Choice of Timber connections

• The choice of fasteners for timber joints depends upon :

1. Degree of fixity required .
2. Force to be resisted .
3. Timber thickness
4. Speed of assembly .
5. Type & strength of timber .

Degree of fixity required

• Different fasteners have different deformation characteristics .
• A bolted joints slips more than a joint with a timber connector & a glued joints is the most rigid joint .

Force to be resisted

• Often the design load to be carried by the joint is the deciding factor in the choice of fastener .
• Nails are used for lightly loaded structures , bolts for moderately loaded & split rings or shear plates for heavily loaded structures .

Timber thickness

• Nails are suitable for thin members up to 50mm thick
• For thicker members , the choice will usually be bolts or bolts with connectors .

Speed of assembly

• If speed is the criterion , then prefabrication at the factory is the solution .
• Prefabrication is the most economical system if a great number of identical units are needed .
• Example: roof trusses with punched nail on plate pressed into the opposite faces of a joint by hydraulic press in the factory .

Type & strength of timber

• The type & strength of timber will determine the number of fastener required .
• Timber having similar joint strength are grouped together under MS 544 .
• There is a close relationship between timber density & joint strength : the denser the timber , the stronger is the joint .