CLEM7 and Legacy Way - Volumetric Land Resumption
Project Summary
This 12d Model component here outlined was used across three major tunnelling
projects - CLEM7, Legacy Way, and (to a lesser extent) the early stages of the
Airport Link. The requirement was to produce information suitable for the land
resumption process, which required plans for the Notices of Intention to Resume
as well as final survey plans for registration and title transfer.
The Challenge
Problems faced included the calculation of hundreds of volumetric resumption
lots for major road tunnels. CLEM7 had approximately 330 volumetric resumptions,
and Legacy Way had approximately 420 volumetric resumptions.
The acquisition of the volumetric parcels
had to be achieved so that the tunnel constructors had access to construct the
tunnel, and the tunnel operators could be granted title to the tunnel to satisfy
their bankers and be able to charge a toll. There was considerable risk to the
Brisbane City Council if access to the land was not available for the
constructors, and/or if the operators could not be given a lease at the
completion of construction.
The information
required included the xyz locations, bearings and distances; volumes, areas,
surface levels; and average depths of the volumetric parcels.
There was a risk that for various reasons the calculations may have to be
repeated and plans redrawn.
The team needed
a consistent process that was applied to all land parcels, and was repeatable.
At the very least, they needed results that would be defensible and
reproducible.
Several survey suppliers were
engaged to draft the plans, so it was necessary to be able to manage the files
so they could be processed collectively and separated so the relevant
information could be distributed to the relevant supplier.
The Solution
The problem was solved by the writing a macro (approximately 2500–3000 lines of
code) to calculate the intersections of the tunnel resumption envelope with the
surface cadastral lots. The surface cadastre was surveyed, reinstated and
connected to the coordinate system that was used for the tunnel construction.
This macro could calculate all the information necessary to produce survey plans
of each lot along the entire length of a tunnel in minutes. The macro calculates
the information for an individual volumetric resumption as a 12d model and
produces a summary report of all the parcels calculated and an individual report
for each parcel.
It was necessary to relate
the volumetric resumption lots to the surface terrain to calculate depths to the
volumetric lot. This was achieved by using a surface TIN created from LiDAR
data.
The resumption calculation macro was
supported by other macros to load the surveyed cadastral parcels, check the
parcels for overlap or gaps and to load and check attribute information. Output
of .12da files and 3D .dwg files was done using a ‘bulk’ writer macro to manage
the writing of the data to sub folders for each survey plan supplier.
The macro proved its worth when the volumetric land requirements were delivered
well before the due dates. The flexibility provided by the macro was
demonstrated when one of the projects changed the resumption requirements after
one set of calculations had been completed, and the process had to be redone and
the information issued a second time. The recalculation caused minimum delay to
the project.
A by-product of the process
was the ability to graphically track the progress of the supply of plans.
Using the attributes it was quite easy to colour code plans by their status,
e.g. ‘no plan’, ‘proposal plan commissioned’, ‘proposal plan delivered’, ‘survey
plan commissioned’, ‘survey plan delivered’.
The Result
The innovation demonstrated in these projects allowed the team to combine the
functionality of 12d Model (such as TIN manipulation, string manipulation,
volume calculation, database manipulation, macro coding etc.), to produce a
result that does not fit into the standard range of 12d outputs and make their
work on these projects much easier.
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