to reduce weight, it was only when people started to use them for anchorage that the design changed to one hole.

The capacity of the B&P does not alter so I would assume it is the capacity of the ties in tension to which you refer.
2 anchors are not always better than one as the close proximity of the anchors in the substrate are where the restrictions lie. When extracting an anchor under force the tendency is to pull a cone shape from the material to which the anchor is fixed. Dependent upon the material to which you fix the cone may differ. Two such cone close together may overlap and as such reduce the surface area of resistance for the anchor thus making them less than twice as strong.
Hope this is of help
regards
Alan
 
Well I've just finished my advanced course this week and this was discussed in the classroom.

I was told that a B & P with 2 holes is classed as a heavy duty tie so should pull at 12.2kN where as a single hole B & P tie is standard duty so 6.1kN.

Think it was TG4:11 that covers this.

Hope this both helps and is correct :toung:
 
Spunkywads26 said:
Well I've just finished my advanced course this week and this was discussed in the classroom.

I was told that a B & P with 2 holes is classed as a heavy duty tie so should pull at 12.2kN where as a single hole B & P tie is standard duty so 6.1kN.

Think it was TG4:11 that covers this.

Hope this both helps and is correct :toung:
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I dont think it matters how many holes are in the b&p or o that fact what you rate it at on paper...a duty of a tie is designated by its pull test
So heavy duty will be 12+.if it fails then more have to be tested/drilled if the substructure or tie isnt sufficient then altetnitives should be sought - normal test is as required by desighn +5%
 
Spunkywads26 said:
Well I've just finished my advanced course this week and this was discussed in the classroom.

I was told that a B & P with 2 holes is classed as a heavy duty tie so should pull at 12.2kN where as a single hole B & P tie is standard duty so 6.1kN.

Think it was TG4:11 that covers this.

Hope this both helps and is correct :toung:
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Morning Spunky
The capacity of the material and anchor used is the issue here.
Example if you use this anchor on brickwork the holes are less than the minimum 150 apart. The 150 is required to prevent failure in the material to which you anchor.
Well installed ties seldom fail but the surrounding materials do.
TG4:11 makes reference to the use of twin anchors in B&P but I don't recall it indicating twice the load or in fact stating a load capacity I recall it makes reference to the two anchors sharing the load in shear but the tensile load is to be to the anchor manufacturers recommendation. It is in these recommendations that you will find the allowable loads and clearance required between them to attain given loads.
Hilti used to have a design guide (I guess they still do) I think All their anchors were tested in concrete as the ideal substrate and conclusions reached from the test results.
Contained within this design guide re the loads for single and multiple anchors.
Part of which detailed two anchors at given distances apart and the reduction of the anchor value dependent upon the distance. It’s been awhile but I seem to recall a 25% reduction for the HUS anchor and no results for M16 HKD.

As I say it all depends on the anchor and the substrate
 
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Hi Alan, thanks for that, I think the penny has finally dropped.:embarrest:

Am I right in saying then, that the 2 hole is not considered stronger in tensile but does help in shear as the load is shared?

The substrate is heavy stone and will hold any pull test no problem, the coning thing is something I have never heard of and could be a concern. In your opinion Alan, with a job of this nature, which is best, the single or double fixing?

We got a preliminary drawing back on Friday. There was no mention of the tie capacity but I'm guessing that will come with the final drawing. I was expecting a beam fixed to 2 droppers which would be bolted to the wall and spurred from there. I got a single tube fixed every 2 metres with the inside standard punched up and taking all the load. I suppose that's why we pay the designers, as I would have probably went into overkill on this job.

Congratulations on getting your advanced completed spunkywads, onwards and upwards.
 
aom said:
Hi Alan, thanks for that, I think the penny has finally dropped.:embarrest:

Am I right in saying then, that the 2 hole is not considered stronger in tensile but does help in shear as the load is shared?

The substrate is heavy stone and will hold any pull test no problem, the coning thing is something I have never heard of and could be a concern. In your opinion Alan, with a job of this nature, which is best, the single or double fixing?

We got a preliminary drawing back on Friday. There was no mention of the tie capacity but I'm guessing that will come with the final drawing. I was expecting a beam fixed to 2 droppers which would be bolted to the wall and spurred from there. I got a single tube fixed every 2 metres with the inside standard punched up and taking all the load. I suppose that's why we pay the designers, as I would have probably went into overkill on this job.

Congratulations on getting your advanced completed spunkywads, onwards and upwards.
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Never been a fan of the two hole fixing would sooner use two fittings if needed with a suitable gap between them.
Slightly more complex when it comes to the two bolts in shear as the offset of the load creates a rotation in the fitting putting the fixing into a combined tensile & Shear.

Scout around for a hilt book they will send you one if you ask there are details in there which will clear up my poor explanation on cone failure.
 
I kinda fell out with Hilti over the IW saga but could go cap in hand I suppose. The real reason I want to use the 2 hole Band and Plate is simply because it's all we have. As I said the stone is heavy and will pass a pull test but like you say some of the stones in fact more than likely all of them will have two fixings in the same stone.

Maybe I will reconsider my options.
 
As much as books and rules say aom, if its a dense stone with experience trust your instincts mate, or chisel a few out and sit beams on the wall itself, sometimes I think we forget what built this country in the first place ;)
 
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