11 Lightweight Wood Truss Collapse

Question 1

Building codes define heavy timber roof construction as that in which the wood dimension is at least ________ wide and _________ deep.

Answer 1

4 inches / 6 inches

Question 2

What are the connections and fastenings made of for heavy timber?

Answer 2

Steel bolts and plates

Question 3

Lightweight wood trusses are made of 2x4s and are connected by what?

Answer 3

Gusset plates (sheet metal surface plates) or gang nails

Question 4

The main concern of the fire service is the __________________ used to connect the truss members together.

Answer 4

Sheet metal surface fastener

Question 5

In any structural element, the critical area subject to failure during fire is what?

Answer 5

The point of connection

Question 6

Three main issues with gusset plates:

Answer 6

1. Fire can char the wood and the 1/2” deep V-shaped nailing points can come out
2. Heat from flames can warp the thin sheet metal causing it to curl and pull out from the wood
3. Corrosion

Question 7

What is the rate of fire spread inside concealed spaces of lightweight wood trusses in comparison to conventional solid wood beam construction?

Answer 7

100% faster