File Name: mdnbw01.cri, mdnbw02.cri ...

Reference Standard No. : 854.01 854.02

Required Definition Files: standard

The median barrier wall criteria provides for drawing of "Jersey" style concrete barrier walls separating the two shape clusters. This criteria type is currently capable of three distinct configurations.

It can be used with or without shoulder criteria on either side of the median.

When the 'centered' location of the wall is established, the criteria will determine if the defined wall base width is identical to the gap between the clusters. If the gap is wider than the wall, the template or shoulder on each side will be extended to intersect the sides of the wall. The subgrade earthwork lines underneath the templates or shoulders will also be extended.

User Defined Variables

"MBW01 CONFIG"
Specifies the desired configuration type.
Valid definitions are 0, 1 or 2.

• 0 When defined as zero, the criteria will draw a single barrier wall centered between the two shape clusters. Note that the point of center is dependent on the usage of shoulder criteria. I.E. If shoulder criteria was included on one side of the median, the wall will be centered between the shoulder point of that side and the edge of template on the other side. If shoulder criteria was included on both sides of the median, the wall will be centered between the two shoulder points. This allows for a considerable margin of error on the part of the designer in setting shapes and defining shoulder configurations.
• 1 Configuration type 1 is to be used only when the two shape clusters share the same pgl offset, in other words the clusters are adjoining. The criteria will draw a single barrier wall at the horizontal location of the 'joint' between the two clusters. The designer should note that when the elevation at the edge of the two shape clusters are not the same, the wall will be placed entirely on the lower cluster. Therefore the designer should make allowance for this condition if necessary.
• 2 When defined as two, the criteria will draw two single faced barrier walls in the median at the edge of each template or shoulder point, if shoulder criteria was included. If the median width will not accommodate dual walls, one wall is drawn in the same fashion as configuration type 0. The treatment of the gap between the two walls is dependent on the definition of user defined variable "MBW01 DUAL WALL GAP"

"MBW01 DUAL WALL GAP"
This variable specifies the desired treatment of the gap between two barrier walls when using configuration type 2.
Valid definitions are 0, 1 or 2.

• 0 When defined as zero, criteria will leave the gap open.
• 1 When defined as one, criteria will effectively fill the gap with dirt by drawing a finished grade line from the inside top of the left wall to the inside top of the right wall.
• 2 When defined as two, criteria will draw a concrete cover over the top of the gap.

  Default definition = 2.

"MBW01 GAP SLOPE"
Define as 0 when concrete cover between dual walls is to be flat, with variable height wall on low side.

"MBW01 TOP WIDTH"
Defined as the width of the wall at the top. Specified in inches or meters.
Default definition is 6 inches or 0.15 meters.

"MBW01 BOTTOM WIDTH"
Defined as the width of the base of the wall at the subgrade, in inches or meters.
Default definition is 30 inches or 0.76 meters

"MBW01 HEIGHT"
Defined as the desired height of the wall, measured from vertically from finished grade. Specify as inches or meters.
Default definition is 32 inches or 0.81 meters

"MBW01 KEYIN DEPTH"
Specifies the depth at which the wall will be 'keyed' into the pavement. Defined as inches or meters.
Default definition is 2 inches or .05 meters.

There are distinct differences between the three configurations available for median barrier walls, and because of the magnitude of these differences, little of the actual criteria 'code' is shared by the different configurations. Therefore the following methodology summaries are separated according to configuration type.

Configuration 0
The main difference between type 0 and the other two types is it's provision for locating the wall in the center of the gap and extending the left and right templates or shoulders into the wall. This is accomplished by first marking points at the edge of templates or shoulders on both sides of the median, on both finished and subgrade. These points remain constant and are used to determine the original width of the gap between the clusters.
The internal variable _d_PreviousCriteriaType is used in conjunction with _d_TM_PavementSlope or _d_SH_ShoulderSlope to set the variables _d_MBW_SlopeAtLeftOrigin , _d_MBW_LeftOriginSubgradeSlope, _d_MBW_SlopeAtRightOrigin and _d_MBW_RightOriginSubgradeSlope.

Configuration 1
The type 1 concept is based on the assumption that no shoulders will be involved and that the two shape clusters will always be horizontally congruent. If the elevations at the origin points are not the same, the wall is drawn entirely on the surface of the lower cluster. The finished grade and subgrade is connected vertically between the two clusters. The programmer should note that these 'vertical' connections are made with two slightly sloped segments to avoid the use of truly vertical elements.