Lengthening of Bridges for the Southern Expressway Duplication: Challenges Faced in the Design and Construction
- Publication no: ABC-DES901-14
- Published: 22 October 2014
The Southern Expressway Duplication project is a 19 km duplication of the current reversible flow single carriageway road to a duplicated two carriageway road allowing improved traffic flow for future urban growth to the south of metropolitan Adelaide. The project required 20 existing bridges to be widened, duplicated or lengthened and one new flyover bridge to be constructed. Kellogg Brown & Root Pty Ltd (KBR) and subconsultant Hyder Consulting Pty Ltd were the designers engaged by contractor Baulderstone Abigroup Joint Venture (now Lend Lease Engineering Pty Ltd) for the Department of Planning, Transport and Infrastructure of the South Australian Government.Five concepts were developed for lengthening the existing steel girder and concrete composite deck road overbridges. The selected design involved temporary propping while the existing bridge was demolished and the lengthening took place.The main design challenges of these overbridges involved traffic management, services, design of new abutments, bridge articulation, splicing to existing girders and modification of existing reinforced soil structures. The methodology for lengthening pedestrian bridges was another design challenge with a novel design solution.Detailed design was split into design packages, and early works were fast tracked to take advantage of more favourable months for construction.