Products

Determining Earthquake Loads

Question: 

We are currently developing a project which specifies “Seismic Design Category C.” We are an East Coast truss manufacturer and have not encountered seismic requirements before.

Scissors Truss Diagonal Bracing

Question: 

We are finding it difficult to design permanent diagonal bracing for scissors trusses. The truss is often only a few feet in depth, which does not provide adequate room for diagonal bracing. Has SBCA come up with recommendations for permanent bracing of scissors trusses?

Proper Storage And Shipping Of Trusses

Question: 

I would like to know the proper storage and shipping of wood trusses.

Sound Rating Information

Question: 

Do you have sound rating information for floor truss assemblies (i.e., STC and IIC ratings)? We are looking specifically for ratings for 12 in. floor trusses, with 1 and 1/2 in. concrete topping and without the topping. We are looking to meet the minimum code rating of STC 45 and IIC 45.

Lumber Species

Question: 

What type of wood is usually used for wood trusses? I live in Louisiana and I would guess pine, but I want to make sure.

Anti Trust Agreements

Question: 

I am looking for a set of guidelines or “rules” for members of the SBCA. Are truss plants really not allowed to speak of business matters? I think that is unfair. I'm not going to call up our competitor and tell them that they aren't charging enough and taking all the business. I just want all the truss plants in my area to get together and decide how we are going to do business. We need to standardize the industry.

Lumber Grades In Wood Trusses

Question: 

The grading rules usually permit some percentage of visually graded lumber to be below grade – I believe it is 5%. ANSI/TPI 1 requires that all lumber used in trusses be of the grade specified by the truss design. A strict interpretation of ANSI/TPI 1 would require that the fabricator cull the 5% that is off grade. What are your thoughts on this?

Truss Deflection Onto Non Load Bearing Walls

Question: 

I am installing a 40-foot scissor truss that is designed to deflect about ½ inch. I am concerned that the deflection will cause an interior partition wall to pick up some load from the truss and transfer it to the floor system. Should I double up the I-joists under this partition to pick up the extra load?

Snow Load

Question: 

I am a truss manufacturer in an area of the country that often has some pretty severe winters. It concerns me how little some of the local builders seem to know about snow load design. What are some of the things that need to be considered?

T-bracing

Question: 

The truss industry maintains that the design of truss roof and floor system permanent bracing is the responsibility of the building designer. System permanent bracing covers the entire structure and all bracing element interactions.