Menard completes ground improvements supporting new Batemans Bay Bridge

20 July 2020

A better bridge connection across popular Batemans Bay in New South Wales, expected to bring economic and social benefits to the region, is another step closer to completion thanks to specialist ground improvement technology from Menard Oceania.

Menard has used Controlled Modulus Columns (CMCs) to support the new $274 million NSW Government funded four lane bridge across the busy Clyde River. Menard first developed its CMCs technique in the 1990s to support foundation work on soils with low weight bearing capacity and high deformation. Since then it has completed 2,500 projects using the technique including the Brisbane International Cruise Terminal and Perth’s Optus Stadium.

A CMC is essentially a small diameter displacement auger which is pushed into the soil matrix by a modified piling rig, in this case, a Casagrande B250. Once the tool has completely penetrated through the compressible soils, the auger is extracted, and concrete or mortar is pumped under pressure through the hollow stem to fill the anulus left by the operation. The CMC is then replicated on a grid pattern. The matrix of columns ultimately controls the stiffness or modulus (an elastic soil parameter and a measure of soil stiffness) of the soil, hence the name ‘Controlled Modulus Column’.

CMCs will support transport for NSW’s new southern approach to the Batemans Bay Bridge replacement as it continues to be built, eventually replacing an old vertical steel lift truss structure built in 1956 which rises twice daily to let vessels pass under it. CMCs will ensure a smooth transition from the uncontrolled embankments into the rigid bridge abutments founded on piles.

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Menard was awarded the contract for the treatment of soft soils around the significant 3,500 square metre project site last year by design and construct contractor John Holland. Menard started work at the site in September and has now completed the foundation element of the project.

Kevin Doyle, a civil engineer and Menard’s project manager, says a five-man team drew on the company’s 20 years of experience when installing CMCs to support the new bridge development.

“The first step of a ground improvement project was undertaking soil testing, and then navigating the design process to integrate our solution with the proposed structure. The design process can be lengthy, and on this occasion, we finished the last CMC one year to the day since starting. Once the design was completed, we started construction of the CMCs. We were on site for over two months, which sounds a lot for one bridge approach, however the biggest challenge on this project was the depth requirement combined with the complex interbedded alluvial soil deposits. Since inventing this technique some 20 years ago, Menard initially installed CMCs to depths in the order of more than 20 metres. However recently Menard has achieved depths internationally of over 50 metres. For this project however we went to over 30 metres to get to good soil.”

Mr Doyle says the successful and safe installation of CMCs was high on his team’s agenda throughout the project, coupled with robust investigation of potential environmental impacts.

“It’s an environmentally sensitive project within a marine park, and internationally listed wetlands with mangroves only metres from the project site. We needed to make sure no effluent from our works went into the river and carefully managed our materials on site so there were no spills. Detailed environmental considerations went into our foundation work due to the unique ecology of the area which also includes substantial natural oyster beds. I’m pleased to say there were no environmental issues as a result.”

Mr Doyle, who has been with Menard for eight years since arriving in Australia from his native Ireland, has worked on many significant projects over this time but says the Batemans Bay Bridge replacement project has easily been one of the best yet.

“Our team worked very closely with, and for, John Holland. The company had an excellent team to work with and we worked well together from the design and execution phase to delivering our works on budget and ahead of time. It’s great to see the job has been done well and know that the client is equally as happy as we are.”

John Holland Construction Manager Ed McPhillips says Menard’s scope of work, and location for this activity was extremely challenging.

“The key for us was to engage a professional organisation who understood and would manage the constraints with working in close proximity to a pristine environment and live highway traffic. We needed an organisation that could guarantee the safety of their people, the community and other nearby subcontractor personnel, and could come on the journey with us to provide solutions for a highly complex design and construct process, “ Mr McPhillips says. “Menard achieved all of this, and more. John Holland could not be more pleased with the result.”  

Once the new four-lane bridge is complete, the local community will benefit from less congestion in and around Batemans Bay. A height clearance of 12 metres will also allow vessels to travel along the Clyde River unimpeded while a three-metre shared path will make it accessible to pedestrians and cyclists.

 

--ENDS--

 

Source:  Menard Oceania - www.menardoceania.com.au

Date of Original:  16 July 2020

Contact:  N/A

External Links: 

https://www.rms.nsw.gov.au/projects/batemans-bay-bridge/index.html

https://www.johnholland.com.au/ 

Recent news by:  Menard Oceania

 

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