Jet grouting to start

getimage555Thousands of tonnes of concrete are being injected into the Christchurch Town Hall’s foundations as part of a multi million dollar project to strengthen the building.

This week contractors began the lengthy process of jet grouting the quakedamaged building’s foundations. They are using three grout machines that have been imported from Germany for the work, during which more than 1000 large concrete piles will be injected eight metres into the ground.

In the February 2011 earthquake the land beneath and around the Town Hall was severely damaged. Although the building itself fared relatively well, significant strengthening of its foundations is needed. Jet grouting has been identified as the most effective repair solution to address the land issues underneath the building.

‘‘Grout and water is injected into the ground at high velocity to create columns of soilcrete, which is soil cemented with grout. The columns will overlap and interlock to create an earthquake resistant underground wall of columns that will protect the building from soil movements,’’ said Project Manager Paul Youngman.

A total of 27,000 cubic metres of jet-grout concrete – which would fill 270 average family swimming pools, 37,500 bath tubs or 200 buses – will be used during the process.

A thick concrete slab will be laid over the concrete columns once the jet-grout work is complete, which will help to bring the Town Hall up to 100 per cent of New Building Standard.

Contractors have spent five months preparing the site for the jet-grouting work, which is expected to be completed in June next year. It is the first stage in the $127.5 million repair of the Town Hall.

Christchurch City Council anchor projects unit manager Liam Nolan said the restoration work would ensure the Town Hall could continue to be enjoyed by Christchurch residents for the next 50 years and beyond.

‘‘The Town Hall is one of the city’s most treasured civic and heritage buildings and this restoration work will ensure it is better and stronger than it was pre-earthquake. Starting on the Town Hall foundations marks the culmination of four years of work. This has included engineering assessments, going through a tender process and appointing a contractor to undertake the restoration work,’’ Nolan said.

‘‘By the time we’ve finished work on foundations, the ground underneath the building will be significantly stabilised, ensuring we can get on with the rest of the work needed to restore this building to a world-class facility that can be used for many years to come.’’ .

The restoration of the Town Hall, which also includes a significant upgrade and refurbishment of the facility, is due to be completed in 2018.

Source:

  • Lois Cairns
  • The Press
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Concrete, concrete and more concrete!

1436745206333A construction firm has performed the largest single concrete pour of Canterbury’s rebuild to date.

Leighs Construction workers started the massive task at 1am on Saturday and worked until late afternoon, with about 1870m3 of concrete pouring into a Christchurch central city construction site’s basement.

The pour laid the foundation for the new ANZ Centre on the site of the former Triangle Centre, bordering High, Cashel and Colombo Streets.

About 370 trucks delivered the concrete.

Leighs Construction’s managing director Anthony Leighs said this was a massive milestone for the CBD rebuild as a whole.

The team craned a pump into the basement and pumped the concrete into the area from three points on High St, Cashel St and Colombo St, he said.

The next stage of the project would involve construction of the basement walls and columns, with a tower crane due on site at the end of the month.

The new four level building would include ground floor retail and hospitality areas of 1700m2 and three levels of office.

Source:

  • The Press
  • Photo: Dean Kozanic

Concrete pour sets the standard

pour

The largest concrete pour within the central city cordon took place in Christchurch yesterday…

For more, follow the link below;

http://www.christchurchrebuild.co.nz/?p=889

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