Automation of redesigning (regrading) the vertical alignment of a surface
based upon surveyed points or known differential values.
During the process of construction, it is not uncommon that a proportion of the
surface does not meet the final design (tolerances) or specified minimum layer
thicknesses. In such circumstances, it is possible that the contractor may incur
a penalty for being outside specifications, or have added costs in materials for
It was with this in mind that LendLease
(then Abigroup) first developed a spreadsheet that allowed semi automated
regrading to conform to RMS (previously RTA) specifications.
The spreadsheet worked well for providing
a solution to the regrading of a surface, but required many steps to calculate
values, as well as an innate knowledge of the regrading process to ensure errors
were not overlooked.
Another macro was developed by an external
source that was also semi automated and required many steps to provide a
As 12d Model software was already in use
by the survey department across Abigroup as a whole, it was decided that the
only way to improve and standardise the process was to provide an ‘in house’
solution that manipulated the data directly to and from 12d Model in a manner
that suited their requirements. This also meant that it could quickly be
distributed across the company with very little training due to the familiarity
of 12d Model.
12d Model software was employed as the main component of the regrade program,
with support from the Embarcadero Delphi programming language. A 12d Model macro
was written that would accept the survey data and provide conformance
information. This information, combined with the design data and user selected
criteria (e.g. ride quality and thickness), was passed to the Delphi module, and
the regrade function them took place.
Users could specify fixed locations within
the data (such as bridge abutments or existing tie-in points) and decide upon
the vertical rate of grade change allowed. The program combined the data and the
parameters and through an iterative process produces, within 12d, created new
design strings to satisfy all criteria. If satisfying all criteria was not
geometrically possible, the user was notified and could then choose to modify or
accept the input information.
It is vital to maintain traceability of
data; therefore user parameters such as lot number, user, date/time of regrade,
original z value and comments were passed from the Delphi module to 12d Model
and saved within the new design strings as attributes.
The interface of the program is very user friendly, and for an experienced
Abigroup 12d operator posed no problem with either data input or assessing the
The development of this powerful program greatly reduced the time taken to
regrade a surface. It provided Abigroup with cost and time savings, as well as
increasing the quality of the finished product for clients.
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