The Combined Services
Route (CSR) project is for the proposed new city rail services from Glenfield to
Leppington in NSW (GLRL project). The project involves the design of about 10km
of rail track including earthwork, buildings, stations, roads, bridges and all
the relevant power and signal services. GHD received the previously designed
rail and surface tin, and was then involved in modelling the cables consisting
of high-voltage cable, signal, and communication conduits running along and
across the rail corridor.
The various cables were modelled as conduits arranged in
combined configurations running inside the different sizes of trenches. There
were several hundred pits of various sizes for cable pulling and changes in
directions. There were trenches that went across and under the railway (called
ULX) and also cables above the ground placed inside galvanised service troughs
The CSR designed very often
clashed with the drainage, sewerage and other objects. The earthwork, drainage
and sewerage network were designed by different consultants.
As a result, the CSR route changed in location and height
to accommodate various design and economic requirement, almost on a daily basis.
Similarly, the pits, GST and ULX moved very often. There are hundreds of Apply
Many functions that generate trenches and conduits along the 10km alignment with
chainage generally corresponding to the pit locations. Any changes in length of
the CSR and pit location require the chainage value in the MTF to be updated.
Manually updating chainage in the MTF is very time consuming. A self-updating
chainage MTF is required.
The configurations of the conduits are changed frequently,
hence the templates need to be updated quickly. Manually updating the link in
the template is time consuming and error prone. Tabulation of the template in
Excel is required for other non 12d users for reference.
The pit quantity and locations are also changed
frequently. The pits need to be shown in 3D for visualisation. Due to frequent
changes in the design tin, a drape process had to be applied to the 3D pits.
In the visualisation process, the “string drive” video ran
the entire length of 10km while still be able to provide a clear visual of the
underground conduits, hundreds of 3D pits and its relationship with the other
objects and the finished surfaces.
Both the conduits and
trenches were modelled with templates running along the superalignment with
Apply Many functions. There are two very long super-alignments (the Up and Down
Main) with more than 10km and several shorter ones. The configuration of
conduits and trench sizes are grouped by types in alphabetical order.
The conduit super strings generated (which represent the
HV, Sig and Com) are mapped to their respective diameter and colour with a map
file. Pits are drawn in another package as single vertice blocks with individual
embedded names. They are draped on the finished design surface but need to be
output as 3D pits.
The outputs from 12d are the long sections, cross
sections, pit schedules and visualisation.
Chains provided automation that sped up work and minimised
error. Using the latest 12d modifier and computators, the chainages in the MTF
were automatically updated with the change in the main alignment. Using
computators, hundreds of marker point strings (in numerical order) were created
to compute the intersections of the CSR alignment and the pit locations (the
point where the type of template will change). In a chain, the resolve commands
updated their locations automatically. The templates were inserted via the MTF
modifiers (fixed insert: start of other strings) that start from one marker
string and run to the end of the next marker string. When the MTF functions were
rerun in a chain, the conduits and trenches were updated automatically without
manually updating the chainages.
The new conduit configurations were drawn in CAD.
Initially the link of the templates was drawn as polylines in CAD by the
drafting team. A simple list command extracted the info and pasted it into
UltraEdit. The XY coordinates were then pasted into Excel spreadsheets that also
generated the text version of the 12d templates. The templates in text format
(in the form of ‘.tpl’ files) were imported into 12d. Most of the generation of
templates, MTF and chains was done using UltraEdit and its scripts.
Pits are imported as vertices and draped onto designed
surfaces. Each type of pit carries its respective symbol. DWT files were created
with the corresponding 3D blocks. Hence the exports from 12d were 3D pits with
updated levels (Z-values). Later the 3D pits were re-imported (with Explode
selected) into 12d Model as 3D objects for visualisations For visualisation, the
using of mesh instead of texture tin enabled the underground pits and conduits
to be clearly seen, while providing a feel of the design surfaces.
Some structures were rendered as faces to show the solid
objects. Billboards with text of the chainage (in kilometres) were placed along
the master rail corridor to mark the locations.
The use of 12d Model on this
project has enabled on-time completion and satisfied client requirements.
Although no complicated macros were used, the application was innovative,
particularly in draping 3D pits, auto updates of chainages and creating
templates using Excel/UltraEdit.
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