Bridges

Wallaga Lake Bridge, a timber girder bridge on MR272 from Bega to Tilba Road, accommodates single-lane traffic. Constructed in the 1890s, the bridge comprises nine timber beam spans, each approximately 9.5 meters in length, with an overall length of 95.09 meters and a width of 5 meters.

The original bridge includes four timber girders, transversal timber decking, and longitudinal timber sheeting. The pier configuration features single trestles with 4-6 piles per pier, with driven timber piles supporting timber headstocks.

The bridge underwent significant rehabilitation despite numerous constraints and challenges. A Level 2 inspection in August 2018 identified critical defects, resulting in a load limit of 22.5 tonnes since October 2018. Challenges included community resistance to closing the bridge, carrying out the rehab, sensitivity to Aboriginal and heritage land, environmental concerns due to its location within a marine park, the presence of microbats, and the impact on local businesses and schoolchildren.

Key objectives were to strengthen the bridge's substructure and superstructure, ensure the bridge's capacity to carry a single lane of GML load traffic (42.5 tonnes), and improve serviceability and durability. The project was executed in two stages to minimize extensive closures. Stage 1 focused on substructure rehabilitation, where existing piles with significant splits and decay were wrapped with CFRP jackets and marine-grade epoxy grout (PILEMEDIC) to prevent further splitting. Stage 2 involved the full replacement of the superstructure, including headstocks, cross beams, corbels, girders, transverse decking, and longitudinal sheeting. Environmental impact was minimized through meticulous planning and execution.

Despite the challenging constraints, the project achieved its objectives by leveraging advanced engineering techniques and community engagement. The successful rehabilitation of Wallaga Lake Bridge preserved a vital transportation link while ensuring the safety of the local community and environment. This project serves as a model for balancing infrastructural development with environmental and community considerations.