A motorway upgrade project in Australia employs a range of software platforms to improve road infrastructure and attract the best specialists available.
Already one of Brisbane’s busiest road networks, the Centenary Highway Interchange was expected to get considerably busier according to demographic projections.
As the two main arterial roads for commuters from Brisbane’s outlying south western suburbs, the capacity of the Ipswich Highway, which goes underneath the equally busy Centenary Highway from Springfield had to be increased. The government’s plan was to provide a free-flowing interchange, improve the existing road geometry/pavements to alleviate long commute times, and increase road safety.
In addition, some portions of the roadway were at relatively low elevations within expected flood levels and the original interchange divided the surrounding community with unattractive landscaping.
The Department of Transport and Mainroads Queensland awarded the contract to the SAFElink Alliance, a consortium of four partners that included Arup, a global firm of consulting engineers and designers. The project is currently under construction and due for completion in 2010.
Linked in project design
The SAFElink Alliance needed to keep traffic flowing throughout the upgrade as well as meet high sustainability standards. Environmental and community impacts during construction had to be kept to a minimum, with local sports grounds and facilities needing relocation. At the request of contracting agencies, compulsory land acquisitions had to be kept to a minimum while providing for future expansion.
SAFElink Alliance divided the project into three phases. In phase one, target cost estimates were set and benchmarks were established to guide design and construction. Phase two was devoted to design and optioneering, in which the team evaluated and costed many options, trying to capture as much innovation as possible. In phase three, solutions were selected and conventional design and construction began. “These steps created significant pressure for the design team. Innovative design, process, and procedures were required to successfully achieve all program milestones,” said Andrew Lewis, an associate at Arup.
One challenge that the SAFElink Alliance struggled with was a shortage of skilled design talent. This was overcome with two strategies. First, a decision was made to use MicroStation PowerDraft and Bentley MX as main interchange design tools. Team managers felt that MX, in particular, was relatively intuitive and could be taught quickly to new employees. Also, because these tools are fully interoperable with other design platforms, the SAFElink Alliance was able to make full use of designers who were conversant with AutoCAD.
Similarly, when doing specialised work like 3D lighting modelling or landscape design, the SAFElink Alliance team could employ the best specialists or consultants available, regardless of what software tools they preferred. The second strategy grew out of the first — because interoperability was not an issue, the SAFElink Alliance could use Bentley ProjectWise collaboration software to co-ordinate the work of teams around the globe.
By accessing skilled engineers wherever and whenever they were available and letting them work with their preferred tools, the SAFElink Alliance successfully overcame talent shortages.
Virtual and physical models
Models were used during the optioneering phase to visualise and evaluate features. Ultimately a parametric model built primarily with MicroStation PowerDraft and MX was completed, and the SAFElink Alliance was able to use this to refine materials lists and cost estimates. The MX model could also be used alongside structural modelling tools like TriForma and with non-Bentley tools used for traffic modelling, 3D lighting design, and urban landscape design. The design team used MicroStation PowerDraft visualisation tools to communicate design decisions to all stakeholders.
As segments neared final design, the electronic model could also be transferred to construction and survey teams, reducing the number of construction documents that needed to be produced. The use of videos for sight line checks, cross section reviews, and aqua planning analysis also reduced document quantity.
To convey the design to the client, stakeholders, and local community, visualisation videos and animations were produced from the design models. These were also used by television networks to announce the project in the media. A subconsultant, Urban Circus, was employed to further develop the model creating a real-time model for use during the public consultation phase, which allowed virtual walk-throughs of the project as it neared completion.
To meet stringent sustainability requirements, designers paid close attention to the amount and sources of materials used. Innovative design reduced the amount of bridges needed, thereby reducing the amount of material needed. Batching plants, precast yards, and crushers were set up on site to recycle and reuse some existing structures as fill, and other local projects were also used as material sources. This greatly reduced the amount of material hauled in and out of the construction site. The use of ProjectWise as a collaborative tool to co-ordinate the dispersed design team also cut travel, thereby further reducing the project’s carbon footprint.
Addressing all these issues with one upgrade and rehabilitation project called for innovative thinking and project management, even when working with a budget of more than AU$863 million (US$783m).
In the fast lane
The project has already significantly reduced accident rates due to improved road geometry, better signage, less distracting urban landscaping, and intelligent transport systems. Improved lighting design, facilitated by advanced 3D modelling techniques, is another contributing factor. Raised highway levels and more effective drainage have made the interchange and the surrounding neighbourhoods less subject to flooding, and by opening portions of the upgraded interchange in planned phases, commute times have dropped, even during the construction period.
By redesigning from a perspective of connectivity, the surrounding communities are no longer split in two by the interchange. The community also benefits from landscaping, which improves views and buffers motorway sounds, and from better and lighting that is more considerate of the interchange’s neighbours.
By any standard, this was a challenging project. But it was also one in which designers had the opportunity to make life better for commuters and residents. By using specialised talent and tools, that chance was realised.