The design and construction of major transportation systems, such as, airports, ports and metro rail requires meticulous planning and execution to deliver ‘fit for purpose’ transport infrastructure that delivers lasting benefits. Transport hubs seek to connect large volumes of passengers and freight with seamless connections to forward services. A key success of these hubs is the efficient movement of people and goods through the entire transport system.
“Construction phase transport planning is critical to ensure successful delivery of major infrastructure projects,” says David Ness, Service Group Leader, Transport at Aurecon. “This is even more important as we seek to retrofit and upgrade our cities and existing infrastructure.”
Construction in urban brownfield sites, such as existing airports or core business areas for urban rail, can pose a significant challenge to maintain access and transport services for existing users while accommodating construction traffic. This issue can be compounded by the need to close vital transport links, such as roads, for construction resulting in diminished network capacity at a time of peak demand.
Metro rail is a prime example of complex brownfield development, often requiring the closure of core CBD streets to construct stations and adjoining commercial zones. This can lead to impacts on existing users (access to buildings and services) and surface level transport provision (public transport, general traffic, pedestrian and cyclists). In addition, the ability to service the construction site with labour, materials and supplies requires construction traffic to navigate congested urban streets.
These projects need to strike a balance between a solution that provides sufficient access for the construction team while maintaining a suitable provision for community that is both socially and politically acceptable. The consideration and development of a construction phase transport plan is key to the success of these projects. The development of the plan is also an essential measure to identify and mitigate project risks and provide confidence to the project team of successful completion of the project.
“The primary goal of construction transport planning in a brownfield setting is to minimise the impact of construction on existing transport users and maintain safe access and mobility for community,” says David Radcliffe, Industry Director, Transport.
“Undertaking construction in a confined environment, such as a city centre, it is imperative to ensure reliability in the supply of materials to site and minimise the dwell time of materials at the site. That is, in an ideal world materials would be delivered to site when they are needed thus reducing the need to stockpile or store products on-site.”
In a congested urban environment, this can pose an issue as delay associated with congestion can create variability in travel time to site. Delayed receipt of inputs can impact on overall construction efficiency.
To mitigate against such events it is commonplace to secure a staging area in proximity to the construction site. This is an area where materials can be received and stored in preparation for a short trip to site when required. This approach has many advantages. Firstly, the receipt of materials in advance gives certainty to the construction team ahead of installation.
Conversely any delays in receipt can be communicated to the construction team to plan and adjust activities accordingly. Secondly, locating the staging area in proximity to the construction site ensures consistent travel times of the materials to the construction zone maintaining the overall efficiency of the construction site. Similarly minimising delay for existing transport users is of an equal importance.
This can provide useful feedback such as optimal route selection to avoid congestion and identify non-peak time period which facilitate reduced travel times. Also, existing transport operations near the site can be monitored to ensure the works do not impact on the wider transport network.
Successful planning requires a customer centric focus, which minimises the impact of works and delays on existing users while facilitating efficient construction. This needs to be fully understood and embedded into the framework of the construction phase transport plan.
For example, it may be a requirement to maintain a public transport route or Disability Discrimination Act compliant access path around a site, which means it may be an objective to minimise delay for these users. Identifying these requirements and objectives provides the project team with a clear framework to consider solutions.
“A reduction in road network capacity may require the provision of additional capacity elsewhere in the network. For a recent city centre water-main renewal project in Melbourne, Australia, that required extensive road closures, Aurecon worked proactively with relevant responsible authorities to identify and provide capacity elsewhere in the road network,” says David Ness.
This was accomplished through remodelling traffic signal sites and optimising feeder routes. These solutions were tested and refined using a city wide microsimulation traffic model. This provided confidence to stakeholders that key streets could be closed without adversely impacting on the wider transport network.
Our integrated approach to metro design allows us to work seamlessly with range of technical professionals such as construction experts and station designers to identify optimal staging arrangements for stations.
The focus of this task is to minimise the number of construction stages or changes to surface level transport in while providing sufficient space and access for station construction. Multiple stages result in delay and inefficiency of construction as time and effort is lost to adjust the site boundary and set up traffic management. From a user perspective, multiple stages can lead to frustration due to the additional time impact to construction and the difficulty in wayfinding around a constantly changing site. The benefits of this integrated approach are the ability to maintain existing surface transport while improving the overall efficiency of construction, producing a win for all stakeholders.
“To improve project performance, Aurecon has recently partnered with an asset owner to develop a planning tool which forecasts future traffic movements to assist in proactively managing traffic during construction,” says David Radcliffe.
“This tool has the ability to consider existing transport movements, future construction movements, future operations post-construction and adjustments in the transport network to reflect construction and the commissioning of new transport links.”
The strength of this tool is the ability to identify the peak period of activity on-site and assess whether sufficient network capacity exists. If not, the user can determine whether to develop additional infrastructure or alternatively alter the construction program or hours of operation to reduce activity on-site.
The solutions above are just some of a suite of measures which can be applied to ensure effective construction phase transport management. As our cities grow and evolve the upgrade of existing and provision of new infrastructure requires construction in complex urban environments. Construction phase transport plans consider the potential transport impacts of construction and identify solutions to guarantee successful project delivery.