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Project: Freeflow – Central Motorway Junction Stage One


Year:2003 – 2004

Alliance:Transit, Fletcher, BCHF, Higgins





Supervision of labour and plant for the widening and upgrade of the section of southern motorway between Gillies Ave and Grafton Bridge. The widening works resulted in two new lanes on New Zealand’s busiest stretch of motorway where there are over 200,000 vehicles passing through the area each day. Works have included:


  • Retaining wall construction to foundations and insitu barriers

  • Installation of 3000 linear metres of precast barriers

  • Installation of 1500 linear metres of slip-formed median barrier

  • Widening of vertical basalt wall through the use of rock breaking and excavation

  • The wall required support with rock anchors and 2000m² of reinforced shotcrete

  • Excavation methods using rock breaking and PCF explosives

  • Construction and installation of 15 precast stormwater quality improvement devices (SQID’s), each 7m long x 2m deep x 0.800m wide

  • Completion of the new 2km stormwater drainage system upgrade which included 12 newly formed soak holes, precast pipes and channels

  • Widening of the existing motorway bridge involving abutment widening, beam installation and insitu deck to tie into the existing bridge deck

  • Construction of 12 insitu gantry foundations including rock anchor installation and excavations

  • Installation of six new sign gantries

  • Construction of pier protection under Mountain Road bridge poured insitu over a 50m span

  • Ten new service ducts installed to match the new alignment over 3km

  • Construction of new lightpole foundations and installation of poles

  • Works had to be carried out without impacting traffic flow by closing the shoulder with temporary barriers and working within this narrow corridor. While the project has taken two years to complete, 18 months of this time was spent on a 24-hour rotation, seven days a week

  • Significant inputs into alternative work methodologies for night works were developed to reduce noise and minimise potential impacts on the surrounding neighbourhood. This was the first section of motorway upgrades that had such a significant noise profile

  • New and alternative methodologies for controlling site runoff were also developed. Work areas were not suitable for traditional controls and were surrounded by live lanes with barriers as the only delineation

  • There have been no LTI’s under the management of this contract

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David Pratt - Director

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