Fasteners - hdgasa

Stephen’s Corner25-30% of total building costs, theadditional cost of galvanizing reduces tobetween 1.5-3.0% of total building cost.However, by galvanizing only certainvulnerable or critical elements, e.g.surface panels, the additional cost ofgalvanizing reduces further still, perhapsto as little as 0.5-1.0%.These percentages, of course, relate onlyto total construction costs and whentaken against total project costs or finalselling prices the added cost ofgalvanizing becomes very small indeed,often less that 0.2%. This represents avery small fraction of the cost of repairsshould unprotected reinforcementcorrode. Similar costing analysis hasbeen reported on a number of occasions.Applications of galvanizedreinforcementin a variety of reinforced concretestructures and elements. The rationalefor this is based on the philosophy thatthe coating provides a safeguardagainst early or unexpected corrosionof the reinforcement. Should suchdamage occur costly repair andremediation of the structure may benecessitated in order to realise the fulldesign life of the structure. Thisrepresents an ever-increasing economicburden and the redirection of scarceresources.Particular circumstances where thegalvanizing of reinforcement is likely tobe a cost-effective and soundengineering decision include:◆ light-weight precast claddingelements and architectural buildingfeatures;◆ surface exposed beams andcolumns and exposed slabs;◆ prefabricated building units such askitchen and bathroom modules andtilt-up construction;◆ immersed or buried elementssubject to ground water effects andtidal fluctuations;◆ coastal and marine structures;◆ transport infrastructure includingbridge decks, roads and crashbarriers; and◆ high risk structures in aggressiveenvironments.Many examples exist around the worldwhere galvanized reinforcement hasbeen successfully used in a variety oftypes of reinforced concrete buildings,structures and general construction.Some prominent, world-wide examplesare shown in Figures 2-5.Finally, it is noteworthy that in theState of the Art Report on CoatingProtection for Reinforcement (ComiteEuro-International du Beton, 1992) theGalvanized steel bar and other fittingsincluding bolts, ties, anchors, dowelbars and piping, have been widely used continued on page 40...Volume 8 Issue 1 2011 Hot Dip Galvanizing Today 39