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Re:Split Rings

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Phil Taylen wrote:

. > I hope this is an easy one.  I'm designing a handrail at a
. > balcony with an occupancy less than 10.  I'm proposing 4x4
. > posts at 48" on center, each post is attached to one- 2x8
. > joist with 2-2 1/2" split rings.  Can someone with a lot of
. > experience with split rings consider this and let me know if
. > its a good design?


I would be very cautious using split rings and if I used them, I would use 
only 1/2 the tabulated allowable forces.

I have investigated truss failures where the split rings have sheared 
the wood (like a chisel) off the end of highly stressed diagonal tension 
members.  When I dismantled a truss that did not fail, the wood core inside 
the split ring came off with the split ring at one location.

The truss was well designed and complied with the codes existing when the 
truss was fabricated and when the truss failed.  Edge distances, end 
distances and center-to-center spacing were in complete compliance and, 
theoretically, the truss should not have failed, but it did.

If you do choose to use split rings, remember that the grooves have to be cut 
very precisely so that they will cause the split ring to open slightly when 
it is pressed into the hole.  It is not something that should be done in the 
field, particularly by carpenters inexperienced in split ring construction.

A. Roger Turk, P.E.(Structural)
Tucson, Arizona