Completing a missing link between Sydney and Bomaderry

Expertise

Completing

a

missing

link

between

Sydney

and

Bomaderry

Delivered six-months ahead of schedule, the Albion Park Rail Bypass will significantly reduce congestion and improve travel times on the M1 Princes Motorway.

Over the past decade the greater-Sydney region has experienced unprecedented growth, a trend which is only expected to gain momentum. To support economic sustainability and transport connectivity as the population increases, significant investment has been made in the construction of new motorway infrastructure, including the Albion Park Rail Bypass (APRB), which welcomed its first motorists in mid-2021.

The APRB completes the missing link between Sydney and Bomaderry, bypassing the community of Albion Park Rail which is located approximately 100-kilometres south of Sydney. It is a motorway-standard highway with four grade separated interchanges, 13 bridges, a shared user path and local road connections to improve community connectivity.

Our role

We were engaged by Fulton Hogan to provide detailed design services including alignment, drainage, flooding, geotechnical, structural and pavement design. Over the two years of construction we formed a strong partnership with Fulton Hogan and delivered exceptional project outcomes.

Year

2019-2021

Location

Australia

Client

Fulton Hogan

reduction in bridge length from the Reference Design

2020 Winner Australian Engineering Excellence Award

bridges

over 9.8km

30-50% reduction in design turn-around times

The Albion Park Rail Bypass is an example of design innovation which solves the significant engineering challenges in delivering a motorway-standard highway along a route with alignment complexities and difficult geotechnical and hydraulic conditions. Our teams work hard to deliver industry-best projects, through a combination of teamwork, innovation, and technical excellence. We’re fortunate to have the opportunity to support our clients on exceptional infrastructure projects like APRB.”

— Andy Baxter, Team Leader Roads and Highways Design, SMEC

Overcoming challenging conditions to deliver engineering innovations

In partnership with Fulton Hogan, we implemented a detailed design that addressed the site’s complexities through innovation and value engineering.

In designing five bridges, three key engineering innovations reduced the total bridge length (across the project) by more than 150 m, representing a 30 per cent reduction in bridge length from the Reference Design and providing a few million in construction savings to the project.

In making design improvements, our specialist teams made best use of the available land that had several challenging elements. The APRB is adjacent to a nearby airport, and is located on a flood plain, which features soft, compressible soil. It is also close to the nearby railway line and existing highway.

Innovation One: Utilising pergola-type deck design

The first innovative solution our design team introduced related to the complexity of the structure. The main alignment for APRB crosses over the existing South Coast Railway Line corridor (Bridge 04), the existing Princes Highway northbound carriageway (Bridge 03) and the new Oaks Flats Interchange northbound entry ramp (Bridge 13). At these sections, the bridge structure skews were significant and ground conditions differed greatly, adding to the complexity of the structure. Therefore, the revised designs had to provide a simple solution that was more practical and cost effective to construct, with reduced span lengths and limited temporary works (especially for Bridge 04 crossing the rail corridor). As the structures traversed busy or difficult-to-access corridors, maintenance requirements needed to be reduced wherever possible. We considered designs of traditional structures; however these designs were discounted due to complex temporary works requirements.

We overcame this challenge through an innovative pergola-type deck design for the three structures. Bespoke planks were used for structures which reduced structural depth, reduced the number of piers in the flood plain by increasing span lengths. This also achieved significant design and construction cost savings and reduced construction time on site.

Innovation two: Stretching the standard spacing of precast elements

The second innovation aimed to optimise the efficiency of the bridge from a flooding perspective. Twin bridges over the Macquarie Rivulet (Bridge 06) and twin bridges over Frazers Creek (Bridge 07) cross a floodplain and were constrained by the local airport Obstacle Limitation Surface (OLS), which meant there was limited structure depth available for the structure. Our structures team were tasked with reducing the length of the bridges where possible, working with the flooding team to provide a coordinate design solution.

Our design stretched the standard spacing of precast elements, to reduce the number of planks required in each span. This solution, maximising span lengths to reduce the number of piers in the floodplain, will optimise the efficiency of the bridge from a flooding perspective, which will allow the reduction of five other bridges within the floodplain.

Innovation three: The unconventional use of lightweight fill

To address issues relating to the building of a large embankment over problematic ground conditions, we worked with Fulton Hogan to optimise the soft soil design. Together, they identified an innovative, unconventional approach using lightweight fill solution instead of adopting convention earthworks.

This geotechnical solution optimised the construction program, allowing bridge construction to commence earlier with less impact to residents and road users, while reducing the diameter of the piles and improving safety.

Importantly, these innovations provide the opportunity to cater for similar innovative structures and methodologies in the future, compounding future clients’ cost, program and safety improvements.

Innovative use of technology to improve workflow efficiency

Historically, industry-standard design processes are labour-intensive, relying on 2D drafting, string-based modelling and constant static updates from the road designers to the structures team. This is not only time consuming but also increases the possibility of human error and a communication disconnect. Traditional Autodesk® Revit workflows did not allow for automation improvements.

Through careful collaboration and a strategic partnership with Autodesk®’s development team, we rapidly developed and deployed a method for using Autodesk® Dynamo as a conduit between Autodesk® Civil 3D and Autodesk® Revit, to easily combine road and bridge design modelling, reducing design turnaround time by 30 to 50 per cent.

By introducing high levels of automation, we were able to deliver a compliant bridge design with reduced design risk and increased agility in reacting to design changes for the project.

Autodesk® has now packaged this innovation as a discrete software offering, available as the Autodesk® Model Authoring Foundation. This represents a significant step forward for the industry for future projects of a similar scale. We have also standardised these innovative technologies and workflows across our business, enhancing our ways of working and gaining efficiencies for projects in the future.

Award-winning solutions

Across the project, our innovation and engineering excellence has saved hundreds of hours in design, with significant construction cost saving and completion ahead of schedule. Our specialist teams used technical innovation to set new benchmarks and maintain high standards for Australian engineering. In recognition of the excellence achieved on this project, our Detailed Design was recognised as the 2020 winner of the Australian Engineering Excellence Award in Sydney.

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