tail joist connection 1

[jim57]

I am analyzing a deck that has a double 2 x 8" girder that supports floor joist with a tail joist connection, three nails through the girder into the side of the joist. Need a code reference that says this is or is not acceptable. I need to prove why it is not acceptable and if and when it ever was

 

[dhengr]

Jim:
We can’t see it from here. And, what’s a tail joist connection?
Show a sketch of the detail with dimensions and all the loads, so that we can understand what you’re looking at.

 

[MiketheEngineer]

Go to NDS for nail values - about 100 lbs per nail

 

[jim57]

The double girder is supported by posts. Therefore the floor joists are supported by the three nails only

 

[structSU10]

So you are nailing into the end grain of the joist for connection? That is not a good detail. Why not use a simpson face mounted hanger or something?

 

[woodman88]

Not sure what your building code is based on, per the 2009 IBC section 2304.4 “Floor and roof framing. The framing of wood-joisted floors and roofs shall be in accordance with the provisions specified in Section 2308 unless a specific design is furnished.”
So if you have a design by an engineer (or building designer, where allowed by code) the design controls the bearing requirements. As long as the design, such as a Simpson hanger or framing clip, does meet the code and engineering standards requirements.
The 2009 IBC Section 2308 states a minimum required size of 1.5" (or a 1x4 ribbon and joist nailed to studs) in Section 2308.8.1 for floor joists. Headers 1.5" requirement is in Section 2308.9.5.2. The 1.5" minimum bearing is also noted as require in many other sections of 2308.
The same applies to the IRC.

As for your detail, it would depends on what forces need to be transfered. But I would prefer to use a hanger and see no real reason not to. So the question is, can you find an engineer (or are willing able and will yourself), not me, to design and seal it. The values for end nails would be per the NDS under the IBC code.

Garth Dreger PE - AZ Phoenix area
As EOR's we should take the responsibility to design our structures to support the components we allow in our design per that industry standards.

 

[jim57]

Sorry for the confusion. i am working backwards. This connection is on an existing deck and it failed under the weight of a 22" deep swimming pool. I realize that the weight of the water may have caused the final straw in the deck demise, but would like to find a reference stating that this connection is improper. I have found the 1967 Building Code that states if the floor joist is greater than 6', it must have a steel strap or hanger. The code further states that joists shall on 1.5 inches or have a1" let in ribbon.

Thanks

 

[woodman88]

Again I do not know which building code you are looking it. The 1.5” bearing or 1x ribbon etc. requirements are to my knowledge have been applied to a “Conventional Construction” or “Conventional Light-framed” provisions of the codes. The codes UBC (back to my copy of the 1976), IBC and IRC all have allowed a designed connection in place of this. Per my 1976 UBC Section 2303. (b) “ Rationally. Any system or method of construction to be used shall admit of a rational analysis in accordance with well-established principles of mechanics.”
So if the three end nails can be design per the above “Rationally” then it is per the code. I can not see any code not allowing the engineer the ability to follow this. You may have to go back to the code the deck was to be designed under. Then calculate the loads to the connection and the allowable value for the three end nails, under that code, to see if the connection meets this.

Garth Dreger PE - AZ Phoenix area
As EOR's we should take the responsibility to design our structures to support the components we allow in our design per that industry standards.

 

[MiketheEngineer]

It is 2012 - why are you referencing a 1967 code - OR are you being an expert witness???

Three nails just doesn't cut it - by no means!! 22'' of water weighs about 110 lbs per sq ft. - usually well over the design limit of a deck!!

 

[jim57]

Yes. i need to determine if the water caused the collapse or would it have collapsed without the water and just a normal 40 psf load.

 

[hokie66]

Don't know about now, but the allowable load for a nail in end grain used to be 60% of that in side grain. But I agree that end grain detailing is poor practice. What was the condition of the nails? For a deck, probably corroded.

 

[jim57]

Yes the nails were rusted. The section of deck without the pool did not fail

 

[MiketheEngineer]

Like DUH - the pool at about 110 psf did it on a poorly constructed deck....

 

[msquared48]

Three thinge here:

1 End grain nailing is not only a nono, it is a nevernever! Side, top,or bottom only! No exceptions ever!!!!!!!!!
2. There was probably an inadequate shear nailing from the outside 2X to the inner one also.
3. There should have been a strap at the top, tying the two exterior 2X beams to the joists, to couter any rotational forces due to eccentric loading.

All this is only structural engineering common sense and a good standard of practice, irrespective of the requirements of any code.

Mike McCann
MMC Engineering

http://mmcengineering.tripod.com

 

[jim57]

Yes. I know all that has been discussed, but the person with the deck and pool is an engineer. He is indicating that we do not know what the code at the time was(which he does not know when (but after 1985). He is trying to say that it may have been acceptable. That is why I need more than good engineering practice. Thanks to all for your input.

 

[msquared48]

I designed things like that after 1985, and before for that matter, and it was never acceptable.

Mike McCann
MMC Engineering

http://mmcengineering.tripod.com

 

[hokie66]

What is the purpose of the investigation? Personal injury or just that the deck collapsed? It seems to me that the fact that the part of the deck without water is still there conclusively shows that the collapse is due to the water. The fact that the deck was poorly built and has deteriorated can be testified to by any competent structural engineer. You don't need a code for that. An exposed wooden deck which was built 25 years ago and not maintained is alway going to be suspect.

 

[MiketheEngineer]

Bingo to hokie66 - a deck built in 1965 is over 40 years old. A lot of people don't live that long - and wood surely won't - usually

 

[jim57]

Sounds easy, but when you have lawyers involved, sometimes you need to show it in writing.

 

[woodman88]

jim57 "Yes. I know all that has been discussed, but the person with the deck and pool is an engineer. He is indicating that we do not know what the code at the time was(which he does not know when (but after 1985). He is trying to say that it may have been acceptable. That is why I need more than good engineering practice. Thanks to all for your input. "

So per the 1988 UBC section 104 (d) “Maintenance. All buildings and structures, both existing and new, shall be maintained in a safe and sanity condition....” and “...The owner or his designated agent shall be responsible for the maintenance of buildings and structures...”

And this is pretty much the same in all the codes, to my knowledge. Did the owner comply with this?

Garth Dreger PE - AZ Phoenix area
As EOR's we should take the responsibility to design our structures to support the components we allow in our design per that industry standards.