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Pre-Manufactured Truss Engineers

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abusementpark

Structural
Dec 23, 2007
1,086
Has anyone here ever worked as a pre-manufactured truss engineer (either wood or light gage steel)? I'm curious how much time these guys actually spend checking calcs and studying the plans. I guess after a while they must develop a good feel for what looks right based on different spans and spacings.

They must not be the ones actually inputing all the information into the computer program and generating the shop drawings. I am wondering much time is alloted for their actual review.
 
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Abuse-
I have never worked for a truss engineer, but when I was building homes for a living, my main truss supplier had their own "truss designer" in house. The designer was pretty good at picking different systems and doing layout work. She essentially "designed" the trusses empirically, then sent them out for an actual design to some other company that used Mitek software (or some such) to basically check the design.
As good as she was, sometimes I still had to tell her how I wanted/ preferred the trusses as there is usually many different ways to design the trusses.
I got the impression that there wasn't a whole lot of time spent on calcs or checking because the turnaround time was lightning fast. Sometimes I'd have truss shop drawings just a few days after a meeting with the designer, and the shops were coming from another company, not her.

My 2 cents....
 
The are more truss detailers than engineers in my country. I would not be happy stamping the drawings which most derailers produce these days
 
I did it for many years starting when the industry was still in its infancy in 1973. Back then - we used hand drawn "force" diagrams to find the axial loads of the members. I wrote some of the very first software packages that took over this tedious task. We went from doing about 3 drawings a day to over a dozen!!

Todays software is so detailed, complex and complete, I doubt that there are two dozen people in the US who could a complete one design in a day..

Today, a truss designer working in a truss plant, draws out or inputs the complete roof system to the program - not unlike a highly automated Auto-Cad type program.

The software using the previously entered loads, lumber sizes and grades runs all the calcs in a matter of seconds. This information can then be used for pricing. It will even supply a "cut list" electronically to the saws in the shop which are loaded and robotically make all cuts and label all members. The parts are delivered to an assembly table which often uses laser beam outlines that aid the builder.

But to answer your most pressing question - truss engineers will review hundreds of designs a day - 300 - 500 sometimes. And yes - you get very good at knowing what will/will not work.
 
We were approached by a truss manufacturer a few years ago. They offered $20 per job to seal the calcs that they produced. We turned it down- but this let's you know how much time would be budgeted per job.
 
I worked as a truss engineer for over 16 years, from the early 80”s to the mid 90's.
We never looked at a set of plans. As truss engineers we only designed the individual trusses per the loads shown on the truss design.
In the beginning I received, over the phone, the truss shape and loading (from the truss manufacturer) to design the trusses from. Then it was common on specialty trusses to do a quick hand calculation to see what would work before trying to design them on the computer. For the loading (gravity, wind & snow) we only made sure that it met the typical minimum loads required by the building codes.
Later the truss manufacturers would send in the computer input of the trusses (based on the our computer program they had) to the design and review. As the program was being updated and improved all the time. I created my own set of designs (which I had my calculations for and updated the calculations for the new capabilities they added) to check each version of the program.
Then in my review of the designs, I checked that the trusses met the design capability of the program and if any special load conditions were correctly inputted (per the computer input and not the plans which I did not see). The most time I spent reviewing them was on the truss to truss connections, when that became the truss engineer responsibility.
Now this is just how I did it. I am sure others have and do handle it differently.

Now one thing I have never understood is the lack of understanding of truss designs by the Building Departments and EOR's. This is even after the truss industries printed the truss responsibilities guild and the IBC/IRC printed the requirements for trusses in the code.

Garth Dreger PE - AZ Phoenix area
As EOR's we should take the responsibility to design our structures to support the components we allow in our design per that industry standards.
 
But to answer your most pressing question - truss engineers will review hundreds of designs a day - 300 - 500 sometimes. And yes - you get very good at knowing what will/will not work.

I hope you mean 300-500 truss designs, not 300-500 different truss jobs!

We were approached by a truss manufacturer a few years ago. They offered $20 per job to seal the calcs that they produced. We turned it down- but this let's you know how much time would be budgeted per job.

[surprise]

$20??? Does anyone know what is typical?
 
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