Slide 18 of 45
- In wood framing, all connections need to have a nail, screw or bolt connecting two pieces together.
- Proper shear connections are created with combinations of fasteners, blocking and hardware such as framing anchors.
- Discussion of figure
- Example of a sliding failure
- Building looks good…..except for that it has shifted to the right
- It’s a good box, just slid along its weak link
- Shear forces pulled the two pieces apart
- Bottom of buildings – cripple walls – are often the weakest link
FASTENER TYPES IN SHEAR CONNECTIONS
- For nailed connections to be effective,
- Nails need to penetrate the wood to a certain depth.
- For this reason, the specified nail length must be used in all wood connections.
- It is important to use the proper diameter nail (common vs. box)
- It is important to avoid splitting the wood while nailing.
- What about screws?
- Screws should not be randomly substituted for nails.
- While screws provide superior holding power in tension, they have reduced ductility.
- Ductility is necessary to prevent brittle fracture during cyclic loading.
- Always consult the architect/engineer and the local building official when considering this substitution.