Creating a tunnel that connects the largest metropolis in New Zealand is no easy task. The logistics alone require an incredible amount of forethought and planning, and many would shy away from such a commitment. However, Link Alliance, an international consortium based in New Zealand met the challenge head-on and is succeeding thanks to their use of advanced design technology.
The City Rail Link is beyond ambitious. Designed to connect the Auckland region by creating twin 2.14 mile (3.45 kilometer) long rail tunnels directly under the city. Designed to transform the rail systems from an end-to-end station into a through-line. The project will service the 1.7 million people in the city and help to bring an end to the city’s infamous traffic congestion.
Working around the distinctive geographic layout and existing infrastructure of Auckland, along with the tremendous amount of inhabitants, created unique issues in the project. Utilizing BIM and other digital design solutions, the Link Alliance team was equipped with the technology needed to plan around any geographic obstacle and minimize the disruption to the people that call the city home.
The innovative use of technology to overcome challenges led to the City Rail Link project winning an AEC Excellence award from Autodesk. The GovDesignHub editorial team reached out to Link Alliance to learn more about this award-winning project and the role that digital design solutions played in facilitating the planning and construction.
GovDesignHub (GDH): Tell us a bit about the City Rail Link. Why is this project important? What are the benefits to the Auckland region?
Link Alliance: The City Rail Link (CRL) is the largest transport infrastructure project undertaken in New Zealand, costing NZ$4.4 billion (US$3.16 billion). Construction began in 2016 and will be completed in 2024.
The project will transform the city’s main rail terminus, called Britomart, from a dead-end station to a through-station connecting with an existing suburban station, called Mt Eden. In addition, two new central city underground stations are being built on the CRL route.
Auckland’s population is around 1.7 million (NZ population is 5 million) and is expected to exceed 2 million in a few years which will create congestion and become a major issue. Previously the city has focused on cars and motorways but there has been a big shift in spending – and passenger numbers – to public transport.
CRL is designed to transform Auckland’s rail services and the wider public transport network that also includes buses and ferries. There will be more trains in and out of the city which is a major economic hub. Trains will also be longer – nine carriages instead of the current six maximum – and significant travel time savings.
During morning and afternoon peaks, CRL will move the equivalent of 16 extra traffic lanes which will reduce road congestion by providing commuters with a viable alternative to their car, and bus congestion in the city center will also be reduced.
“The Link Alliance has embraced a digital model-based and data-driven design development approach with high standards. Through working in a unified common data environment, the alliance has streamlined the development of design visualization material for peer and stakeholders reviews, public consultations, and communications.”
Innovation is a feature of CRL. In addition to the AEC Excellence award, the Project has also won international recognition for the concept designs of its new stations – CRL has worked with Māori communities in Auckland to produce designs that reflect the city’s cultural past as well as its future. It has also won praise for engineering innovation after safely raising and then lowering the city’s heritage-listed Chief Post Office which now forms part of the Britomart Station so that the CRL tunnels could be built under it.
CRL leads the way in BIM and Digital Engineering. With its integration, a requirement of the project delivery, the Link Alliance has dedicated significant resources for the setup and implementation of the practice to assist in the delivery of the new stations, tunnels, and civil works. Although not as visible as the heavy construction work required, the integration of the digital environment enables better and more agile delivery of the work on-site – benefiting the Auckland region in unseen but invaluable ways.
GDH: What different digital design solutions were utilized in the planning and design of the project? Did advanced BIM solutions play a role in expediting the initial planning and community approval processes?
Link Alliance: The Link Alliance has embraced a digital model-based and data-driven design development approach with high standards. Through working in a unified common data environment, the alliance has streamlined the development of design visualization material for peer and stakeholders reviews, public consultations, and communications.
From the outset, the Link Alliance established ‘tiger teams’, a roundtable discussion with colleagues from varying disciplines to explore, holistically, the design, construction, and maintenance options for the project. BIM and digital engineering solutions enabled the tiger teams to visualize the proposed solutions, reaching consensus quickly and decisively while further driving great outcomes and maintaining momentum.
Concept drawing of proposed Aeotea station entrance, courtesy of City Rail Link.
GDH: What logistical challenges does the construction of the “largest transport infrastructure project ever in New Zealand” create? How is a project like this – a massive infrastructure project in the middle of one of the country’s most populous cities – more challenging and disruptive than other projects? How will advanced BIM and other digital design solutions help to minimize those disruptions?
Link Alliance: Working in a congested urban environment is always a challenge: existing buried utilities, additional survey data required, staged traffic management plans, monitoring neighboring structures.
The digital environment has been a game-changer through enabling us to collect, visualize and analyze these constraints to develop appropriate design and construction methods.
A significant benefit of our digital environment is realized as we bring design data to the worksite and feed as-built conditions back to the office to update design models in real-time. We refer to this as ‘information round-tripping and, without neglecting the significance of our digital feats, can partly attribute this to a close relationship between the Link Alliance’s design, survey, and construction teams.
GDH: Part of this project involves marrying new transportation infrastructure with existing transportation infrastructure. What problems and challenges does this create?
Link Alliance: The benefits of City Rail Link Ltd (the project’s client) combining three large-scale contracts known as C3, C5, and C7 for us means a “Whole-of-Life” approach could be better integrated, with the goal of avoiding the traditional challenges faced by similar projects previously.
“BIM is a crucial coordination tool. Coordination between team members is essential to get a successful outcome. The BIM models are the focal point used every day – an essential tool for coordination and as the project’s single source of truth.”
In terms of Digital Engineering, the integration of Existing Rail Systems requires a similar level of digital requirements for assets of Auckland’s wider rail network. The Link Alliance works hand-in-hand with its client, CRL Ltd, project partners KiwiRail and Auckland Transport – an Auckland Council organization operating the city’s transport services – and with separate contractors to ensure seamless integration
GDH: Large projects such as these have a tendency to change and evolve as needs are identified and as requirements shift. Did that happen with the CRL?
Link Alliance: In large projects, implementing robust processes is key to driving changes and requires management. Once processes are implemented, the use of digital tools, such as generative design, helps the delivery of appropriate solutions. Among others, CRL’s tunnels track alignment design has been delivered using generative and computational design techniques
Further, the level of collaboration to deliver the project has been an absolute step change for the industry. Within that step change, BIM is a crucial coordination tool. Coordination between team members is essential to get a successful outcome. The BIM models are the focal point used every day – an essential tool for coordination and as the project’s single source of truth.
Due to the alliance contractual model, the Link Alliance has been able to implement many innovations including computational design and programming.
Concept drawing of the proposed Britomart Station development courtesy of City Rail Link.
GDH: Were all of the stakeholders in the CRL project digital natives that were comfortable and knowledgeable about BIM solutions? What steps had to be taken to get everyone comfortable and capable of the technology?
Link Alliance: Learning, research, and development is a significant focus that is applied across the project continuously, specifically for BIM solutions and technology. A large portion of the scope of the Digital Engineering/BIM department is the training and upskilling of the wider alliance teams, as well as the project’s supply chain teams.
Training includes software and tools training, as well as custom software development that needs to fit a user’s requirements. The Link Alliance has developed its training materials to suit its needs. This, together with its CRL experience, provides the leverage to deliver more of the large-scale and complex projects into the future
One year into the project, almost 350 staff have been trained on BIM software. Much of that training was performed at project commencement and It is anticipated the training peak is still to be reached before it phases out through construction and handover.
There was a major challenge resourcing CRL globally as many team members based overseas. In addition, a lot of the disciplines particularly in the horizontal infrastructure space, are more used to working in isolated 2D environments. This means the project is initially needed and is continually required to rapidly upskill a lot of people.
Feature image courtesy of City Rail Link.