An exciting construction project for Sydney CBD infrastructure - the CBD and
South East Light Rail (CSELR). The 12 kilometre alignment features 19 stops,
extending from Circular Quay to Central Station, through Surry Hills to Moore
Park then branching off to Kingsford and Randwick. The project included 10
substations, a stabling yard, and a maintenance facility.
The CSELR was designed, constructed, operated, and maintained by a private
operating company as part of a Public Private Partnership (PPP). The PPP
contract was awarded to the ALTRAC Light Rail Consortium, which included
Acciona, Alstom, Transdev, and Capella Capital.
Land Surveys was commissioned by Patriot Environmental Services. Patriot was
engaged on the project to provide the non-destructive digging services. This
system is used to safely expose the utilities in order to treat them, or
relocate them. Patriot engaged the vast skills of Land Surveys for surveying and
utility mapping to be undertaken.
Land Surveys was tasked to map all the existing utilities and associated
structures through the Surry Hills zone, which is from Central Station, through
to South Dowling Street, Surry Hills via Devonshire Street.
There were multiple challenges involved, including the rail being constrained by
its horizontal and vertical geometry, as well as being in the middle of
Australia’s largest and most densely built up city. This resulted in the need to
treat the existing utilities required to protect them from any vibration and
active loads from the rail, or completely relocate them outside the construction
The service records showed that some of the services were more than 100 years
old. Some records were incomplete, or missing, creating a significant challenge
on the project. In addition, more than 1,500 undocumented services were
identified across the alignment during the service mapping and investigation
work completed by Land Surveys with other service locating companies.
The scale of this project was exceptionally large, and as such, it took a lot of
resources and coordination. Consultation was required with each asset owner, as
well as an assortment of required permit grants, whilst maintaining utility
supplies to schools, businesses, and homes at all times in the area.
The first step was to document all the existing services. This was done via
locators to mark out the information on the ground, along with undertaking
investigative trenching. The data was then captured using 12d Field software. As
there was a vast number of services to document , the team used 12d Model map
files with 12d Field code lists to allow them to process the data as they picked
it up. This allowed them to see any errors or issues immediately. They
documented this information with the required GIS database attached to each of
the CAD elements as per the AS5488-2013 including additional attributes relevant
to the project. They used the attributes to get 12d Model to auto pipe and
culvert the services to display their extents, as some services banks were more
than 2m wide and more than 1m thick. There were pipes nearly 1,200mm in
diameter. This information was critical to understanding the space they were
working with, and to ensuring they met the separation distances required by the
safety in design specifications.
After collecting the data, it was sent to the client’s design team to design the
models. The design team was also using 12d Model to design the utility model
placements and civil design. Due to their use of 12d Model, they could provide
12da files that Land Surveys could easily drop straight into their 12d Model
project files, and overlay to their survey models. This enabled them to
instantly see the relationship between the design and the existing services, in
They then went on site and marked up those designs using 12d Field. At this
point, if any engineers, supervisors or construction crews had any queries
around measurements, or separations, the Land Surveys team was able to answer
those queries onsite. They were also able to pull sections and add data in as
needed, generate reports and distribute important information all from the
field. Any new data collected was automatically processed as described above.
Once the pickup was done, there was little to no additional processing required,
and with 4G data access, they were able to email the collected data fully
processed straight to the client and their design team, removing the time loss
of having to go back to the office. This whole process saved large amounts of
time by increasing the efficiency of the crews in the field, and allowed the
engineers to make important decisions in the field much faster and more
Designs were being developed mainly based on ‘B’ class data with accuracy up to
500mm vertically and horizontally. When the design model was issued, the
accuracy of the existing utility model was improved by being upgraded to ‘A’
class through investigation trenching, resulting in some clashes. Clashes had to
be detected as soon as possible to allow the designers to rectify significant
clashes. Using the clash detection functionality in 12d Model, the Land Surveys
team was able to identify any clashes as the existing services model improved.
The client was then notified immediately and issue alerts generated. The
designers were also notified, enabling them to adjust the design accordingly
while still under the review and endorsement process. Most, if not all, of the
issues were rectified prior to the main scope of works commencing, reducing the
chances of any delays by the work crews (and associated costs).
To ensure safety onsite, the project required an excavation permit to allow the
teams to safely excavate. This was achieved by ensuring each excavation was
marked up by the utility locating teams, and the crew’s walk-through, in regard
to the services they were working around and the restrictions that were in
place. The teams used the utility model Land Surveys had generated in 12d Model
to ensure all services were located and marked up on the ground, given they
could not rely on the DBYD as the DBYD did not include decommissioned services,
property connections, or any of the 1,500 undocumented services located. The
team was also able to use 12d Model software to extract out attributed data such
as the pipe size, the configuration, the material type, and the extent of the
banks. Land Surveys, along with the Utility Mapping teams, helped run permit
training with competency tests to ensure the crews working around the live
services could understand the marking on the ground, in accordance with AS5488,
along with the procedures and restrictions required by the asset owners for
working around live services.
By applying these processes and using the intelligent functions of 12d Model in
the field, the project was able to bring the service strike rate and near miss
incident rate involving utilities down significantly.
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