Design and verification of compression capacity of Continuous Flight Auger (CFA) Piles in Batesford Limestone for Surf Coast Highway Bridge

The Surf Coast Highway (SCH) bridge is a vital rail bridge constructed as part of the South Geelong to Waurn Ponds Duplication (SGWP) project in Victoria, aimed at eliminating the at-grade crossing. The bridge is 105m long and four spans, with the abutment and piers supported on CFA piles. This paper presents a comprehensive discussion on the geotechnical model and interpreted design parameters for the underlying Alluvial Terrace and Batesford Limestone formation. The author examines the conventional methods of assessing pile capacity in accordance with the Australian Piling Code AS2159-2009, FHWA, and VicRoads standard specification Section 607. The approach encompasses a detailed analysis of stability, serviceability, and estimation of structural actions for design, considering uncertainties in ground conditions, constraints with varying pile spacings, and potential reductions in design parameters. A comparative analysis is also presented, contrasting the measured load capacity with the predicted pile capacity, providing valuable insights into the efficacy of the design and construction methodology employed.