Kalbarri Skywalk
Stainless steel has contributed to one of Western Australia ’ s architectural masterpieces overlooking the Murchison River Gorge .
Kalbarri National Park is located approximately 550km north of Perth in Western Australia and is dubbed as one of the state ’ s best scenic nature destinations . Delivering a major tourism boost for the Mid-West region , the Western Australian State Government with the Department of Biodiversity of Conservation and Attractions opened the highly anticipated Kalbarri Skywalk in June 2020 . The skywalk allows visitors to immerse themselves in breathtaking views of Murchison River Gorge and the natural beauty of the surrounding landscape . Two cantilevered viewing platforms ‘ float ’ mid-air 100m above the canyon , with one platform projecting 25m and the other 17m beyond the cliff face . Offering extensive 270-degree views from the highest point in the gorge system , the skywalk platforms were built and anchored into the 400-million-year-old sandstone .
Unique experience The inspiration behind the skywalk ’ s architecture and materials selection was to deliver a unique wilderness experience without detracting visitors from connecting with the natural environment . Designed by Eastman Poletti Sherwood Architects , the skywalk is 40km inland from the coastline and merges elegantly into the rocky gorge country and its geological features . Built by Bocol Constructions , the skywalk and surrounding tourist infrastructure make extensive use of coloured patterned concrete and rust-coloured weathering steel to blend in with the surrounding landscape . Over 200m of grade 316 stainless steel handrails complement the structure , delivering safety and stability for visitors . ASSDA Member International Corrosion Services ( ICS ) was engaged to perform the chemical surface treatments on the stainless steel handrails , which included 128 units of 25mm rectangular hollow sections ( RHS ), ranging from 1100mm – 1600mm in length . Fabricated and delivered by Bouvard Marine , the stainless steel material for the project was supplied by ASSDA Member Stirlings Performance Steels . All sections underwent a post-fabrication , two-stage surface treatment process – chemical pickling , followed by electropolishing . Firstly , the sections were pickled and passivated in accordance with ASTM A380 Standard Practice for Cleaning , Descaling , and Passivation of Stainless Steel
Parts , Equipment , and Systems as a pre-electropolishing treatment . This involved immersion of the sections in chemical baths of up to 30 degrees Celsius to remove surface contaminants and heat-affected zones . The sections were then dried , in preparation for the electropolishing process which was performed in accordance with ASTM B912 Standard Specification for Passivation of Stainless Steel Using Electropolishing . Each section was suspended by contact points from an anode and immersed into an electropolishing bath at a set current for optimum corrosion resistance and to ensure an even and smooth finish ( R a value ). The sections were then drained , carefully washed , air-dried , and individually wrapped to ensure no damage occurred during the six-hour on-road transport to Kalbarri National Park . All post-fabrication surface treatments were performed at the ICS workshop in Forrestdale . A certificate of conformity was issued to the client by ICS to verify the completed treatments complied with the international standards specified . The pickling , passivation and electropolishing treatments
18 Stainless Steel World April 2023 www . stainless-steel-world . net