Thread Capacity
Thread Capacity
(OP)
Hello Everyone,
I've searched previous threads and didn't come across the specific answer I was looking for.
I have a situation where we will be threading a ring bolt into the wall of a 1/4" thick hss. I have determined that the HSS itself can resist the load except for checking the threads for pull-out. The ring bolt also has the capacity I need but again am worried about the threads.
I know that if I could provide enough thread depth that the capacity would be strictly based on bolt capacity however that is not a feasible option. I was wondering what references people had here for determining the capacity of the threads.
The ring bolt will be loaded in pure tension only with a load of 5 kips. The HSS is a 6"x4"x1/4" with the threaded hole being drilled into the 6" face.
Any help on references would be great.
Thanks,
Jared
I've searched previous threads and didn't come across the specific answer I was looking for.
I have a situation where we will be threading a ring bolt into the wall of a 1/4" thick hss. I have determined that the HSS itself can resist the load except for checking the threads for pull-out. The ring bolt also has the capacity I need but again am worried about the threads.
I know that if I could provide enough thread depth that the capacity would be strictly based on bolt capacity however that is not a feasible option. I was wondering what references people had here for determining the capacity of the threads.
The ring bolt will be loaded in pure tension only with a load of 5 kips. The HSS is a 6"x4"x1/4" with the threaded hole being drilled into the 6" face.
Any help on references would be great.
Thanks,
Jared






RE: Thread Capacity
How about a hollo bolt?
RE: Thread Capacity
Mike McCann
MMC Engineering
RE: Thread Capacity
RE: Thread Capacity
You could also weld a nut on the face of the HSS, but from what I've read on this website, welding nuts to structural steel isn't acceptable practice.
RE: Thread Capacity
http://www.eng-tips.com/viewthread.cfm?qid=290559
http://www.eng-tips.com/viewthread.cfm?qid=35222
Alternatively if you're somewhere where you can still weld an attachment, just use a weld nut to give yourself a threaded attachment point. There are a million types out there and there is likely a configuration that will do whatever you want it to.
RE: Thread Capacity
I'm going to take a look at those threads as well as a hollo bolt (??)
Is it unreasonable to rationalize that since a nut provides 3/4" of thread depth and my HSS is 1/4" thick that I would have something slightly less than 1/3 of the tensile capacity of the bolt?
RE: Thread Capacity
I'm going to take a look at those threads as well as a hollo bolt (??)
Is it unreasonable to rationalize that since a nut provides 3/4" of thread depth and my HSS is 1/4" thick that I would have something slightly less than 1/3 of the tensile capacity of the bolt?
RE: Thread Capacity
And those Hollo bolts are quite interesting
RE: Thread Capacity
RE: Thread Capacity
Why can't you add some depth to the back of this plate if it's attached to a wall where no one will see it?
The relative depth argument needs to be treated with care and a healthy safety margin allowed. Either that or just get a few samples tensile tested. Much cheaper than the law suit you might end up in if it doesn't work.... Would also demonstrate to the architect that his idea doesn't work.
My motto: Learn something new every day
Also: There's usually a good reason why everyone does it that way
RE: Thread Capacity
RE: Thread Capacity
In the end we are not going to encorporate this detail (for a multitude of reasons but mainly the lack of redundancy in the system). The intent was to use them as travel restraint/fall restraint type tie-offs. We have convinced them to go with a continuous tie-off rail around the building perimeter with connections that are more robust and with significantly more redundancy if local failure were to occur.
From the get-go I was not comfortable with the design and noted my concerns however was told by a superior to try and make the eye-bolts work comfortably and in the end could not get a reasonable solution.
I much prefer the new framing option.