Truss Reactions

[JStructsteel]

So got truss reactions as a lump sum, i.e. not broken into DL, LL, WL, etc.

Is it worth figuring out the components, or just design for the total reaction using ASD?

I asked for the component reactions, but got no reply.

Thanks

 

[XR250]

I just use ASD.

 

[phamENG]

Yeah, I don't think the MiTek and other similar softwares are capable of breaking it out. And you're not working with an engineer - it's a designer who may be very knowledgeable (@RontheRedneck ) or may have no clue what load combinations are. The engineer is just rubber stamping the output after the fact. They probably couldn't tell you where a single truss they've "designed" is going to be installed.

Just apply it with ASD and roll with it. If you have complex framing with lots of transfers, then it might benefit you to work out loading for yourself so you can break it down.

 

[Eng16080]

I'd probably break it down into the components. This will also serve as a good double check of their loads/reactions.

 

[RontheRedneck]

No one has ever asked me for reactions to be broken out before. The program does not give us any control over what appears on the drawings.

It might be possible to get them by printing out calcs for each load case. I've never tried it. If I think of it tomorrow I'll give it a shot.

 

[EngDM]

No one has ever asked me for reactions to be broken out before. The program does not give us any control over what appears on the drawings.

It might be possible to get them by printing out calcs for each load case. I've never tried it. If I think of it tomorrow I'll give it a shot.

In Canada where we use LSD we get them broken up by type all the time. If/when you guys ever switch to LRFD only, you'll likely see more of this.

 

[RontheRedneck]

Just for the heck of it I ran a 40' truss today. This is what the program came up with for a shop drawing.





There's an option to print calcs to a PDF file. You should find it attached if you care to take a look. But it's almost 40 pages of stuff based on all the load cases. And for the most part reactions are not spelled out.
.

 

[SE2607]

Maybe I am oversimplifying the problem, or maybe I'm just dumb, but can't one just take the tributary load to one truss and use statics to get the reactions by load case?

 

[EngDM]

Just for the heck of it I ran a 40' truss today. This is what the program came up with for a shop drawing.


View attachment 7684


There's an option to print calcs to a PDF file. You should find it attached if you care to take a look. But it's almost 40 pages of stuff based on all the load cases. And for the most part reactions are not spelled out.
.

Can't you just take the VERT(TL)-VERT(LL) to find VERT(DL) anyways with this? It basically is broken up into components.