Splice design for a WT section

[nishantnjoshi]

Hello,

I have not designed splice before. I would really appreciate if somebody can throw some light on splice design, in particular any material I can refer to design it.

Thank you.

 

[PittEng88]

You are going to need to provide a bit more information here:

What kind of splice are you looking to design? What forces does the member have to resist? What type of structure are you designing? Etc...

The more information you provide, the more accurate of answer you will get in this forum.

 

[spats]

I would probably splice using welded end plates, bolted together in the field. If the splice is in tension, be sure to figure prying forces. If the WTs are large enough, you could also use bolted splice plates for the flanges and webs.

 

[nishantnjoshi]

WT is 12 x 34.
Length of truss is 40 ft. Splice is at 14 ft. Elevation of truss is at 30 ft.

I have to provide splice at top and bottom chord of truss. So the splice will have to resist axial and shear force.

 

[structSU10]

Are you the connection engineer for a project, or are you the EOR for the project? A lot of times those connections are delegated designs for the fabricator, under the thought that they will supply the cheapest, most efficient connection. The EOR supplies the forces and checks the calculations by the fabricators engineer.

If you have to design this, figure the bolts and welds required based on your forces. the axial is generally assumed to act within the flanges/webs based on proportion of area. You should be able to find examples directly in the AISC example handbook (a free download if a member of AISC)

 

[KootK]

My take:

1) If you're dealing with significant tension in your splice, I like web/flange plates as shown below as the load path is quite direct and efficient.

2) In a truss, and especially in a compression chord, it's prudent to keep your splices close to your panel points. This suits strong axis chord flexure design and usually improves matters for both chord weak axis buckling and lateral torsional buckling.

3) In most respects, splicing a WT is the same as splicing a regular W-beam (I'll mention one difference below). Since W-beam splice examples will be much more common that WT splice examples, finding good W-beam examples might be the way to go.

4) If structSU10 and I are thinking of the same example manual, it's excellent and free for everyone, including non-AISC members: Link

5) Unlike a W-beam splice, it is quite difficult to achieve anything close to a full strength strong axis moment connection in a WT splice using conventional connections. For this reason, I'll often consider a WT splice to be a pin for strong axis bending. That doesn't prevent the joint from seeing some unintended moment, of course, so locating splices at low moment locations is prudent.

I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.