Scissor Truss Connection To Top Plate
Scissor Truss Connection To Top Plate
(OP)
Could someone please clarify what is the correct way to detail the connection between the scissor truss and stud wall top plate. I have read several threads on this website regarding this, but it doesn't seem like there has been any clarification.
Is it incorrect to provide connection at both ends of the scissor truss to prevent lateral thrust assuming that the wall would move with the truss. My thought is to install the connections after the dead load has been placed.
The project I have this on is a 40' x 80' church located in the middle tennesse area. 2/3 of the roof is scissor trusses and the other 1/3 is common roof trusses.
My huge dilemma is over the top plate connection and top plate design.
If anyone has encountered this problem, please help shed some light.
Thank you,
Val
Is it incorrect to provide connection at both ends of the scissor truss to prevent lateral thrust assuming that the wall would move with the truss. My thought is to install the connections after the dead load has been placed.
The project I have this on is a 40' x 80' church located in the middle tennesse area. 2/3 of the roof is scissor trusses and the other 1/3 is common roof trusses.
My huge dilemma is over the top plate connection and top plate design.
If anyone has encountered this problem, please help shed some light.
Thank you,
Val





RE: Scissor Truss Connection To Top Plate
RE: Scissor Truss Connection To Top Plate
Anyone else have any thoughts? You've got me curious here Val, please let me know how it's worked out...
Cheer,
YS
B.Eng (Carleton)
Working in New Zealand, thinking of my snow covered home...
RE: Scissor Truss Connection To Top Plate
RE: Scissor Truss Connection To Top Plate
Sometimes other elements of the structure will be installed after the trusses are set, but before thetruss end connections are installed. These other elements may not provide enough clearance to install the remaining items to complete the truss connection.
Both youngstructural & bjb have good advice. In practice when I design a scissor truss I try to limit the horizontal deflection to a limit that in my judgement is acceptable.
The important thing is to work with your truss supplier and draw on their experience.
RE: Scissor Truss Connection To Top Plate
RE: Scissor Truss Connection To Top Plate
RE: Scissor Truss Connection To Top Plate
I looked into elastomeric bearing pads like the ones used in bridges, but didn't come up with too much: I determined that I would not actually have enough shear force to cause the pads in question to deform laterally. (although you'd think there would be a product out there somewhere that could do this.)
However, I did find bearing pads which could have a thin, specially-polished stainless-steel plate fabricated on one side. Landing the end of the beam with another polished steel plate, I could have a near-frictionless slip condition allowing the roof scissor trusses to spread under the 130 psf snow load.
However, these roof trusses land on ridiculous large beams: like 8"x16" or 12"x24", not walls, so the conditions may not apply. For wind & seismic, the roof diaphragm spans between neighboring wings of the house.
Pretty sick.
SeattleMike