Piling, shoring and ground anchoringspecialist Civil Foundations has utilisedOneSteel Reinforcing’s 500PLUS 32mmREIDBAR as a grout injected groundanchor, in its first sheet pilingapplication in Australia.

Civil Foundations was responsible for thesheet piling of the three level basementcar park for The Pinnacle, a new block ofresidential units being built by Sydney-based property developer Skyton.

Located at 151 O’Riordan Street inMascot, the project presented an extreme

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dewatering and shoring challenge forCivil Foundations, with a perched watertable and a 100 year old sewer servicingmore than 50,000 local homes runningadjacent to the site.

Civil Foundations installed 12mm thicksteel sacrificial sheet piling to a depth of15m around the perimeter of the site tofacilitate excavation and site works, untilthe basement car park slabs were inplace.

The 750mm wide AU14 sheet pilesoverlap and interlock with each other and

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500PLUS REIDBAR helpsshore up difficult site

® 500PLUS PREFAB & 500PLUS REIDBARare Registered Trade Marks used by OneSteel.

500PLUS REIDBAR

500PLUS REIDBAR is acontinuously threaded, steelreinforcing bar and couplersystem, which can be cut andjoined at any point, greatlyimproving steelfixing flexibility.

The rugged threads areresistant to damage and permitrapid coupling on site.

500PLUS REIDBAR is availablein most rebar diameters: 12,16, 20, 25 & 32mm, with anextensive range of couplersand construction accessoriessuch as nuts, threaded inserts,foot plates, grout sleeves andnailing plates, enabling the500PLUS REIDBAR system tobe used in a wide variety ofapplications.

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were retained by a series of 12m long,32mm diameter, continuously screwed500PLUS REIDBAR grout injected groundanchors at 1.5m centres.

Civil Foundations Principal, Tony Derham,said the project was the most challenginghis company has been involved in.

“The water table was only a couple ofmetres below ground level and theground conditions around the site were amix of soft silt, sand and clay.

“The hydrostatic pressure on the sheetpiles was so high, you could see the steelsheets were working hard between theground anchors in some locations. And,because the hydrostatic pressure was sohigh, water would spray out at very highspeed from even the smallest of holes, soefficient dewatering while installing theground anchors was an absolutenecessity,” he said.

Installing the 12m long 500PLUSREIDBAR anchors required a speciallymodified auger, explained Tony Derham.

“To be able to drill to a depth of 12mrequired the use of some very highstrength steel tube, normally only used inoil and gas exploration.

“We also custom made the drilling headfrom high strength plate steel,” he said.

Once in place, the 12m lengths of500PLUS REIDBAR were grouted and alarge square steel base plate was securedinto position by REIDBAR sphericalwashers and nuts, with the nuts tightenedto around 350 Kn.

The edges of steel base plates were thensealed with bentonite, then welded to thesheet piles to provide a watertight seal.

“With the site located in what washistorically an industrial area, the groundwater contained a number ofcontaminants, which meant we had toinstall a filtration system to clean thewater up before returning it to theground,” said Mr Derham.

The dewatering system comprised 6 metrewell points connected to a 150mm headerpipe around the perimeter.

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Mr Derham explained: “The pump wechose was a BBA MP60 vacuumdiaphragm pump. The pumps wereconnected by remote control and alertedus if the power or vacuum dropped, sowe could react instantly. The flow ratewas typically around six litres a second.”

Civil Foundations used its new ABI 12/15and Bauer RTG19T rig to install the 15mdeep sheet piles.

The first of its type in Sydney, the rigworks by using a telescopic mast with anarrow style of vibro hammer under highfrequency. The new RTG is the mostpowerful unit imported by CivilFoundations into Australia and is capableof installing 19 metre sheet piles.Powered by a CAT C18 650HP engine,the unit also runs a rotary drive capableof installing CFA piles up to 750mmdiameter to a depth of 20 metres.

Civil Foundations next project will see therig being used in totally different groundconditions and in another challengingapplication.

“Our next job at Zetland will be on muchfirmer ground conditions, and will beinnovative in that the sheet piles willactually form the internal wall of thebasement levels. This approach, in whichthe sheet piles are given an applied finishto improve their appearance afterinstallation, is very common in Europe,”said Mr Derham.

“With the current growth in apartmentconstruction, we expect this approach willbecome more commonplace in Australiaover the next few years, as it offerssignificant economies compared to thecost of building a false wall in front of thesheet piles,” he said.

“We’ve worked with OneSteel Reinforcingon a number of projects and their servicehas been excellent. A couple of times weran short of materials and it could havedelayed the project, however, OneSteelReinforcing pulled out all the stops tomake sure we got the materials when weneeded them.”

500PLUS REIDBAR is a hot-rolled,continuously threaded, steel reinforcing

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® 500PLUS PREFAB & 500PLUS REIDBARare Registered Trade Marks used by OneSteel.

CONTACTS

New South WalesTel: 02 9794 1000Fax: 02 9772 1689Western Australia

Tel: 08 6332 3111Fax: 08 6332 3179

VictoriaTel: 03 9207 2200Fax: 03 9207 2270Northern Territory

Tel: 08 8947 0330Fax: 08 8947 0358

QueenslandTel: 07 3845 5655Fax: 07 3845 5697

TasmaniaTel: 03 6273 0300Fax: 03 6273 0315South Australia

Tel: 08 8349 8666Fax: 08 8349 7555

ACTTel: 02 6260 1244Fax: 02 6260 1286

www.reinforcing.com

bar and coupler system, which can be cutand joined at any point, greatlyimproving steelfixing flexibility.

The rugged threads are resistant todamage and permit rapid coupling on site.

500PLUS REIDBAR is available in mostrebar diameters and offers an extensiverange of couplers and accessories making

it suitable for a wide variety ofconstruction applications including:

• Staged construction

• All wall, column, beam and slabconnections

• Starter bars and penetrations

• Tilt-up/precast concrete

• Ground stabilisation applications.