The construction of a 4.7km gravity trunk sewer main
consisting of trenching and micro-tunnelling methods.
The WGTSM project is the construction of a 4.7km gravity trunk sewer main
consisting of trenching and micro-tunnelling methods. The project location is
Brookwater to Goodna, approximately 25km Southwest of Brisbane CBD. Half the
project zone is in a residential setting and half green-field. Thiess was
engaged as project surveyors from the early stages of design, right through
In the early design
phase, site engineers and project managers were finding it hard to relate the
new design changes to real world locations. Because many of the new manhole
positions involved green-field locations, it was hard to relate this to the
ground. Often they would require survey to travel to site and set out the new
design locations even though they did not require survey accuracy for the
purpose of walk through assessments. This was not cost effective, so a solution
It is said the best ideas
are often the simplest. As intermediate users of 12d Model, Thiess didn’t want
to ‘reinvent the wheel’, so they combined existing options. While not needing
complex 12d functionality, they were still able to use 12d in an innovative way
to solve the problem.
They simply output their 12d design data to a .kml
format so the data can be viewed within Google Earth on smart phones on site
using the phones’ location capabilities. This allows engineers and designers to
view design options on the ground without the need for survey to pinpoint
locations for them.
To streamline the process, they made a toolbar that
runs a .slf of a Helmert 2d Transformation that moves the data from the site
coordinate system to MGA94 and then another .slf that outputs to kml. Hence,
with 2 clicks they have a file ready to be viewed in Google Earth which can then
be email off to selected recipients. This can be achieved form their survey
office without the need for any field visits.
Some benefits over
conventional handheld GPS include:
• Handheld GPS units do not allow this
instantaneous upload of design and design changes from 12d Model
GPS units have sky-view limitations where modern smartphones can augment the
positioning with network solutions allowing use in areas of dense vegetation and
difficult topography beyond the reach of GPS
• Most engineers and
construction managers have a smart phone
When a design change occurs,
they can have the new design in the site personnel’s pockets within minutes and
opened in Google Earth. The use of a 12d screen layout file makes this a much
faster process with and also eliminates the chance of gross errors or typos.
By using the location features on their phones (GPS and phone network
location), they can ‘walk’ through the site and see the new design planning and
moving on their screen.
The only limitations here are the accuracies of
each phone’s location capabilities, but checks have found they were usually
within 2.0m. This is more than enough to allow the site personnel to see if the
design is viable and will ‘work’ in the field.
There are mobile .dwg
viewers on the market, but these don’t allow the user to relate it to the
ground, so that is why this 12d to .kml option is vastly superior.
phones (or even Android/Apple tablets) are becoming common as an everyday
business tool. They will be implementing this 12d to kml viewing on all our
construction sites in the future.
This process has only been used to date
on Android system smart phones running the Google Earth application and an
additional app called KMLZ to Earth which allows KML files to be viewed in
mobile Google Earth. The iPhone is fully compatible but has not been used by
Thiess. Both apps are available free from the Marketplace.
A Senior Engineer from the project stated,
“The ability to not only view the design data but view it in real world is
incredibly beneficial. This really needs to be experienced to fully grasp how
useful this concept is and realise its full potential.”
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