- Design, manufacture and installation of a cofferdam structure which acted under a double mandate; allowing remedial headstock to work independent of tidal movement while transferring bridge deck loads to piles
- Bridge steel bearing abrasive blasting and coating
- Headstock Strengthening – Hydro-demolition of defective
concrete, reinforcement augmentation, surface preparation
(CSP8 finish), and installation of a new concrete jacket with reinforcement. - Installation of Sacrificial Anodes for Cathodic Protection (SACP) including water anodes and monitoring through junction boxes at each pier
- Concrete silane treatment (MasterProtect H1100) and concrete Anti-carbonation coating (MasterProtect 150 Bridge Grey) above high water level on abutments and piers.
- Bridge Deck Joint Repairs – Granor XJS system for abutments and Sika Emseal BEJS system for piers, using specified nosing and sealant
The Bobbin Head Road Bridge (B476), originally built in 1956, spans 58.5m with three 19.5m prestressed concrete girders. A structural inspection in May 2020 revealed significant deterioration, particularly in the pier headstocks within the tidal zone, where reinforcement corrosion, concrete spalling, and bearing assembly degradation were observed.
Freyssinet was first engaged in 2020 for concrete patch repairs. However, a detailed inspection identified more severe structural issues, leading to a de-rating of the bridge capacity to 16 tonnes GVM and a one-lane traffic restriction. As a result, the initial project scope was revised, leading to a re-tender process. Freyssinet was awarded the second stage of the project in August 2022 to undertake comprehensive rehabilitation works.
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General ContractorFreyssinet Australia Pty Ltd
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Customer/Owner:Sydney Trains
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EngineerHatch (Lindsay Dynan)
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Freyssinet SubsidiaryFreyssinet Australia (NSW)
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Works periodOctober 2022 - April 2023