Trusses with plywood plate. How to build?

[Siberian]

Hey,
This is my first time here. I live in Russia, Far East. I build houses. There is no factory that makes trusses in my region. So I make trusses on the building site. I use plywood plates, and fix it with nails and glue, instead of gusset steel plates. It is not a problem for me to get any truss plan with steel plates, and I would like to use plywood plates instead of steel ones correctly. So I have some questions:
1. Do I need to make plywood plates of bigger size, than the size of the toothed metal connector plate, shown on the truss plan?
2. What kinds of glue I can us?
I would be thankful for any information about trusses of this kind.

[Willie T]

You may find this site helpful:

http://images.google.com/imgres?imgurl=http://www.cps.gov.on.ca/english/be9000/be9101.jpg&imgrefurl=http://www.cps.gov.on.ca/english/be9000/be9101.htm&usg=__p_toQSO8kbGpq1s-DPvL5sNOcbk=&h=434&w=683&sz=70&hl=en&start=4&um=1&tbnid=PQL_D9_oxxXb8M:&tbnh=88&tbnw=139&prev=/images%3Fq%3Dbuilding%2Broof%2Btrusses%26um%3D1%26 hl%3Den%26rls%3DGGLD,GGLD:2004-20,GGLD:en

They anticipate you will already have their plans to work from, but maybe you can get a few ideas there.
*****************
When we find truss damage... we telephone the factory.
The first time, the factory sent a technician to do the work.
After first time, I tell them where damage is... they tell me how to install plywood repair gusset. (Yes, they later send official repair paper for officials to inspect.)

Trusses were first made, many years ago, with plywood gussets. These trusses still stand in many houses today. It is good construction. I do know that the glue is a Resin type glue. Plywood is usually 1/2" (12.7 mm)

[Don_P]

I'm just a carpenter so take it for what its worth. I've read somewhere that the steel nail plates have 80-100 psi shear capacity, remember there is a plate on each face. Figure how many square inches of plate are on each member and make sure your plywood gusset has an equivalent number of nails for that load. The plywood needs to be large enough to get the required number of nails in without splitting the wood, that's going to be a good bit bigger than the steel plate. To get the allowable load per nail I used this calculator. Hopefully I've got it set to plywood gusset in northern wood;
http://www.awc.org/calculators/connections/ccstyle.asp?design_method=ASD&connection_type=Lateral+loading&fastener_types=Nail&loading_scenario=Single+Shear&mm_type=Spruce-Pine-Fir&mm_thickness=1.5&mm_thickness_text=&sm_type=Plywood+%28other+grades%29&sm_thickness=0.46875&sm_thickness_text=&fast_dia=box&nail_size=6d&load_duration=1.0&wet_svc_factor=1.0&end_grain=1.0&temperature=1.0&diaphragm=1.0&submit2_LNS=Calculate+Connection+Capacity

If that link doesn't work the connections calculator is here;
http://www.awc.org/calculators/index.html
A 0.99x 2" fastener has 37 lbs of shear capacity in Spruce/Pine/Fir lumber. So, it would take at least 3 nails through 1/2" ply to equate to each square inch of nail plate connector.

You might want to explain your situation to the APA helpdesk and ask if they can point you to more resources.
http://www.apawood.org/

[mikec557]

I've done a lot of reading but it never seems completely clear to me. When making the truss using 1/2 plywood as the gusset/plate, do you put the plywood on both sides of the truss?

My goal is a simple 2 foot rise in a 6 foot run (4x12 pitch), then put some purloins on the top and cover with corragated polycarbonate patio cover style material.

Thanks for any advice or answers.

Mike

[AUGER]

plywood plates are in a general sense at least double the size of metal connector plate.
and in area's of high snow loads 3/4" plywood is used more often than 1/2" ply.

the actual size of each plate must be determined by calculating the forces in the particular joint.. and the size of the plate is to basically to allow for enough nails to
take up that force....
the number of rows of nails and the on center spacing in each row is the more important part...especially when it comes to the chords or webs splitting due to the installation of the nails...

for a run of common trusses it should be relatively inexpensive to have an engineer calculate the size of the plates/number of nails and the nail spacing....

Auger