McElligotts was engaged by Melbourne Water to rehabilitate the Wantirna Sewer Shaft in March, 2017.
The scope of work included the rehabilitation of a 65m deep and 12m diameter sewer shaft. At McElligotts, the safety of our staff and clients is our top priority, so It was especially important for us to maintain a safe system of working as working within a live sewer can be dangerous for a number of reasons.
Our work on this project included:
Access, egress and rescue capability
Work platforms, safety lines and catch facilities
Cleaning of all internal surfaces in the shaft
Removal of all softened and acidified concrete from shaft walls and platforms
Rehabilitation and remediation of all concrete surfaces including rebuiliding
Application of a protective coating
McElligotts finished this project within a short six-month time frame, working around the clock to ensure the Wantira Sewer Shaft was restored as quickly as possible.
McElligotts was engaged to remediate concrete seepage at the Black Hill Water Reservoir. Owned by the Hunter Water Corporation, the Black Hill Water Reservoir is an 86 million litre water reservoir, constructed in 1939. The structure was still in good overall condition, but had begun to show signs of seepage, with water escaping through deteriorated joint seals and cracks in the concrete slabs. Remedial concrete works were necessary to keep the water safe and the structure stable and protected. We completed the project between July and September 2017.
The project demanded a 20-year minimum design life and certification with the Australian standard AS/NZS 4020 for contact with potable water.Firstly, we applied a primer to the concrete surface and placed a flexible bonding tape to the 5,000 lineal metres of joints. To repair the cracks in the floor and toe slabs, Intercrete 4841 (cementitious-polymer protective coating) and Intercrete 4872 (waterproof reinforcing tape) were selected as the most suitable products within the project’s requirements.
We had a timeframe of 42 days for this project which had a floor area of 11,000m2 and short shutdown windows when we were able to apply the coating. When selecting the coating and application method, we needed to accommodate for the structural movement and stresses observed during the regular usage and maintenance of the site (up to 5mm vertical movement in the floor was observed in prior surveys).
Ultimately, we were able to meet the client’s requirements to schedule, and we’re pleased with the finished outcome. The Black Hill Water Reservoir will be well-protected from any structural stress and corrosion for decades to come.
Built in 1978, Westgate Bridge is an iconic structure that’s played a huge part in moving Melbourne for decades. After thirty years of operation, Westgate Bridge had daily traffic of 160,000 vehicles, compared to the 40,000 it was carrying per day after opening. McElligotts was sub-contracted by John Holland Construction for abrasive blasting and other remedial works.
Roles we performed included removing and containing red lead paint, abrasive blasting of the internal and external structures and creating profiles for strengthening steel and carbon fibre to be attached. At the time, this was one of the largest projects in the world incorporating carbon fibre. We enjoyed working on this project and overcoming the challenges it faced, including traffic and fast turnover requirements. At the height of this project, McElligotts had 100 workers per day on-site.
Westgate Bridge 2019-2021:
In February 2019, we were proud to have again been contracted by VicRoads to work on the Westgate Bridge, this time as part of their painting refurbishment project. We are still currently working on this project and hope to have it completed by January 2021 in conjunction with the set deadline. The scope of work is somewhat similar to the original work we did on the bridge, only this time we are just focusing on restoring the painting and abrasive blasting rather than strengthening.
Our main task is to abrasive blast and paint 55,000 sqm of steel on the underside of the bridge, which included blasting the 9 platforms that are suspended 60m off the ground. In order to do this, the platforms are contained to a class 1 containment system and then abrasive blasted back to bare steel for inspection of the steel condition. In alignment with our sustainable values here at McElligotts, all waste material is vacuumed up and bagged at the bottom of the bridge. After this, the surface is then re-blasted and a 4-coat system is applied to the steel structure and signed off before the platforms can be traversed along the bridge.
McElligotts performed remedial construction works during the Eastern Treatment Plant refurbishment between August 2011 and November 2013. During construction, major leaks had developed in concrete structures, requiring a strip of the existing coating and a relining. Our team lined over 5000m2 of concrete with Polibrid, using a reinforced coating system we’d developed using geo fabric. Geo fabric was pinned to the concrete to mitigate the potential for future coating failures.
From there, we applied intercrete bands to expansion joints, providing extra strength in the coating system to prevent water pressure leaking through the joints. Ultra-high pressure surface preparation was performed on the external concrete surfaces to ensure the correct surface profile was achieved. As the water treatment plant has some high foot traffic areas, we made sure that the coating selected was non-slip. This was a large project requiring many co-ordinated steps with 200 other contractors onsite working alongside us.
We conduct remedial maintenance programs at oil and gas refineries across Australia, putting together maintenance programs tailored to our client’s needs. Our team have worked on tanks, pipelines, walkways, vessels and exchangers, providing services that include:
Ultra-high pressure cleaning and surface preparation
Abrasive blasting and hand tool surface preparation