SURPAC
Surveying
Software
The
SURPAC ENGINEERING Module
Applications 
Horizontal Curve and Straight Alignment

Given
a set of user defined parameters for a road or railway route containing a
series of horizontal curves, this application will compute the [Y, X]
(or [E, N] ) coordinates and Chainages of positions along the centre
line of a route, or along a defined Offset Line.


The
required input parameters are :

The
[Y, X] (or [E, N] )
coordinates for the Start and
End points of the
section of the route to be computed, plus the chainage of the Start point. These Start and End
points represent the total length of the centre line, or offset
line, to be computed.


The
[Y, X] (or [E, N] ) coordinates for the Points of Intersection for all curves lying along the defined route (up to 100
curves).


The
circular Radii for all curves lying along the route.


The
lengths of all Transition curves, if any, for all the curves along the
route.


The
Chainage Interval required between Centre Line points.


Selection
of Centre line or Offset calculations.



The
route section can also be as long, or as short, as required.
It may consist of a single curve (where the start and end values may
be coincident with the BC and EC points), or a single straight. The maximum
number of points on any Centre Line file is unlimited.


Once
a route, or section of a route, has been computed, this application may be
used at a later date, for the editing of any of the curve parameters, if required.
Curves may be Added, Inserted, Modified or Deleted from the original scheme.
Any
number of updates may be made and the Centre Line coordinates recomputed
and restored.


As
the Centre line values (Coordinates and Chainages) are computed they are
stored on a user defined Horizontal Alignment File. Simultaneously, the
centre line point values are displayed on the SURPAC
printer emulation screen. From this screen, the output may be sent to
the current Printer, to an ASCII file, or to the Clipboard.


Setting
out data for Centre Line points may be computed and printed via the Setting
Out Data Sheets.


The
user may select to determine centre line values, or offset values on either side
of the centre line.
Offset
lines are useful when curvilinear boundaries are required along an existing, or
proposed road/rail route.


Computed Points may be :

Converted
to a User defined SURPAC Coordinate File,


Plotted
on a User defined SURPAC CAD Plot Sheet, 

Combined
with SURPAC Vertical Curve Data for determining Section profiles, 

Used
to generate Centre Line Setting Out Field Sheets. 

Vertical Curve Alignment and Section Formation Creation

This
programme provides for the generation of the Design Crosssection formation
data along a road, or a railway route. This data generation is wholly
dependent upon the entered design criteria.


After
entry of the required criteria, the Design Crosssection formation data are
computed for each section and stored in a User defined
Vertical Curve Alignment File. This information may be used by :

The Cross Section Creation and Plotting, 

The programme for the plotting of Cross sections, 

The Longitudinal Section Creation and Plotting
for plotting Longitudinal sections, 

and the Sectional Volumes and ToePeg Calculation
programme for calculating sectional volumes, MassHaul volumes and
ToePeg distances for batter board placement.



The
initial design criteria required by the programme are the design data
for the vertical curves along the proposed route. For each
Vertical Curve, the required input data are
:

The
Intersection Point Chainage 

The Intersection Point
Elevation 

the
Length of the Vertical Curve.



From this information, the programme will compute the parabolic vertical
curve parameters, the Start and End chainages of the curves and the
gradients of the straights connecting the curves.


Any
vertical curve may be defined as having a Curve Length = 0. This is
interpreted as being a "kink", or bend point along the centre
line, and no parabolic curve is computed. The two line gradients will
intersect at the defined Chainage and at the defined Elevation.


The defined point may merely be a chosen point along a gradient,
i.e. the incoming and outgoing gradients may be the same. This is
useful for including "odd" chainage points that may be required
for Cross Section and/or Long Section plotting.


All
vertical curve data should be entered to cover the total length of the
route under consideration. The design Centre Line elevations, at the
designated chainage interval, are then computed.


After
the Centre Line elevations have been computed, design data for the Section Formations
are entered, if these are required. If the
formation design criteria are constant along the entire route, then a single
set of input data will be sufficient. If there are variations, such as the
superelevation changing from curve to curve, then separate design data must
be entered section by section.

The
elements required for the calculation of the design formations are :


The
start and end chainages of the section, or route,


The
median width and slopes,


The
straight to curve development lengths and ratios,


The
curve widening within the curve, if required,


The
Carriage Way crossfalls and superelevations,


The
Carriage Way widths,


The kerb heights and slopes


The
pavement (shoulder) widths and slopes,


Any
auxiliary Carriage Way widening along the straights.


The programme makes allowance for the above mentioned design elements for the
formation Cross sections. These exclude the batter slopes and side drains,
which are defined at the Crosssection plotting stage, when using the Cross Section Creation and Plotting programme, or the volume calculation stage when using the Sectional
Volumes and ToePeg Calculation programme.


Once
all section design data have been entered, the design formations for each
section are also stored on the current Vertical Alignment File .


