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“In
our company history, we don’t know of any failures on trusses that were
designed, manufactured, and erected properly.”
We don’t know of others that can make that statement.
Construction in our area was populated with many very good German builders who
conventional framed their jobs when our truss plant opened. We worked with
these builders, and they switched to trusses, except for a few old-timers who
did it the old world way.
So, can we make the statement that once you start to use trusses you never go
back to conventional framing, except for unusual circumstances!
We can say you will come back to trusses on the next job because it has the
advantage of expedience of erecting, uniformity, savings, etc.
You may ask strength-wise what’s the difference? Isn’t conventional framing
just as strong as trusses?
It should be but, how do you know if it is stronger? Trusses are designed with
2 3/4 to 3 times the design load as a safety factor. They are engineered and
tested to perform at that level. The conventional frame depends on how good the
person in charge of the framing is. Conventional framers depend on what seemed
to work in the past. In the past, you had to go through an apprenticeship that
turned out some very good master carpenters. Most framers don’t have formal
training today. Today, the better framers are made foremen’s and are frequently
do not get to apply their learned hands on skills
Let me point out the big advantages a builder has when he uses trusses:
¨ Architectural versatility
¨ Flexibility of interior partitioning and room
arrangement
¨ Uniformity in tolerances from one truss to the next
¨ Fast and easier erection time
¨ Lightweight (An estimated 20 to 40 percent less than
most other structural systems)
¨ Open web designs make it simpler to install HVAC air
and heating ducts as well as electrical conduits and other wiring runs.
¨ Can be inspected because design is documented
¨ The Total in-place cost results in savings.
¨ Durable---When trusses were first introduced in the
50’s in Florida, a common sentiment was, “Let the first hurricane hit and
trusses will be a thing of the past.” Such individuals did not understand that
trusses are composite systems and that when they are securely connected; they
will perform beyond their design loading conditions. When a hurricane did hit
in the Keys, the opposite happened. There was damage to conventional frame, but
none in trusses.
Truss systems have a proven performance record. An engineering report is
available on Hurricane Andrew, one of the worst hurricanes on record. An
official copy is available from WTCA. Basically, the report really says is that
whatever damage to the trusses, it was something else that caused the damage,
not the trusses.
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