Client: John Holland
Location: Newcastle Region, New South Wales 2300 (NSW)
Project Type: Infrastructure Rectification – Precision Hydro Demolition of Misaligned Bolt Sets
Silver Raven was engaged by John Holland during critical infrastructure works on the M1 Motorway upgrade in the Newcastle region. The project involved the rectification of multiple incorrectly cast bolt sets embedded within newly poured concrete parapets—components essential to the safe and compliant installation of road safety barriers and bridge infrastructure.
Accurate alignment of these bolt sets was essential. However, several sets were discovered to be misaligned, both in parapets already installed on the bridge and in pre-cast units still located in staging yards. Traditional concrete demolition methods were ruled out due to the risk of overbreak and structural compromise. As a result, Silver Raven was contracted to perform precision hydro demolition to remove the bolt sets without damaging the surrounding concrete.
To achieve this, Silver Raven developed a highly controlled solution using custom-engineered steel stencils and guide plates to define exact cutting boundaries at each bolt location. These stencils ensured consistency and prevented accidental overcutting across all work zones. Using high-pressure water jetting (HPWJ), our technicians carried out vibration-free, non-impact concrete removal around the misaligned bolts. This method allowed for surgical precision while maintaining the integrity of adjacent concrete.
Operators cut approximately 700mm deep to facilitate the re-setting of new bolt assemblies in the correct positions by John Holland crews. Stringent on-site water management protocols were applied to manage slurry and waste, particularly on live bridge structures. All hydro demolition activities were carried out under permit-based access controls and in close coordination with site engineers and supervisors to ensure structural compliance and safe operations.
The result was the successful removal of all incorrectly positioned bolt sets without structural damage or delays. The hydro-demolished cavities were clean, repeatable, and ready for accurate bolt reinstallation. Silver Raven’s methodology eliminated the need for costly parapet replacements, keeping the project on schedule while upholding the highest safety and quality standards.
