Widening and Rehabilitation Projects

	A wide variety of widening and rehabilitation projects are designed today, with the projects 
as basic as simple widening or perhaps just a mill and overlay, to as complex as overlay, widening, 
pavement slope correction, and safety improvements on the slopes.  Most of these projects can be 
categorized into six basic types.  These include:

1.	Widening only - In this type of project, no work is done on the mainline roadway, the edge of 
pavement is often saw cut for adhesion of new lane or shoulder, then additional lane and / or 
shoulder is constructed.  When an additional lane is added, it is constructed at the same slope as the 
adjoining mainline roadway.  

2.	Widening only - In this type of project, no work is done on the mainline roadway, the edge of 
pavement is often saw cut for adhesion of new lane or shoulder, then additional lane and / or 
shoulder is constructed.  When an additional lane is added, it is constructed at the slope specified by 
the shaping.

3.	Mill and Overlay - In this type of project, a constant depth is milled and an overlay is added.  
The results can be no change in the centerline profile, or a constant offset of the existing profile.  For 
example, a 3 inch overlay with 3 inch wearing course would result in no change to the centerline 
profile.  However, a three inch milling with six inch overlay would result in a three inch raise in the 
profile.  This type of project assumes that no slope correction is done to the existing roadway.

4.	Mill and Overlay With Widening (Slope Matching Adjoining Lane)- In this type of project, a 
constant depth is milled and an overlay is added.  The results can be no change in the centerline 
profile, or a constant offset of the existing profile.  For example, a 3 inch overlay with 3 inch 
wearing course would result in no change to the centerline profile.  However, a three inch milling 
with six inch overlay would result in a three inch raise in the profile.  This type of project assumes 
that no slope correction is done to the existing roadway.  Widening or turn lane additions are 
accomplished via an "element in dgn."

5.	Mill and Overlay With Widening (Widening Slope Based on Shapes)- In this type of project, 
a constant depth is milled and an overlay is added.  The results can be no change in the centerline 
profile, or a constant offset of the existing profile.  For example, a 3 inch overlay with 3 inch 
wearing course would result in no change to the centerline profile.  However, a three inch milling 
with six inch overlay would result in a three inch raise in the profile.  This type of project assumes 
that no slope correction is done to the existing roadway.  Widening or turn lane additions are 
accomplished via an "element in dgn."

6.	The most extensive rehabilitation projects are those that require slope correction.  In these 
cases, a minimum overlay is calculated, and the slopes of the shaping are applied.  However, the 
profile at which the shapes are created is not utilized, as the minimum thickness is the control.

Let's review the general procedure and the criteria utilized to generate cross sections for these 
projects.


Case 1 - Widening  (Same Slope as Adjoining Lane)

	In this type of widening project, a dummy shape is required.  Its slope and profile are not 
utilized, as the existing ground is the control.  However, at this time, in order to draw a cross section, 
GEOPAK does require a minimum of one dependent shape.

	The procedure is as follows:

1.	Create a single, dependent shape the length of the project.  Quite often, the alignment is the 
inplace centerline of the existing roadway, and several pieces of criteria can utilize this 
information.  The profile can be a flat line, with a minimum of two VPIs, once again the length 
of the project.

2.	The criteria is set up so that marked points required for subsequent standard criteria are included.  
Therefore, standard shoulders, ditches, etc. can be utilized for safety improvements outside the 
roadway, if desired.

3.	If the inplace pavement, shoulders, etc. is to be drawn, utilize the standard inplace criteria 
(inplace 1-12) specifying the correct dimensions for each variable.

4.	For the widening criteria, utilize one of the following criteria:

	*	rehab1 - This criteria will utilize an "element in dgn" in order to draw the adjacent lane.  If no 
"element in dgn" if found, no widening will be drawn.  The widening begins at the edge of 
the shaping (i.e., px1).

	*	rehab2 - In this criteria, a standard width will be utilized to widen all sections where the 
criteria is applied.  The widening begins at the edge of the shaping (i.e., px1).

	*	rehab3 - This criteria is a modified combination of rehab1 and rehab2.  In this case, the 
criteria will search for an "element in dgn" for the widening distance.  If none is found, then 
it will utilize the default "widen distance" to widen each section.  The widening begins at the 
edge of the shaping (i.e., px1).

	*	rehab4 - In this code, the criteria will search for an "element in dgn" for the widening 
distance.  If not is found, then it will utilize the default "widen distance" to widen each 
section.  However, this code uses an "element in dgn" to determine the saw cutting or edge of 
roadway placement.

5.	This criteria should be included on both side slope right and side slope left if widening is on both 
sides of the roadway throughout the project.

Case 2 - Widening  (Slope Based on Shaping)

	In this type of rehabilitation project, a shape is required.  Its shape cluster baseline and profile are 
not utilized, as the existing ground is the control.  However, the placement of the shape and the slope 
are utilized, so this information must be relevant to the project.  The easiest method to accomplish 
this is by utilizing a tie, i.e., the horizontal distance from the shape cluster baseline to the edge of the 
shape.  Normally, the tie is the distance from the shape cluster baseline to the profile grade line, 
however, since we are not utilizing the profile, it is immaterial where the profile grade line is located.  
For example, the inside edge of the shape must be drawn to coincide with the outside edge of the 
inplace roadway or the saw cutting line.  The distance from the centerline to this edge would be the 
tie value.  GEOPAK will seek this edge of the shape, drop a perpendicular down (or up as the case 
may be) to existing ground, then project the slope of the shaping onto the cross section, similar to a 
copy parallel command of the shaped pavement.  As there is only one shape, it must be dependent.  

	The procedure is as follows:

1.	Draw shapes at the desired cross slope and the correct xy location in the plan view file.  Any 
alignment and profile which intersect the pattern line or the cross section may be utilized, 
however, quite often, the alignment is the inplace centerline of the existing roadway, and the 
centerline existing ground profile is used.  However, this is not required.  The profile can be a 
flat line, with a minimum of two VPIs, once again the length of the project.

2.	The criteria is set up so that marked points required for subsequent standard criteria are included.  
Therefore, standard shoulders, ditches, etc. can be utilized for safety improvements outside the 
roadway, if desired.

3.	If the inplace pavement, shoulders, etc. are to be drawn for display purposes, utilize the standard 
inplace criteria (inplace 1-12) specifying the correct dimensions for each variable.

4.	For the widening criteria, utilize the following criteria:

	*	rehab5 - This criteria will utilize the shape drawn in item 1.  If no shape is found, then no 
widening will be drawn.

5.	This criteria should be included on both side slope right and side slope left if widening is on both 
sides of the roadway throughout the project.

Case 3 - Mill and Overlay  (No Widening)

	In mill and overlay projects, a dummy shape is required.  Its slope and profile are not utilized, as 
the existing ground is the control.  However, at this time, in order to draw a cross section, GEOPAK 
does require a minimum of one dependent shape.

	The procedure is as follows:

1.	Create a single, dependent shape (unless rehab8 is being utilized) the length of the project.  Quite 
often, the alignment is the inplace centerline of the existing roadway, and several pieces of 
criteria can utilize this information.  The profile can be a flat line, with a minimum of two VPIs, 
once again the length of the project.

2.	The criteria is set up so that marked points required for subsequent standard criteria are included.  
Therefore, standard shoulders, ditches, etc. can be utilized for safety improvements outside the 
roadway, if desired.

3.	If the inplace pavement, shoulders, etc. is to be drawn, utilize the standard inplace criteria 
(inplace 1-12) specifying the correct dimensions for each variable.

4.	For the mill and overlay criteria, utilize one of the following criteria:

	*	rehab6 - This criteria will parallel existing ground offset by a specified amount which should 
be resultant distance of the mill and overlay.  A positive value assumes you are above the 
existing roadway, a negative assumes you are milling off more than you are overlaying. This 
criteria assumes a fixed width mill and overlay.

	*	rehab7 - This criteria will parallel existing ground offset by a specified amount which should 
be resultant distance of the mill and overlay.  A positive value assumes you are above the 
existing roadway, a negative assumes you are milling off more than you are overlaying. This 
criteria utilizes an "element in dgn" for the width of the  mill and overlay.

	*	rehab8 - This criteria will parallel existing ground offset by a specified amount which should 
be resultant distance of the mill and overlay.  A positive value assumes you are above the 
existing roadway, a negative assumes you are milling off more than you are overlaying.  
Unlike the other mill and overlay criteria, this criteria utilizes the width of the slope mapping 
as the width of the overlay.  In order to use this criteria, shapes must be placed on both sides 
of the roadway.

5.	These criteria should be included on both side slope right and side slope left throughout the 
project.

Case 4 - Mill, Overlay and Widening  (Same Slope as Adjoining Lane)

	In this type of widening project, a dummy shape is required for each section to mill and overlay 
as GEOPAK does require a minimum of one dependent shape in order to draw criteria.  Widening 
and turn lane additions are specified by elements in the plan view file.  For the mill and overlay 
shape, its slope and profile are not utilized, as the existing ground is the control.

	The procedure is as follows:

1.	Create a single, dependent shape the length of the project.  Quite often, the alignment is the 
inplace centerline of the existing roadway, and several piece of criteria will utilize this 
information.  The profile can be a flat line, with a minimum of two VPIs, once again the length 
of the project.

2.	The criteria is set up so that marked points required for subsequent standard criteria are included.  
Therefore, standard shoulders, ditches, etc. can be utilized for safety improvements outside the 
roadway, if desired.

3.	If the inplace pavement, shoulders, etc. is to be drawn, utilize the standard inplace criteria 
(inplace 1-12) specifying the correct dimensions for each variable.

4.	For the mill, overlay and widening criteria, utilize one of the following criteria:

	*	rehab9 - This criteria will measure (at the xpgl) from existing ground by a specified amount 
which should be the resultant distance of the mill and overlay.  A positive value assumes you 
are above the existing roadway, a negative assumes you are milling off more than you are 
overlaying. This criteria assumes a fixed width mill and overlay.  If an "element in dgn" is 
found, it will be utilized in drawing the widening.  If none is found, only the mill and overlay 
will be drawn.

	*	rehab10 - This criteria will measure (at the xpgl) from existing ground by a specified amount 
which should be the resultant distance of the mill and overlay.  A positive value assumes you 
are above the existing roadway, a negative assumes you are milling off more than you are 
overlaying.  This criteria utilizes an "element in dgn" for the width of the mill and overlay.  If 
a "widening element in dgn" is found, it will be utilized to draw the widening.  If none is 
found, only the mill and overlay will be drawn.  Note the element symbology of the edge of 
milling and edge of widening should be unique.

	*	rehab11 - This criteria will measure (at the xpgl) from existing ground by a specified amount 
which should be the resultant distance of the mill and overlay.  A positive value assumes you 
are above the existing roadway, a negative assumes you are milling off more than you are 
overlaying.  Unlike the other mill and overlay criteria, this criteria utilizes the width of the 
first shape (done with auto shape or the Shape Maker window) as the width of the overlay.  
On any section where a second shape is encountered on a side, it will utilize the shape as 
widening.  In order to use this criteria, shapes must be placed on both sides of the roadway.

5.	These criteria should be included on both side slope right and side slope left throughout the 
project.

Case  5- Slope Correction Projects 

	The most complex of rehabilitation projects is one which involves slope correction and a 
minimum overlay depth.  In these projects, separate criteria cannot be run on side slope left and 
right, as you have to determine the minimum point of the entire roadway to determine where to 
measure the minimum depth.  Therefore the criteria will be run on one side, but will draw the entire 
section.  The slope correction is determined byt he slopes of the shapes, however the shape cluster 
baseline and profile are not utilized.  Once the minimum point is determined (and text placed to 
identify its position for the designer) the correct slopes are moved to the minimum point, similar to a 
copy parallel command.  A B-spline profile is created at centerline with this approach.  The user has 
the option to create a proposed profile from these cross sections, then utilize the profile in the 
horizontal alignment generator if vertical curves are required.  In this case, all vertical curves must 
be fit above the B-spline as to not affect the minimum depth.  The adjusted profile could then be 
utilized to run another set of sections reflecting the profile and its vertical curves.

The procedure is as follows:

1.	Utilizing the inplace centerline alignment and a dummy profile, create shapes with the desired 
cross slopes.  Note the actual elevation of the profile will not be utilized as the pavement will be 
raised or lowered to fit the minimum overlay depth.

2.	Utilize the following criteria from one side only.

	*	rehab 12

3.	The criteria is set up so that marked points required for subsequent standard criteria are included.  
Therefore, standard shoulders, ditches, etc. can be utilized for safety improvements outside the 
roadway, if desired.

4.	Once the sections are complete, a B-spline profile of the centerline may be generated.  Utilize the 
proposed profile from cross section feature.

5.	If desired, the profile may be loaded via the vertical alignment generator.  Vertical curves may be 
fitted, keeping in mind that the profile you have is the minimum.  You do not want an elevation 
less than the B-spline.  Any adjustments to fit vertical curves will raise the profile, thus you will 
have more than the minimum overlay depth.  The minimum overlay depth vs. vertical curves is a 
project or organization specific decision, as GEOPAK can generate profiles and cross sections 
via either method.

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