CASE STUDY ––––––––––––––––––––––––– Northlink WA Stage 1 - Southern Section Perth, WA, Australia Reinforced Earth® TerraTilt® Abutment & Retaining walls Owner: Main Roads WA Consultants: Aurecon Contractor: John Holland Pty Ltd Construction: Nov 2016 - Jan 2018 Background Challenges The $1.02 billion NorthLink WA - Re-design an in-situ counterfort Project, jointly funded by the retaining wall to a Reinforced Federal and State Government, Earth® wall that can takes traffic off local roads and accommodate large horizontal onto the Tonkin Highway. This traffic barrier loads. means local roads will be used for - Large horizontal bridge loads local traffic and those who live and - Architectural finish, circle pattern work locally will experience a safer, - Curved abutment panels with more peaceful environment. It also architectural finish, circle pattern provides an efficient alternative freight route, taking about 80 per Solutions cent of trucks away from the Great RECO was able to develop a modified Northern Highway. traffic barrier and Reinforced Earth® wall interaction that restrained any The southern section of Northlink horizontal loads from the traffic WA provides a freeway-standard, barriers being transferred to the wall free-flowing link from Collier Road itself. through to Reid Highway via Tonkin Highway. The system incorporates a column and capping beam that the traffic Works included: barrier is cast on top of. The capping - Grade separations at Benara beam has soil reinforcement Road, Morley Drive and Collier connected to it and it is this, along Road with the columns, that restrain the - 4m wide shared path along horizontal loading. Tonkin Highway from Guildford Road to Reid Highway Due to traffic barrier loads not being transferred to the wall, we were able The Reinforced Earth Company to use our standard TerraTilt® panel (RECO) was awarded the design design with optimised thickness and and supply of the abutment walls at reinforcement. Overall, this Main: Reinforced Earth® TerraTilt® walls at Morley Drive Intersection the Morley Drive and Benara Road optimisation significantly reduced the Above first picture: Columns for the traffic intersections as well as additional client’s costs for the wall, especially barriers were formed using a spiral duct Above second picture: Capping beam setup retaining walls. The total of when comparing it to the original for the traffic barriers Reinforced Earth® walls supplied design of an in-situ counterfort wall. Above third picture: Reinforcement of the columns extending into the capping beam for the for the project was 4788m2. traffic barriers Above on the left: Reinforced Earth® TerraTilt® walls at Benara Road after completion Above on the right: Reinforced Earth® TerraTilt® walls at Benara Road showing curved wingwall and straight abutment, both with matching pattern Project specifications Significant design checks were The architectural finish on the –––––––––––––––––––––––––––– carried out to ensure the capacity of curved wingwalls of the Benara System TerraTilt® the column and capping beam soil Road abutments was achieved –––––––––––––––––––––––––––– reinforcement system was adequate using a steel mould that was Finish Circular architectural for restraining the traffic barrier loads. fabricated specifically for the finish on both flat and project to ensure the radius of the curved panels Similarly, soil reinforcement was required curve was met as well as –––––––––––––––––––––––––––– connected to the capping beams at the positioning of the circular Structures 6 x Reinforced Earth® each bridge abutment to restrain the pattern across this curve. Bridge abutments, 3 large horizontal loading caused by Reinforced Earth® braking vehicles. Conclusion retaining walls By removing the traffic lights and –––––––––––––––––––––––––––– To achieve the architectural finish, creating the grade separations Area 4,788 sqm (total) patterns were laser cut out of steel along Tonkin Highway, traffic flow –––––––––––––––––––––––––––– plate and welded to 12m flat casting has improved, leading to safer and Max. Height 9.8 m beds. This resulted in an accurate, quicker journeys for commuters, –––––––––––––––––––––––––––– identical pattern across all of the residents and the freight industry. Design load 20kPa surcharge panels. Horizontal Bridge Loading Traffic Barrier loads –––––––––––––––––––––––––––– Design life 100 years Below: Reinforced Earth® walls at Morley Drive –––––––––––––––––––––––––––– Reinforced Earth Pty Limited Reinforced Earth Limited Level 4, 20 George Street PO Box 72 734 Hornsby NSW 2077 Australia Papakura Auckland New Zealand Ph +61 2 9910 9910 Ph +64 9 236 3385 Fax +61 2 9910 9999 Fax +64 9 236 3385 www.reco.com.au www.reco.com.au .