Need a book? Engineering books recommendations...

Return to index: [Subject] [Thread] [Date] [Author]

Re: Premanufactured wood trusses without

[Subject Prev][Subject Next][Thread Prev][Thread Next]
This sounds similar to a thread we had a few months back concerning pre-
engineered trusses in general.  I mentioned this same item in one of my
responses.

Here are the general sense of what unfolded.

1.  I questioned the rectangular web area left for a "storage room".   I was
told the truss was modeled on a computer and therefor was ok.   I stated that
I could stack marbles to the moon on a computer.  I firmly beleive in
computers, but will never accept their output as correct until they come up
with a "common sense" chip.

2.  I inquired with the truss supplier (the local lumber supply) if unbalanced
loading was consider.  He did not know.  He asked the firm that supports his
company (the truss program people I guess).  

3.  I told them I wanted written confirmation from a registered engineer that
the trusses were designed for unbalanced loading and were stable.   They never
answered my question directly, however, they did change the trusses and add
heavier plates.    I was not the EOR, but the contractor asked me to look into
the roof for him, he felt uncomfortable with it.  The truss was a 40'
clearspan.  They also used some interior walls for bearing that previously
were not used as bearing in other areas of the building.

4.  In talking with the lumber yard people, I realized, they know very little
about the actual working of the program.  I also question some of the logic
used in formulating the computer code itself, such as:
    a)   does the program immediately just calculate joints loads and apply
them at the joint
   b)  what combinations of loads are being checked
   c)  those joints at midspan of the bottom chord; in between diagonals; I
see them all the time and do not know whether the program treated them as
hinged or fixed.

my 37 cents
Ron Martin