On Thursday 10 October 2024, the Study Tour visited the North East Link Project in Melbourne as part of the visit to Arcadis. The visit to the North East Link project consisted of two parts. In the first part, a general presentation was given about the contents of the project. In this presentation, further explanations were given about different engineering topics within the project. For the second part, the construction site at the Bulleen Interchange was visited.
One of the key objectives of the North East Link project is to significantly reduce congestion in Melbourne, particularly for heavy vehicle traffic. The 6.5 km tunnels are estimated to divert up to 15,000 trucks from local roads each day. This will ease the pressure on residential areas and improve safety for drivers and pedestrians. Additionally, users will benefit from a projected reduction in travel times by up to 35 minutes, transforming daily transport efficiency across the city.
The completion of the M80 Ring Road will deliver new lanes and incorporate new traffic technology to manage the increasing flow of vehicles. Express lanes will ensure faster access to the North East Link tunnels, further enhancing the mobility of drivers. Simultaneously, the Eastern Freeway upgrades will see the introduction of Melbourne’s first dedicated express lanes supported by advanced traffic management systems aimed at reducing congestion and improving road safety.
The North East Link project focuses strongly on protecting the environment and has taken several steps to reduce its impact. According to Victoria’s Environmental Effects Act 1978, the project had to go through an Environmental Effects Statement (EES) process, which looks at the environmental impact of the whole development. In 2019, the North East Link Project (NELP) released a detailed EES, which included the findings from 18 experts on issues like groundwater, noise pollution, and biodiversity.
A key part of the environmental rules is managing groundwater. Building the tunnels and interchanges could affect groundwater levels, which are important for the health of nearby ecosystems. The rules include strict guidelines for monitoring and controlling changes to groundwater levels during construction. The project also uses innovative drainage systems to reduce any disruptions. Plans are in place to protect water quality, keeping local ecosystems safe from contamination.
The design process for the North East Link project involves many different engineering teams working together. Civil, structural, drainage, and electrical engineers collaborate using 2D and 3D tools to create designs and check their practicality. This teamwork helps make sure the designs meet safety standards and technical needs. Tools like MicroStation and AutoCAD are used to make functional layouts, while 3D software such as OpenRoads and AutoCAD Civil 3D helps create detailed sections, ensuring everything fits with other infrastructure.
The Bulleen interchange site visit gave further insights into the construction techniques for the upgrade of the current Bulleen Interchange. This interchange needs to be upgraded in order to create a new connection to the designed North East Link tunnel. Besides, other improvements are also incorporated in the design of the new Bulleen interchange. These are the construction of a dedicated busway along the Eastern Freeway, the development of a new Park and Ride at the northern side of the interchange and the reallocation of the Koonung Creek.
The new connection to the North East tunnel is created with the construction of new highway ramps at the Bulleen interchange. Therefore, concrete piles need to be driven into the subsoil with concrete crossheads need to be constructed. These concrete piles with a crosshead serve as the foundation for the bridge sections are positioned on top. The concrete piles are constructed utilizing an efficient technique, which enables the installation of seven piles to a depth of 33 meters in the subsoil, whereas conventional methods typically permit the installation of only two piles to a depth of 25 meters in the same timespan. Additionally, an innovative heating and cooling system is implemented for the curing of the concrete piles above ground level. This system makes it possible to constantly have the ideal curing temperature for concrete. This allows the demoulding of the cast after 48 hours instead of seven days. This heating and cooling system in the concrete piles can also be seen in Figure 1. The system consists of blue hoses in between the steel reinforcement.
The construction of the new connection at Bulleen interchange is subject to significant time constraints. The new highway ramps connected to the North East tunnel need to be delivered on time to the project team of the North East tunnel. Deviation from the construction schedule may result in substantial delays in the overall construction of the project. A critical moment in this project is the assembly of the heavy-lift crane. This heavy-lift crane is necessary to lift the large bridge sections into place on top of the concrete crossheads. The location for the heavy-lift crane has limited clearance. The construction location of the crane needs to be created to within 20 centimetre accuracy. Otherwise, the lift operation of the bridge sections cannot be conducted. This would result in a necessary reassembly of the heavy-lift crane, which would cause a large deviation from the construction schedule.
The Bulleen Interchange is close to important waterways like Koonung Creek and the Yarra River, creating challenges in managing stormwater. The project includes measures to handle runoff from the freeway and nearby areas, stopping pollutants like litter and harmful chemicals from entering the water. Bio-retention basins, sediment traps, and wetlands are designed to clean this water before it flows into natural waterways.
The project also prepares for hazardous material spills from vehicles. Underground tanks and containment systems are in place to handle accidents, ensuring spills are captured and treated without harming the environment. The team also needs to carefully realign Koonung Creek, keeping its water flow intact while building new channels that meet both engineering and environmental standards.