jack truss connection to girder truss

[jgeng]

Do you find jack trusses are only connected to girder trusees by toe-nailing? shouldn't bearing be provided with a hanger? Is this connection typically the buidling engineer's responsibility or truss engineer?

 

[a2mfk]

I don't allow toe-nailing and require a pre-manufactured truss connection. My experience in the field with toe-nails is they are difficult to do properly, particularly with a jack truss at an angle, and the final result is unpredictable at best.

I also specify all TRUSS TO TRUSS connections to be designed and specified by the TRUSS ENGINEER. I had too many experiences early on in my career where the truss designer changed the layout I had originally predicted on my dwgs which created a large headache after the dwgs were done.

But all the truss connections to the main structure are specified by the EOR. I put a note that some of the connections may be modified based on the final truss design package. As stated above, they may change the layout to be more economical and I gave up predicting what that may be...

HTH,
Andrew Kester, PE
Florida

 

[Den32]

A2mfk is Correct. "Truss to Truss Connections' should be by the Truss Engineeer. You can find this literature in the Metal Plate Truss Manufacturer's Code of Practice somewhere.

I have seen both toe-nailing and hangers. It really depends on how long the jack trusses are and the deisgn loads (wind, snow, etc.).

Sim to what A2mfk said, toe-nails can have installation issues (can damage wood, etc.) plus over time the wood will shrink and pull these nails with it. 'Basic' hangers (not skewed/sloped) are not that expensive for these low loads.

 

[rscassar]

Jack truss to girder truss should be detailed by the truss engineer. I would also request that the truss engineer submits their details prior to fabrication. In my region, the truss engineers are not certified engineers and it makes me uncomfortable knowing that they are distributing construction documentation.

 

[abusementpark]

Not only do we make the truss supplier design all truss to truss connections, we make them design all truss tie down connections to the structure.

 

[Ron]

Toe-nailing should be disallowed by code. It is rarely done properly and is a holdover from times when uplift was not a significant consideration. Toe-nailing does not adequately accommodate stress reversals, which are common in structures, particularly roof structures.

 

[JAE]

I posted this link sometime back (2004) so its a little dated but it summarizes the state of Nevada's views on wood truss design responsibility (truss designer vs. EOR).

Nevada newsletter link