Civil Infrastructure Specialists

modification of a manhole where two main sewer branches converge into the trunk sewer main.

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modification of a manhole where two main sewer branches converge into the trunk sewer main.

Barwon Sewer Restoration (BSR) was contracted for a critical project involving the modification of a manhole where two main sewer branches converge into the trunk sewer main in Geelong. The project was necessitated by the construction of a new road over the manhole, which was originally built in 1968. Due to the age of the structure, original design and as-built drawings were missing, leaving the structural capabilities and potential corrosion issues of the manhole unknown.

Scope of Work:

Assessment and Testing:
- 3D Scanning: Utilized to create detailed models of the existing manhole structure.
- Reinforcement (Reo) Scanning: Conducted to identify the location and condition of reinforcement within the concrete.
- Concrete Testing: Performed to determine the integrity and strength of the manhole walls.
- Breakouts and Inspections: Carried out under confined space entry with full breathing apparatus to examine internal conditions and confirm the structural integrity.
Structural Report:
- A comprehensive report was compiled based on the assessments, confirming the manhole’s structural suitability for modification and road construction.
Modifications:
- Lowering the Pit: Adjustments were made to the manhole’s height to accommodate the new road level.
- Custom Coated Pre-Cast Converter Slab Installation: A new slab was installed below the road pavement, tailored to withstand the environmental conditions and provide necessary structural support.
Road Construction Integration:
- Mr. Manhole Leveling System: Employed to ensure the road could be built over the manhole while achieving proper compaction, without complications from the existing 600mm sewer manhole opening.
Final Adjustments:
- Mr. Manhole Corer and Leveling System: Used post-asphalt layer completion to install a fully corrosion-resistant chimney and lid, precisely leveled with the surrounding asphalt surface.

Outcome: BSR successfully completed the project, allowing the road to be constructed over the manhole with confidence in its structural integrity and corrosion resistance. The use of advanced scanning and testing technologies ensured a thorough assessment, and the innovative leveling system facilitated seamless integration with the new road infrastructure.