F203 PBS Structural Materials

Timber; very versitile and acceptable structural element in comparison.

key notes.

• strong in tension and bending
• high strength/weight ratio
• Durable (with proper protection)
• easy to work with
• low modulus of elasticity (change shape under load) poor conductor of heat
• fire resistance of large structural elements is ok
• low embedded energy costs, rising energy cost makes timber an economic alternative

timber selection is based on its strength which is variable from species and from within species.

specification for use can be either

• stress grade (quality), this can be undertaken by eye, more commonly, mechanically, measuring its deflection, the modulus of elasticity can be measured and its strength estimated
• strength classification; softwoods are weaker, and the weakest cannot be used for structural purposes, hardwoods are less often used due to their slow growing nature and related expense.

specification may be made of other properties ie resistance to fungal attack.

timber is produced in standard sizes and is more economical if specified thus.

connectors:

• nails,screws,bolts,tooth plate and split ring connectors, glue, timber to timber, gang nailed

note spacing regulations to avoid splitting, bolts require washers

Masonry (bricks & Mortar) performs may of the tasks associated with a building in addition to the structural element

widespread use…