Wood Girder Tiedowns 1

[BSVBD]

I recently posted a “Rule-of-Thumb” stating “you furnish the steel, you furnish the fastener”.

I would think that wood truss and girder manufacturer and suppliers should do the same.

With varying general contractors, I've seen varying practices.

Who is the responsible specifier of wood girder tiedowns - The engineer of record or the girder supplier?

Opinions?

Thank you!

 

[KootK]

The wood truss industry, in which I was previously immersed, definitely thinks that it's the EOR's responsibility. They say so in their standard practice docs etc. Truss to truss connections by supplier, truss to other stuff connection by you. Similar to steel and other delegated design items. The arguments for that are:

1) Truss guys don't know your building design well enough to be confidently moving load around outside of the scope that they control.

2) Truss guys want their own liability to end someplace, preferably before the foundation.

In practice, #1 isn't really true. The truss guys mostly do know what needs to be done. And, on the flip side, it can sometimes be difficult for EOR's to spec the connections without the details of the truss while, if the EOR drawings are complete, it's pretty straight forward for the truss guys to do their bit.

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.

 

[dik]

If they're spec'd or shown on the drawings, then it is an issue for the General Contractor to sort out... not the EoR...

Dik

 

[JAE]

The provisions below came from the Nevada board newsletter back in 2004.
Not sure if the truss industry or engineering entities have adopted any of these formally:

Basis of Design
1. Premanufactured roof trusses are an engineered system - that is, each truss has a specified location in the overall structural system.
2. The premanufactured roof truss system is both a vertical and lateral load system.
3. The lateral load forces must be developed by the EOR and given to the truss engineer to design (drag truss load, collectors, etc.).
4. All truss-to-truss connections are the responsibility of the truss engineer.
5. All drag load (horizontal truss transfers) connections between the truss and the structure are the responsibility of the EOR.
6. All truss-to-structure (walls or beams) connections are the responsibility of the EOR.
7. It is the responsibility of the truss engineer to develop the loading required to implement the requirements of snow load Appendix A.
8. It is the responsibility of the truss engineer to review all of the EOR’s design specifications, roof truss support, and drag details and to incorporate these requirements into the engineering design of the roof truss system.

Required Information from Truss Engineer:
The truss engineer should develop a truss layout plan for the truss system that clearly indicates the truss vertical support conditions, truss-to-truss connections, drag trusses and collectors, and any other field-installed reinforcement, including field-installed top chord reinforcement at eaves necessary to execute the truss system design. The truss roof framing plan should be sealed by the truss engineer and be included with the individual truss cut sheets. The truss engineer should also provide proper supervision of any truss company technicians.

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[dik]

Thanks JAE... good summary.

 

[BSVBD]

Thanks JAE... good summary.