Field Assembly of Trusses
Field Assembly of Trusses
(OP)
I am looking at designing a 60'x120', 2 storey wood framed building. It would be preferable to use pre-engineered wood roof and floor trusses to span 60'. The building occupacy has many open space amenities including a gym space, etc... necessitating full clear spans.
Problem is ... this is to be constructed in a remote fly in community. They can have supplies delivered but not complete trusses, nor anything near 60' in length. I was wondering if anyone had experience with the field assembly of roof and floor trusses, if it is even recommended? If each truss member was cut and labelled before shipping to the site, once the ground floor was complete, they would have a large work area to commence site assembly of any trusses.
Any comments on whether this would be feasible? Is there a portable press that could be shipped to site to press the truss plates, or would it be recommended to switch to field plywood truss plates. Any comments appreciated.
Problem is ... this is to be constructed in a remote fly in community. They can have supplies delivered but not complete trusses, nor anything near 60' in length. I was wondering if anyone had experience with the field assembly of roof and floor trusses, if it is even recommended? If each truss member was cut and labelled before shipping to the site, once the ground floor was complete, they would have a large work area to commence site assembly of any trusses.
Any comments on whether this would be feasible? Is there a portable press that could be shipped to site to press the truss plates, or would it be recommended to switch to field plywood truss plates. Any comments appreciated.





RE: Field Assembly of Trusses
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.
RE: Field Assembly of Trusses
Mike McCann
MMC Engineering
http://mmcengineering.tripod.com
RE: Field Assembly of Trusses
It can be done... analysis by graphical means and plywood gussets. Used hardened truss gusset nails (stainless steel or HDG roofing nails can be used, they have a large diametre shank). Contractors laid out the truss on site and used plywood 'stops' for alignment of the members, neatly cut the web and chord members and nailed the gussets in place. Hoisting was done by hand and/or a small crane. As the span increases, this becomes more problematic. Can they 'barge' the construction material in? might consider using steel as suggested.
Dik
RE: Field Assembly of Trusses
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.
RE: Field Assembly of Trusses
Dik
RE: Field Assembly of Trusses
Currently have 4 ft. depth for floor trusses. Will see if we can get more, once I have had a chance to speak with the truss company and have a better understanding of the constraints. There is a possibility of providing an intermediate beam line for the floor trusses, however, would only reduce the spans to 10'/50', not enough in my opinion to discount the much cleaner solution of spanning the entire 60 foot distance. Design roof slope is 4:12, but likely could be altered if necessary. Design snow load is about 45psf so not terribly high.
As mentioned, steel may also be an option, however, I believe working with wood would be better suited to the local labour.
RE: Field Assembly of Trusses
Dik
RE: Field Assembly of Trusses
RE: Field Assembly of Trusses
I am starting to delve into Modular for other projects. Not an option here as I'm not aware of any modular unit that can be broken down sufficiently to fly into the site. We're looking at 2 stories, gymnasium (i.e. open span), etc...
RE: Field Assembly of Trusses
Watch the floor joists. If you just design to the max allowed deflection at this span you will have floors that flex so much that people will not want to walk across them.
= = = = = = = = = = = = = = = = = = = =
Plymouth Tube
RE: Field Assembly of Trusses
Analysis and Design of arbitrary cross sections
Reinforcement design to all major codes
Moment Curvature analysis
http://www.engissol.com/cross-section-analysis-des...
RE: Field Assembly of Trusses
RE: Field Assembly of Trusses
I can get you photos of required of the type of set up you could use.
Fearghus Quinn
Structural Engineer
Quinn Building Supplies Ltd
Northern Ireland
RE: Field Assembly of Trusses
RE: Field Assembly of Trusses
RE: Field Assembly of Trusses
RE: Field Assembly of Trusses
efsinc ... Floor live load would need to be 100psf for assembly type occupancy (public games rooms, hallways, lounges). Perhaps 50psf for a couple of small offices.