Planning, design and construction of the WestConnex urban Motorway scheme The largest road transportation tunnelling project ever undertaken in Australia Sydney Motorway Corporation C.C. MacDonald Abstract: WestConnex is a major urban motorway scheme in Sydney, aimed at relieving the current severe congestion on the city's road network. Over 70% of the total route length of 33 Km will be accommodated in .3 or 4 lane tunnels with significant underground interchange works. WestConnex is the largest road transportation tunnelling project ever undertaken in Australia. The project was first proposed in its current form in 2012. However, in the relatively short time since two of the three major stages (tunnel length 14.5 km) of the project have been tendered, design and construction contracts awarded and construction has been underway since 2016. This paper will briefly describe the background that has led to the need for this scheme and then describe the planning, and preliminary design that led to the award of these first two major tunnel construction contracts that have a combined value of approximately AUD$ 9 Billion. The paper also contains some details of the development of the third and final stage of the scheme consisting of two major tunnel construction contacts), which will complete this ambitious AUD$7 7 Billion) scheme by 2013, just over ten years from its conception. The author has had a detailed, client side, involvement in the development of this ambitious scheme from its inception to the current time. Keywords: Tunnelling, Planning, Construction, Client side 1. INTRODUCTION WestConnex is a major investment in Sydney's road infrastructure by the New South Wales (NSW) and Australian Federal governments. It is the largest urban road project currently underway in Australia and comprises a series of interconnected motorways and road upgrades, enhancing and extending the existing urban motorway network. Over the 20year period from 2011 to 2031, Sydney's population will grow by 1.6 million people. Over half of this increase will be in western Sydney. As Sydney's population grows, so too will the demand for travel on the road network. Sydney's roads directly support around 75 per cent of the 17.6 million trips made every weekday. Given this, the number of car trips is expected to increase substantially, even in the context of significant concurrent public transport investment being undertaken by the NSW Government. Throughout this period there will be significant growth in both employment and the workforce across the Sydney Metropolitan area. However, while population and jobs will grow strongly in the western parts of Sydney, overall jobs will remain skewed towards the east. The WestConnex scheme will provide over 30 kilometres of motorway linking Sydney's west and south- west with Sydney Airport and the Port Botany precinct. 'A Plan for Growing Sydney\" (NSW Government, 2014) identifies WestConnex as essential to support major planning renewal and growth areas, including precincts in the Parramatta Road corridor which links the Central Business District (CBD) to the geographical centre of the Sydney Metropolitan area to the west of the CBD. With more than two-thirds of WestConnex being built in underground tunnels, the project will ease congestion on surface roads and improve productivity and efficiencies for all road users, including buses, freight and light commercial vehicles. In summary WestConnex will: . Support Sydney's longterm economic growth through improved motorway access and connections, linking Sydney's. international gateways, western Sydney and places of business across the city. . Relieve road congestion and improve the speed, reliability and safety of travel in the M4 and M5 corridors, including parallel arterial roads. . Cater for the diverse travel demand along these corridors that are best met by road infrastructure. 0 Create opportunities for urban renewal, improved liveability, and public and active transport improvements along and around Parramatta Road. 0 Enhance the productivity of commercial and freight generating land uses strategically located near transport infrastructure. . Optimise user-pays contributions to support funding in a way that is affordable and equitable. A scheme of the scale and complexity of WestConnex has many aspects that will be of interest to those involved in the delivery of major infrastructure projects involving underground construction. However, given the point at which the scheme is placed at the time of writing this paper is two of the four major tunnelling projects in construction, the third in the tender phase and the forth due to go to market shortly, this paper will focus on the planning approval and procurement (including finance) issues which have been addressed in reaching the current status of the scheme. In addition, the paper will also provide a brief insight into some technical matters that have also influenced the manner in which the tunnels will be delivered and briefly describe the long term operational philosophy which has, understandably, also impacted on the design of the scheme. Details of the construction challenges, which a scheme of this scale will inevitably present, will no doubt be the subject of later technical papers. 2. STAGING WestConnex will be delivered through a series of projects divided into three discrete stages. Their geographical extent is illustrated in Figure '1 below and the details of the respective projects involved is described in Table 1. As will be noted from Table 1, four ofthe projects contain major tunnelling works, namely M4 East (Stage 18), New M5 (Stage 2), M4-M5 Link Mainline (Stage 3A) and the Rozelle Interchange (Stage SB). Table '1 also provides details regarding the approximate capital cost and dates for the commencement and completion of construction for each project. 3. PLANNING APPROVAL In the past, the normal sequence for obtaining planning approval for such major infrastructure projects in NSW has involved the development of a relatively detailed concept design by the Government client which is then subjected to an environmental impact review process, often in parallel with a tendering process to secure a suitable Design and Construction (D&C) contractor. However, should the design submitted by the successful tenderer differ significantly from the concept design it may be necessary for the environmental impact process to be revisited before planning approval conditions can be finalised. This can lead to significant delay in commencing construction of the project and does have the disadvantage of presenting and explaining a different outcome to the community following the initial exhaustive impact assessments process. For Stages '18 and 2 of WestConnex an alternative procedure was adopted in which the detailed environmental impact process is only commenced once the tender selection process has been concluded and the adopted design is known. This avoids the potential need to revisit the impact assessment process and enables the detailed involvement ofthe selected D&C contractor in the impact assessment process. This does, however, mean that there is a greater delay between the award of the D&C contract and the commencement of construction, assuming that the selected design is granted planning approval. However, this time can be used to advance the detailed design of the solution such that construction can potentially commence immediately following receipt of the planning approval. This approach was seen as being better suited to the 'fast track' approach required to ensure the early commencement of these projects. By contrast, for Stage 3, the more traditional sequence has been adopted largely because there is more time available to undertake the necessary environmental assessment given that construction will not commence until mid to late 2018. 4. PROCUREMENT APPROACH Previous major road tunnelling projects in Australia have generally been procured using a Public Private Partnership (PPP) model in which the private sector takes on the risk on traffic numbers i.e. patronage once the road is open to traffic. There have been several examples over the last ten years were the initial traffic flows have been less than, and sometimes substantially less than, the numbers forecast at the time tenders were submitted. This has sometimes resulted in the original concessionaires going into receivership and the asset being sold to a second party at a heavily discounted price. Consequently, whist there is generally a strong market appetite for investments in such major infrastructure projects this is not generally on the basis that the private sector assumes the patronage risk. This led the NSW Government to consider alternative procurement models that might still capture the significant advantages of the PPP approach but address the patronage risk issue in ways more acceptable to the investment market. WestConnex is financed using \"limited-recourse project financing' and a 'sale of business' model. The key elements of this include: o A State entity holding equity in the special purpose vehicles created to deliver the project . The State acting as a 'contract aggregator' and taking the lead role on structuring and procurement . Limited-recourse private sector debt finance against future toll revenue to fund a significant portion of construction costs . Retaining flexibility for the State to progressively selldown equity in the project at appropriate points in time to optimise value. To implement the limited recourse project finance, a 'fixed price and time' design and construction approach is being used for procurement. To facilitate this: . Sydney Motorway Corporation Pty Limited, has been established to deliver WestConnex and the NSW Treasurer, the Minister for WestConnex and the Minister for Finance are the shareholders on behalf of the State . Separate project entities are being established for the delivery of each stage of WestConnex. These are wholly-owned subsidiaries of Sydney Motorway Corporation. These entities are responsible for: - Holding the long-term toll concession for their respective stage . Entering into requisite contract packages to deliver the functional components ofthe project . Raising private sector limited-recourse debt to supplement equity investment to fund construction. These entities do not represent the State and are expressly not guaranteed by the State. Any debt raised will be self-supporting and without recourse to the State, that is, there is no Government guarantee. This structure supports future sell-down to the private sector. It was originally envisaged that the three stages of WestConnex would be delivered sequentially with Stages 2 and 3 being, at least partially, financed by the sale of Stage 1 and 2 respectively once they had opened to traffic and having demonstrated that the anticipated traffic flows and consequently, toll revenues matched the original business case projections. However, largely as a result of the Federal Government making funding available earlier, Stage 2 has been procured essentially in parallel with Stage 18 thus bringing forward the delivery programme for the whole scheme N M4 East 4.5 km' | Opening 2019 Link to proposed Western Herbon Turnel" Iron Cove Link and Rozelle Interchange M4 Widening Opening 2023 7.5 kin! | Opening 2017 M4-M5 Link Main tunnel Opening 2023 King Georges Road Interchange Upgrade Opanad 2014 Now M5 Sydney Gateway"* II km" | Opening 2020 Opening 2021 Link to proposed F6 Extention" Figure 1 - Schematic layout of the WestConnex Scheme5. TECHNICAL MATTERS 5.1. Performance based specification To maximise industry innovation, procurement of each stage is based on an 'output specification approach\" which describes the performance requirements whilst seeking to avoid the highly prescriptive approach that is often adopted of major infrastructure works. Whilst a conceptual design is provided to the tenderers, a detailed design is not dictated. Instead, tenderers compete on final design solution, allowing optimisation of tunnel route, depth, intersection design, construction approach and property impacts. 5.2. Tunnel cross sections The extensive traffic modelling undertaken to date has indicated that the anticipated flows will vary substantially along the route resulting in the required mainline tunnel cross section varying from two traffic lanes to four traffic lanes in each direction. However, following past experience in which two lane tunnels have been congested earlier than anticipated, a policy decision has been made to ensure that the minimum cross section adopted is capable of supporting three lanes in the future, if necessary. Consequently, in the sections of tunnel in which lower traffic numbers are projected, a 10.5m width between barriers is provided which is initially configured as 2 x 3.5m traffic lanes and shoulders of 2.5m and 1.0m. This can later be reconfigured for three traffic lanes. Tunnels with three lanes have 3 x 3.5m traffic lanes and two shoulders of 1.0m (total 12.5m). ln sections where four traffic lanes are required to accommodate the ultimate traffic demand a width between barriers of 15.0m is provided. This is initially configured as 3 x 3.5m lanes with shoulders of 1.0 and 3.5m but can later adapted to 4 x 3.25m lanes with two shoulders of 1.0m. All the tunnels in the WestConnex scheme have a minimum vertical clearance of 5.3m. This has been selected following several over height vehicle incidents in the existing motorway tunnels where the minimum vertical clearance is 4.6m. 5.3. Geology The ground conditions encountered in WestConnex tunnelling activities are predominantly Hawkesbury sandstone which is overlain in some locations by Ashfield Shale. A narrow band of fine-grained quartzone sandstone material (Mittagong Formation) commonly exists between the Hawkesbury Sandstone and the Ashfield shale. The Ashfield Shale and Mittagong formations are often extensively weathered and the Hawkesbury Sandstone can also be heavily weathered near the surface. Hawkesbury Sandstone can be blocky with abundant cross bedding and has a high quartz content and, consequently, is very abrasive. It is, however, considered to be a good material in which to construct relatively wide spans tunnels and caverns of up to 30m in width are proposed in various locations on the WestConnex scheme. 5.4. Tunnelling equipment To date, all the major road tunnels in Sydney have been constructed using roadheaders rather than TBM's, although they have been used extensively for rail projects. There are several reasons for this, including: o The tunnels cross sections are often frequently variable cross section requiring significant either 'over excavation\" of a circular profile or advance construction of cavern sections. . The local geology being predominantly Hawkesbury sandstone is particularly well suited to the use of roadheader machines as it requires minimal primary support prior to excavation advancing. . None of the road tunnels constructed to date in Sydney are undrained. . Very short overall tunnelling programs can be achieved by employing multiple machines at number of headings. For example, the Stage 18 and 2 Contracts currently in progress are each employing approximately 18 roadheaders respectively (total 36) to achieve the earliest possible completion dates. 6. OPERATIONAL PHILOSOPHY As outlined earlier, the WestConnex scheme is being delivered in a staged manner, albeit that Stages 1 and 2 are being undertaken practically concurrently. It should be noted, however, from Figure 1 that Stages 1 and 2 are physically remote from each other and the scheme is only continuous when Stage 3A is constructed. Given that Stages 1 and 2 were to be delivered under separate D&C contracts, initially with a sequential rather than parallel sequence, the decision was made at an early date to operate these stages separately and consequently, separate Motorway Control Centres (MCC) are provided for each stage. These centres provide the normal 24/7 control room facilities with total operational control including full CCTV coverage. At least initially, maintenance activities for the respective stages will also be provided from these control centres. Given the geographic separation of these stages, when they open to traffic in 2019 and 2020, respectively, they will be operated effectively on a stand-alone basis. However, once Stage 3A opens by 2023, the three stages will be physically linked and from a driver perspective they will be perceived as one continuous motorway tunnel. Consequently, even though the stages could be owned by different concessionaires at the time, any commercial arrangements need to be subservient to the need to ensure that there is a totally seamless operation ofthe tunnels to ensure that the driver experience is optimised and a safe operating environment is provided. Considerable thought and planning was dedicated to this matter by the Sydney Motorway Corporation in developing an approach which would ensure that, particularly in an emergency situation, there would be only one operator controlling all the tunnel stages in the overall scheme. This \"one captain' approach was not initially seen as the optimum commercial approach, where the respective concessions may have taken the view that their business interests are best ensured if they retained full control of their asset. However, it is now widely recognised that the interests of all parties are best served by the efficient and coordinated management of the whole scheme both in normal and emergency operational scenarios. As a result of this philosophical approach the operational sequence adopted is as follows: . Stage 1 constructs an independent MCC which controls operations and maintenance from mid 2019. 0 Stage 2 constructs an independent MCC which controls operations and maintenance from 2020. However, this facility is designed so that it can be expanded to provide operational control for all three stages when Stage 3A opens by 2023. . Thereafter the Stage 1 MCC will act as a disaster recovery centre for the whole scheme in the event that the combined operations centre is not operational for whatever reason. 7. CONCLUSION The WestConnex scheme represents a quantum step upgrade to the Sydney Urban Motorway system. It has been a decade since the last significant upgrade to the system with the consequence that congestion has increased significantly on the network. The anticipated growth in traffic over the next twenty years demands that such significant response is now implemented. The procurement model adopted for WestConnex is highly innovative and seeks to address the problems that have arisen in recent years in the delivery of such major urban tunnelling projects through the PPP procurement approach. Finally, the operational philosophy developed for WestConnex recognises the importance of ensuring that a series of continuous motorway tunnels are managed in such way that the road user is presented with an integrated driving experience and is provided with a safe and efficient environment. 8. ACKNOWLEDGEMENTS The author gratefully acknowledges the consent of Sydney Motorway Corporation Pty Ltd to the submission of this paper to the Australasian Tunnelling Conference 2017. 9. REFERENCES 1. AECOM. 2016. M4-M5 Link, Concept Design Report. 2. NSW Government. 2014. A Plan for Growing Sydney. 3 . NSW Government. 2015. WestConnex Updated Business Case. 4. NSW Government. 2015. M4 East, Submissions Report. 5. NSW Government. 2016. New M5, Submissions and Preferred Infrastructure Report. . MacDonald C.C., Planning, design and construction of the WestConnex underground motorway project , Sydney, Australia, World Tunnelling Congress, Bergen, Norway, 2017 7. Roads and Maritime Services, 2015. WestConnex New M5, Environmental Impact Statement