AISC Style Moment Connection 4

[dik]

I need to provide a moment connection to splice a beam. Space is limited and the entire length of beam cannot be installed in this existing building, so needs to go in 2 parts. Moment is always +ve and only need bolts on one side of the beam.

Does anyone see any contraindications for the connection (in sketch)

I propose to design?


4 bolts at the one side doesn't do it unless I go to 1" dia and not 3/4" dia (client's preference). I also note the AISC uses a CJP or PJP weld at the flange to the end plate. Any reason this cannot be a fillet weld?

Dik

 

[dik]

Attached is my nearly final program... note there is a difference between the AISC bolt tension calculation and the CSA S16.

Any comments or corrections appreciated... the data input is from a standard method I use. I have the data input as a bunch of 'sub-programs' that I cut and paste to build a larger program. It's efficient and allows me to build a lot of flexibility into the programs.



Dik

 

[dik]

and SMath copy...


Dik

 

[dik]

Does anyone know if this it the proper application for the limit bolt loading? As pointed out, the factor should be 0.75 and not 0.70.


Dik

 

[r13]

Your equation is valid for A325 bolt up to 1" in diameter. For above, Ft ≅ 80 kai, and Fu ≅ 92 ksi. Mu is the factored load moment.

My question: why is "2" in front of Mu, not "4"?

 

[r13]

I guess the 2 is due to effect of bolts in 2 rows. If this is the case, I suggest to define Mu' = Mu/# rows of bolt, and replace 2 by 4 in the equation for clarity.

 

[r13]

Dik,

Please check the statement "0.7 is to accommodate threads".

In AISC, F_NT (nominal tensile stress, 90 ksi) is used in place of Fu (specified minimum tensile strength, 120 ksi), it implies a 0.75 factor in between. But AISC uses the same F_NT regardless of threads are included, or not included.

Also, be aware the reduction in Fu for bolt diameter larger than 1".

 

[dik]

Sorry... it's 0.75; it has been my understanding that the 0.75 is to convert the Ab to the actual area of bolt due to the threads. Error corrected... didn't know that about the AISC. The Canadian code uses 0.75 on the Fu for the bolt and a phi for the bolt equal to 0.8. With Fu = 120 Ksi, the 75% brings it to the AISC value of 90 Ksi.


Bolt size in the array only goes to 1", thanks, much appreciated...



Dik