Waikato Expressway-Ngaruawahia Section Stage 2
Fletcher Construction were the main contractor to NZTA for this project, with Higgins as their specialist pavement subcontractor.
The project was a section of the Waikato Expressway strategic corridor - a Road of National Significance. The new 7km of new dual lane expressway crosses mostly farmland and low lying areas between Horotiu and Taupiri north of Hamilton. This allows SH1 traffic to bypass the Ngaruawahia township, reducing congestion and travel time and improving safety for the journey between Hamilton and Auckland. This 'design and construct contract' comprised 220,000m2 of pavement area, over 200,000t of aggregate, seven bridges (including an impressive single span crossing of the Waikato River), two structural asphalt roundabouts, and tie-ins and changes to local roads
Higgins constructed and surfaced all of the pavements for Fletcher Construction. A project team was set-up to complete the work, utilising resource from Higgins Waikato, supplemented with Higgins teams from the Bay of Plenty, Hawkes Bay and Auckland. Up to five construction and paving crews were working on site at any one time. Higgins Engineers were embedded in the main project delivery team, to plan, manage and implement the pavement work to ensure quality, safety, environmental and production requirements were met. Assistance was also provided to the design team by Higgins Group technical specialists. The ability for Higgins to sample, test and analyse materials in-house enabling the project designers to make quick decisions on subgrade treatments.
SITE SAFETY & TRAFFIC MANAGEMENT
Work on the heavily trafficked local roads and State Highway tie-ins required a high level of planning and concentrated effort. Traffic switches on Lake Road and SH1B involved night-works as well as working in a live traffic environment. Higgins carried out the “online” construction works in accordance with the programme and approved TMP (which we helped develop) to minimise effects on the public and stakeholders. Site Safety was set and maintained at a very high level for the project with comprehensive task analysis, hazard identification, management plans and reporting required to interface with the Fletcher System.
This high profile site was subject to weekly audits by EW. Higgins teams were critical in allowing progress to continue through winter, working with Fletchers to establish and maintain controls, stabilise vast areas of subgrade and earthworks areas, and ensure no dirty water left the confines of the site due to the pavement operations.
Higgins carried out over 10,000m3 of cut to fill and cut to waste from the subgrade preparation works using motor scrapers and excavator/truck combinations. Final topsoil placement and trimming of over 40,000m2 of grassed median was also undertaken. Over 150,000m2 of subgrade was lime and/or cement stabilised with Higgins specialist Wirtgen equipment.
CONSTRUCTION: PAVEMENT AND SURFACING
This design and construct contract comprises 220,000m2 of sealed pavement area, over 250,000t of aggregate, seven bridges (including the single span crossing of the Waikato River), two structural asphalt roundabouts, and tie-ins and changes to local roads. A section of HiLab pavement was also constructed and extensively tested in an area of the alignment selected by NZTA. All main alignment basecourse was cement stabilised, tested and prime coated prior to the first coat seal which was applied over a 5 day period. At Higgins recommendation the chipseal was changed from a 2 coat to a racked-in with supplementary truck trafficking to allow an opening speed higher than a 30 or 50km/h business as usual TSL. A section of High PSV chipseal was also constructed at the northern end of the project.
Higgins undertook over 22km of subsoil drainage and minor drainage structure installation.
BRIDGES AND OTHER STRUCTURES
Bridges required pre-levelling and SMA or OGPA surfacing. This required detailed design and testing of the asphalt mixes to ensure ride, integrity and waterproofness all met the required standard. Higgins also carried out preparation for concrete kerbs and barriers, and reinstated finished surfaces where required.
The project was completed on time for the community open days and officially opening in December 2013.