Advanced Structural Designs

ACN 097 789 87 92 Vasey Cres CAMPBELL ACT 2612

Telephone 61612171 Facsimile 61612170

Email mal@structuraldesigns.com.au

What changes need to be made to a typical Canberra specification for work at the coast?

Aside from the usual changes we make for earthquake category and wind speeds you might like to consider the following durability issues. These are not so much a wish list as they are codified requirements. The implication is, if they are not specified the building owner would be entitled to sue for damages.

Example below is outside splash zone but within 1km of a surf beach

Steel Protection

>10 years <20 years to AS/NSZ 2312;1994 (you could specify 5 to 10 years)

Painted LP1 to LP6

Galvanised GZLP

Concrete Strength and cover external (exposed) - AS3600

40MPa with 45mm cover or 50MPa with 35mm cover

Masonry Unit - salt attack resistance grade - Exposure - ASNZS 4456.1

Mortar durability M4 (see table 10.1 AS3700)

Brick wall ties connectors and accessories

Wall ties R4 (Appendix F AS3700) must be stainless steel.

Lintels and shelf angles R4 (Appendix F AS3700) must be stainless steel painted to comply with table F5.

Brick reinforcement R4 (Appendix F AS3700).

Grout in reinforced blockwork minimum cement content 300kg/m^3 other requirements to meet clause 10.7 of AS3700.

Reinforcing steel in blockwork minimum grout cover 30mm

Exposed fasteners on decks and pergolas – Stainless steel

This list is by no means exhaustive and you will need to consider all of the usual problems associated with corrosion of dissimilar materials as these can progress very rapidly in the presence of chloride ions. A good example of this was a case we looked at where someone had used plated steel bolts to fix aluminium handrails. The base connection lasted less than six months and the handrail failure could easily have resulted in a death.

If you need a practising structural engineer in Canberra ACT to check that you have covered all bases call Advanced Structural Designs on 02 61612171.