Tie Loads?

aom

aom

Well-known member
Joined
Feb 17, 2010
Messages
14,614
Reaction score
0
Location
Argyll
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?
 
Not over sure on the loadings al, but i suppose it would depend on what the scaffolds for. When we did the dropper at kings college hosp in london we had to fo pull tests of 12.5kn on 4 single holded b+p. Yet on the job im doing now were just box tieing round the steels and this job is netted.
It would also depend on what your base material is that your tieing into.
 
Its defo stronger aom, but alan reade needs to answer this as wishfull thinking has never worked on my pay packets either ;)
 
Thanks for the input boys. I'm sure someone mentioned that 2 hole can actually weaken a fitting due the close proximity to the holes, thought I would check.

The job we are doing is a fairly standard box or 3 sides are but one elevation is over very fragile tin roofs in poor condition and we have to strap everything to the wall with nothing touching the ground, probably about 30 odd meters. We have done a few like this in the past but couldn't quite remember what I did for testing the ties.
 
Id understand if it was into brick, concrete would be a different matter though surely, whats it drilled into ?
 
I don't think it matters too much what it's into being honest as long as the loads are reached but we as usual are going into heavy stonework. I will check my previous drawings but I'm sure 20kn was required for the job you see as my avatar. This one is slightly different though being just a whole elevation.
 
Again it will go on certain factors....ie base matetial, type ot tie used, height + leanght of scaffold, sheeted or netted and how many lifts boarded/ non boarded. And of course wind loading.
 
I will leave that to the designers Den, I was just wondering if I was testing them right. If they specify each tie assembly at 20kn, does that mean I only need to test each bolt to 15kn?
 
Thanks Rigger, I may just have to do that as I was looking back on some old drawings and it just says "suggested pull out test" which sounds like a cop out to me. I have been reading TG4 all morning but can't seem to find anything about the two hole set.

The old drawing I was looking at seemed to suggest a 15kn pull test for a 10kn load, so I assume the tie assembly should be 20kn.
 
My own personal take on the "one or two hole" debate is that one drilling of the base materiel, albeit larger, is less destructive than two smaller holes drilled in close proximity.

The next problem is using B+P you are restricted by the hole size as regards the bolt size used.Enlarge the hole in the B+P and you are changing the properties and basic design of this component. :wondering:

Happy days
 
Mmm, that's what I thought.

Mind you, I have no interest in using anything other than the standard M12, 100mm long and 12mm wide. The only thing I wondered about in that regard was would I need it slightly longer to allow for the rocker and band, but I see the manufacturer recommends a 60mm embedment depth so I should be fine with that as long as the pull tests come back Ok.

Feck it, think I will just wait to see what the designer has to say about it.:worried:
 
Must admit im of a different mind to two old battleaxes ;), even brick have a far and wide ranging density and porosity let alone concrete stone etc.....ive always felt that most brick even class b engineers would be better resined into rather than expanding something inside which would make em crack, two anchor points even though close together into a material such as concrete or a hard stone not sandstone would surely be stronger.....but resining into a hole and placing the tie in without expanding it is surely the strongest option?

Hilti dp a great two barrel system that sticks like sh1t to a blanket and goes off in minutes !
 
You may be right Joe, but I fecking doubt it, and less of the old.:laugh:;)

---------- Post added at 01:00 PM ---------- Previous post was at 12:58 PM ----------

All kidding aside, 2 fixings in one brick is certainly a no no. It could still work in stone or concrete though.
 
You dont drill your hole it the brick, you drill into the t section of mortor so as you install the tie its grips the three bricks surroding the tie bolt, something i was told by an old school scaff.
 
Worst thing to do mate, centre mass of the brick, mortar is extremely brittle also if you know the brick your using well you can even avoid the frogs (cavities) in them, now go and wash your mouth with fairy liquid ;)
 
Only passing on what i've been told joe.
Can i use morrisons own liquid as im not keen on fairy....lol lol
 
Read Riggers link, it's all in there. You can go into the mortar but only under certain conditions.
 
You must log in or register to reply here.
Top Bottom