Bridges

The Banora Point Upgrade Alliance (BPA) project involves an upgrade of the 2.5 kilometer length of Pacific Highway through Banora Point, in northern NSW. The proposed upgrade will provide a link between the existing Chinderah bypass and Tweed bypasses with the aim of providing freeway conditions, reducing congestion and travel times, and increasing safety. Key assets involved in the project include: bridges, pipe culverts, retaining walls, noise walls, sign support structures, drainage structures and fencing. The design life of major structures associated with the project such as bridges, culverts, retaining walls and inaccessible drainage structures is 100 years. Durability issues identified as relevant for major concrete structures within the BPA project environment included 1) Acid sulphate soil degradation; 2) Chloride-induced corrosion; 3) Carbonation-induced corrosion; and 4) Delayed ettringite formation. The focus of this paper is on the methodology for durability design of the Lake Kimberley pipe culverts, Landbridge over HW10 at Sextons Hill and thick concrete members against chloride induced corrosion, carbonation and delayed ettringite formation respectively.