ABSTRACT
Underground stations are among the most complex design elements in transport systems, as they are required to provide an intuitive and welcoming space for users while coordinating a myriad of rail and building systems and facilities all within the underground real estate that comes with a significant price per cubic metre. Design of such stations takes years to identify, address and coordinate all multidisciplinary design issues. By the time the Sydney Metro West Central Tunneling Package station design for Five Dock was released for tender, the design of a station with binocular station tunnels was already well developed, so any major changes introduced significant risk to the project. When the design joint venture proposed a major change of a binocular arrangement to a single cavern, the proposal had to overcome numerous risks, including cost, settlement impacts, ventilation, and whether there was sufficient space for back-of-house facilities. Additionally, the impact on track alignment and user experience were carefully considered. The approach involved broaching the topic with the contractor and client, actively listening to, and addressing their concerns. Collaborative efforts among the client, designer, and contractor successfully addressed these challenges, resulting in an improved passenger solution at reduced cost. Lessons learned from recent experiences, such as managing large spans in shallow ground, in-formed the revised design. Contrary to the findings of the initial analyses, the single large cavern was proven to be of acceptable risk and more cost-effective. In conclusion, this case study underscores the importance of proactive risk management and innovative problem-solving in underground station design. By leveraging lessons from previous projects and driven to design new construction assets in a more sustainable way and optimizing its use, we can achieve superior outcomes while minimising costs.
