Test piling program for bridges on the Sunshine motorway in Queensland

The Sunshine Coast, the coastal region of Queensland just north of Brisbane, has experienced substantial growth in residential, commercial and light industrial development over the last decade. By the early 1980s it had become apparent that the road system within the area was unable to cope with the existing traffic, particularly during peak holiday periods. The Sunshine Motorway was proposed as a means of providing the road infrastructure necessary to significantly improve road conditions and to encourage future development of the Sunshine Coast area. Stage 1 of the Motorway was constructed using the 'fast track' approach and was opened to traffic in January 1990. The Motorway will be operated as a tollway. Eighteen bridges were constructed in Stage 1 of the Sunshine Motorway. Foundation investigation at several bridge sites revealed significant depths (> 50 m) of alluvial deposits. A test piling program using square reinforced concrete 'Balken' piles and the Pile Driving Analyser was carried out at these sites to establish optimum founding levels. Concurrent with the above program, the opportunity was taken to test the feasibility of driving long spliced piles consisting of an upper prestressed concrete pile section connected via the Balken mechanical joint to a lower 'Balken' reinforced concrete pile section. Two sustained load static tests were also carried out in accordance with AS 2159 - 1978 'SAA Piling Code' (A).