Forbes Creek Road Bridge Replacement
During the 2019-20 disastrous “Black Summer” bushfires, Forbes Creek Bridge, situated near Bungendore NSW, sustained substantial structural damage due to the volume and mass of heavy vehicles responding to the severe bushfires in the area.
Following inspection in 2020, Queanbeyan Palareng Regional Council identified structural damage to the timber girders and abutments. Load restrictions were implemented on the bridge for an extended period of time whilst funding was acquired and the detailed design was undertaken.
In 2020, Reliance Engineering Services were engaged by Queanbeyan Palerang Regional Council to provide engineering and project superintendency services throughout the stages of project development and delivery. The detailed engineering design was completed by VLA Consulting Engineers.
Considering the urgency of replacement, the InQuik modular bridge design system was selected by Council. The project consisted of a single span concrete bridge, spanning 12m in total over Forbes Creek with an overall width of 7m. The efficient and lightweight design meant small cranes could be utilised within the narrow road corridor, avoiding the cost of constructing large crane pads. The bridge design system allowed for shortened construction times as minimal formwork and steel fabrication was required on site as the modular bridge units were delivered prefabricated. The seamless design provided greater quality control, ensuring precise steel placement and clearances to satisfy the structural requirements. The construction procedure minimised environmental impacts as minimal dredging was required within Forbes Creek.
The project was funded under the Disaster Recovery Funding Arrangement (DRFA) and the scope of works included:
Pre construction investigations including survey and geotechnical investigations
Detailed Engineering Design
Site Establishment
Implementation of Erosion and Sediment Controls
Constructing of a temporary sidetrack to ensure the road remained open to traffic throughout construction
Disassembling the timber bridge carefully to retain the heritage stone abutment walls
Piling works to support the construction bridge structure
Construction of InQuik modular bridge system
Installation of rock scour protection around bridge abutments
Reconstruction of road approaches
Installation of guardrail barrier systems
The functional design provides minimal maintenance costs, improve resilience to natural disasters and fire, improves safety and provides long-lasting benefits for years to come.
The project required meticulous planning and execution to overcome the numerous challenges presented by the location due to the narrow road corridor and requirement to retain the heritage stone abutment walls.
The project was successfully completed by HD Civil Pty Ltd and commissioned for opening in February 2021.
