Belmore Bridge Sewer Rehabilitation: Applying Trenchless Technology Above the Ground

Abstract

Belmore Bridge crosses the Hunter River and connects the suburbs of Lorn and Maitland. In October 2000, a DN450 DICL sewer rising main was installed across the bridge. A 2023 condition assessment found the pipe was extensively corroded, much more than expected for its short life. When renewing aboveground sewer infrastructure, the obvious choice might be to remove and replace it – there’s no ground to contend with. In this case, and countless others across Australia, the pipeline crosses a body of water. Cutting into and removing pipe infrastructure risks sewage spilling into a sensitive environment. Trenchless technology mitigates this risk. This project proves that trenchless technology can be applied in challenging above-ground situations, retaining the same benefits realised in below-ground applications. This paper will discuss how rehabilitation methods like die-reduction lining (also known as swage lining) are viable options for sewer rising mains running over water, bridges, or in other sensitive environments. The unusual location of the pipe – a bridge – added complexities for the project team. During a typical die-reduction lining installation, the stretched pipe produces a significant amount of load force that acts compressively on the host pipe. This usually isn’t an issue because the force is transferred harmlessly to the surrounding earth. In this case, all the force would be acting on the pipe, bridge, and pipe supports. As well as the benefits of using trenchless technologies above ground, this paper explores how the delivery team contended with the different forces that would be acting on the bridge during works and after renewal, and mitigated this through their design and methodology. 1 No-Dig Down Under 2025 Belmore Bridge Sewer Rehabilitation: applying trenchless technology above the ground Nick Rauch and Allan Moran