Enterprising Approaches in the Successful Construction of a Toll Motorway (East Link) Through Suburban Melbourne, Australia

    Ken Mathers Ken Mathers, Chief Executive Officer, Linking Melbourne Authority, Australia   Arun Kumar, Professor of Infrastructure Management Queensland University of Technology, Brisbane, Australia Arun Kumar

    Overview

    A 39 kilometer toll motorway was constructed on budget (A$2.5 billion) and five months ahead of time. It was opened in June 2008. This project involved 17 interchanges, 88 bridges and twin three lane, 1.6 km tunnels. It has three lanes in each direction for 33 km and two lanes in each direction for 6 km. EastLink connects the eastern suburbs of Melbourne and was delivered under a Public Private Partnership (PPP) arrangement by Connect East (listed on the Australian Stock Exchange) for the Victorian Government agency, Southern and Eastern Integrated Transport Authority (SEITA). Project development was undertaken by two of Australia’s largest contracting organisations, Thiess and John Holland, in a joint venture arrangement.

    This paper describes the uniqueness of the project, construction practices and the working relationship with owners and contractors that led to a successful outcome. This project has set new standards in design, construction speed, safety, environmental impact, community engagement and significantly enhanced the urban amenity of the corridor.

    Background

    EastLink Motorway
    Figure 1: EastLink Motorway overview
    The road reserve for this corridor was planned in the early 1960’s. Environmental impact statements were developed and consulted with the community living along the corridor in the 1990’s. As Melbourne continued to expand, the construction of the Motorway became imperative. Work commenced in March 2005 and was completed in June 2008. An overview of the motorway section is being presented in Figure 1.

    Performance Based Specifications

    Right at the tendering stage, considerable thought was given to encourage competition in the private sector to achieve the best outcome for the Motorway. One of the key elements was devising the performance based specifications that would make it clear what was needed without specifying how it should be achieved. Interestingly, the document produced was a fraction of the size of a normal specification, yet spelt out the State’s requirements. It had set targets such as a 100 year design life for structures.

    The specifications provided for the road to fall within a certain route envelope but the exact alignment was variable; the shape of the interchanges was open to variation, and the pavement had to perform to a certain standard yet its make-up was not prescribed. Urban design had to be a part of the mix and the bids had to show that they reflected community expectations along the route. The requirement of the tolling system was that it had to be fully electronic and it had to be interoperable with other electronic toll roads in Australia. Toll levels were not prescribed with the only requirement deemed that escalation had to match movements in the Consumer Price Index (CPI) with changes being applied annually. Both design and construct contracts were self-monitored by Quality Assurance (QA) procedures and checks as work progressed.

    The Independent Reviewer

    The Independent Reviewer (IR) was appointed jointly by the Government and the Concessionaire. The IR’s role involved a general overview and reasonable checking in order to be satisfied that the various detailed checks and monitoring processes were carried out correctly and, in order to ensure compliance with the design construction requirements. This organisation reported jointly to the two employers, ensuring impartiality between the two client sides. All design and construction information developed by the contractor had to be provided to the IR who had the responsibility to certify completion before the road could be opened.

    Working Arrangements

    For the processes to be efficient, tight timelines for making comments were agreed by all parties to ensure the contractor was not unduly held up waiting for responses. This arrangement was successful as effective working relationships and flexibility were established between the people working on the project (the contractor and the two client bodies). An electronic tracking system was implemented and improved the efficiency of the documentation flow.

    Another efficient process implemented was that construction itself was subjected to Quality Assurance (QA) processes. The contractor was responsible for auditing and guaranteeing its own systems according to appropriate QA standards.

    The Construction Challenge

    rotating pick-axes
    Figure 2: The road headers carving the rock away with multi-toothed rotating pick-axes
    The Tunnel: The construction of the $600 million twin tunnels was a complex operation. The diameters of each tunnel exceeded 16 meters with special ventilation buildings at the exits. These buildings incorporated large fans to capture the air leaving the tunnel and the car exhaust contained in it. The excavation was undertaken by four large machines known as road headers. These have a rotating head with cutting teeth at the end of a pivoting boom for cutting away the material at the heading of the tunnels, Figure 2.

    The tunnel was also fully “tanked.” This means that it was made watertight, rather than allowing water to trickle in the tunnel and then draining it out. This was done by having a circular cross section for the tunnel and using a drainage blanket and waterproof lining, Figure 3. An overview of the tunnel is presented in Figure 4.

    Full tanking
    Figure 3: Full tanking (waterproofing) with a membrane

    The Bridges: For most of the 88 bridges, pre-cast reinforced concrete units were used for speed, quality and economy. In the case of an operational railway line which overpassed the new road, the construction schedule was planned in such a way that it was closed only for a very short time. This was achieved by first, installing the foundations and final columns of the new bridge and then the crosshead supports for the bridge super structure.
    Tunnel overview
    Figure 4: Tunnel overview
    The foundations of the four-span bridge comprised 1.8 metre diameter bored concrete piles which could be installed outside the train “envelope,” Pairs of the piles at each of three pier positions and for the abutments were put in through the existing rail embankment. They went into the ground as support but stood free in the top few metres once the ground was excavated around them, forming the columns of the bridge. The super structures, complete with new rail tracks for the new railway overpass, was built alongside the operational railway on the extensions of the crossheads. Times for completion is simultaneously with the bridge structure. The super structure was slid in after a weekend so that the railway was ready for the peak rail operation at the beginning of the working week.

    constructed bridges over the motorway
    Figure 5: Newly constructed bridges over the motorway
    A 500 tonne mobile crane was used for lifting heavy crossheads and beams for bridge construction throughout the project. Some of the bridges including the rail bridge over the motorway are shown in Figure 5.

    Use of precast segments for construction: The contractor decided to establish a special precasting yard for the manufacture of pre-cast reinforced concrete elements. During the two year operation, the yard produced over 23,000 pre-cast units, of a wide variety from bridge beams and parapet panels to assorted noise wall panels, retaining wall fascia units and bridge pier sections. This ensured tight quality control of all structural elements and other pre-cast products and achieved a better result than that normally achieved by onsite casting. Most of the bridge beams were Super Tee Beams, a V-shaped trough with a flat base and flat projections at the top. The special design was developed in Australia and is now widely used on major road projects. A key advantage of the design is that it can be produced in various depths for different span lengths. The tolling system: A multi-lane free-flow Electronic Toll Collection (ETC) system was used. The recognition by vehicles is automatic through electronic tags mounted inside the vehicle which are not required to slow down or stop as they pass under the toll gantries. This electronic tag complies to agreed standards and can be used throughout Australia on all other toll roads. Along its 39 km length EastLink has 13 tolling points each with two gantries (Figure 6). This tolling system has the ability to handle 4.5 million vehicle passages (transactions) per day. The twin gantries also enable vehicle detection systems to record registration plate details should vehicles not be equipped with the electronic tag. Video tolling is also possible.

    electronic tolling system   coloured noise wall
    Figure 6: Free flow electronic tolling system   Figure 7: Typical coloured noise wall

    Noise walls: Over 13,000 noise wall panels were installed. The sections of noise walls were different in shape and colour to improve the visual appearance and better integrate with the surrounding environment and look as natural as possible. Typical wall panels, including transparent sections, as shown at Figures 7 and 8 were manufactured precast at the precast fabrication yard.

    Motorway
    Figure 8: A typical noise wall along the Motorway
    Road construction: The construction work involved three lanes in each direction for 33 km, two lanes in each direction for 6 km. This involved over 7 million cubic metres of earthworks, 1.1 million tones of asphaltic concrete, and 380,000 cubic metres of concrete. Asphalt laying was a highly coordinated large scale logistics exercise in its own right during construction (Figure 9).

    Concluding Remarks

    EastLink has proven to be one of the most successful toll road projects in Australia delivered as a Public Private Partnership. Thirty months after opening, traffic growth is continuing at an incredible 10% per annum and neighbouring communities are praise worthy of the delivered outcomes.

    Asphaltic concrete laying
    Figure 9: Asphaltic concrete laying
    Key success factors included clarity in contractual documentation and understanding of the roles of respective parties, early establishment of organisational structures, the rapid recruitment and training of human resources, establishment of a project specific pre-casting yard, bridge construction using standardised pre-cast elements to the maximum extent possible, establishment and retention of highly effective working relationships between the project parties, continuous community engagement and the early resolution of construction issues, as well as environmental enhancements and the provision of urban amenity outcomes throughout the corridor.

    Reference

    EastLink: Melbourne’s Motorway Masterpiece, Connect East SEITA

    NBMCW March 2011

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