ce 321 final report

The Pennsylvania State University

Department of Civil Engineering

CE 321: Highway EngineeringDr. Eric Donnell, ProfessorJung Yeol Hong, TA.

Preliminary Rural Collector Design,Connecting PA SR 1025 and North Road

Fall 2014

Section 001

Zahin Chowdhury

Due Date: November 21, 2014Table of Contents

1. Introduction31. Digital Terrain Modeling31. Horizontal Alignment31. Vertical Alignment41. Cross Section and Earth Work51. Comparison of Alignments61. Conclusion7Appendix A8Appendix B10Appendix C15

1. IntroductionA need is expressed for a 2-lane rural collector to connect PA SR 1025 near Tobymines with North Road near Centerville. The objective of the project is to design two alternatives for this collector. One road is to pass between the state forest and historic property to the East, while the other alternative is to go around the state forest to the west. Both alternatives are designed for an average daily traffic of 1500 vehicles per day and a design speed of 45 mph. The designs are to be in accordance with the AASHTO Green Book. Other objectives of the designs are to minimize impact on the state forest, existing communities, and historic property. 1. Digital Terrain ModelingThe objective of the Digital Terrain Modeling (DTM) section of the project was to import a contour layer with existing features containing information regarding the landscape surrounding the two roads to be connected. AutoCAD Civil 3D easily imported these files to provide a map on which to work. Existing features included local roads, homes, rivers, forests, historical areas, and contour lines.The objective was met by opening a given layout of contours and landscape features. The imported file was saved as a surface. The contours were then labeled and the rest of the existing features were inserted as a block. No major difficulties were encountered with the design or software.

1. Horizontal AlignmentThe purpose of the Horizontal Alignment section was to lay out the two proposed alternatives for collector roads while keeping costs to a minimum and safety to a maximum. Centerlines for the two roads were created to define the main pathway.Existing terrain conditions dictated the preliminary design criteria. The alignments were designed around contours to avoid unnecessary excavation and filling as much as possible. The historical district, community areas, and state forest were also avoided as much as possible. Design criteria from the Green Book are listed in Tables 1 and 2 below. All of the mentioned criteria were met by laying out a preliminary design and adjusting as necessary.

Design Criteria

emax8%Clear zone width10'

Traveled way width24'Maximum grade8%

Shoulder width8'Minimum grade0.50%

Table 1. Green Book Design Criteria

Safety Criteria

Max. Grade within 200' of an intersection3%

Minimum tangent length200'

Minimum curve length100'

Table 2. Safety and Operations Criteria

The process of creating a horizontal alignment involves 4 steps as follows.

1) Setting the minimum radius for curves.2) Drawing the alignment using the Tangent-Tangent (with curves) command. 3) Labeling the alignment stations.4) Reworking the alignment to fit the design criteria.

The East alternative includes 3 curves and 4 tangents that all meet the minimum length requirements set by the design criteria. The East alignment does not impact any state forest or historical district. The West alternative includes 5 curves and 6 tangents that all meet the minimum length requirements set by the design criteria. The West alternative does not impact any historical districts, and impact on the state forest is minimal. The West alignment is significantly shorter and straighter than the East alignment.

1. Vertical AlignmentThe purpose of this section is to create a vertical profile of the horizontal alignments. The profile clearly shows the variations in elevation along the alignment as well as how the road will intersect the existing ground, laying the foundation for the earthwork calculations to come. The topographic map used earlier was used in this section. Design criteria can be found in tables 3 and 4. Steps for completing this section were as follows.

1) Creating an existing ground profile.2) Drawing in tangents with curves to minimize earthwork.3) Reworking the alignment to meet design criteria

Design Criteria

Minimum curve length100'

Maximum grade8%

Minimum grade0.5%

Maximum grade within 200' of an intersection3%

Minimum clearance over streams5'

Table 3. Vertical alignment design criteria

Curve K Values

Crest61

Sag79

Table 4. Curve K Values

One of the objectives of this step was to minimize the volume of cut and fill needed. This was done by contouring curves and tangents as close to the existing ground line as possible. Due to design constraints and mountainous terrain, however, several massive cuts and fills were necessary at points.The East alignment for the most part falls within the design criteria, most of the land is flat and there is smaller incremental changes in elevation compared to the west alignment.The West alignment however requires massive cuts and fills to meet the design criteria set up by Table 3. The terrain has more mountainous terrain and at some points in the see great elevation changes between stations.

Cross Section and Earth WorkThe following steps were taken to create a sampling of cross sections from the proposed alignments. Design criteria for these steps is listed in Table 5 below.

1) Cross section dimensions were established.2) A template assembly was created for a corridor.3) A corridor was created from the assembly. 4) Cross sections were taken at the beginning stations, end stations, and at every 2000 interval.5) Cut and fill areas were calculated from the sample cross sections.6) Total alignment area was calculated.

Cross Section Dimensions

Traveled WayWidth12' lanes

Normal Crown2%

ShoulderWidth8'

Slope4%

Clear ZoneWidth10'

Slope 4%

Ditch foreslope and backslope (x:y)2:1

Table 5. Cross section dimensions

The footprint of each alternative was able to be seen through the creation of the corridor. This step was essential in earthwork and cost estimations. It also displayed possible unforeseen impacts on state forest and historic districts. AutoCADs area command was used to calculate the exact footprints and earthwork of each alignment. Results can be found in Table 6 below.

Land FeatureImpact of East Alternative (Acres)Impact of West Alternative (Acres)

Forest6.0158.2

Undeveloped31.66148.1

Historic01.38

Total37.66207.68

Table 6. Impact of East and West alternatives

Comparison of Alignments4 main criteria were used in the cost estimation. These included severity of crashes, earthwork requirements, pavement cost, and right of way acquisition costs. A breakdown of each of these costs can be seen calculated in table 7 below. The East alignment proved to be the far superior option considering the cost breakdowns by a factor of 10. The East alignment is also less curvy, both horizontally and vertically, making it the safer option.

Cost Estimations

East AlignmentWest Alignment

Severity $ 2,183,482.76$2,216,656.93

Earthwork$ 49,565,824.40$2,518,278,463.86

Pavement$2,127,073.63$1,943,576.25

Right of Way Acquisition$1,290,111.60$12,738,631.80

Total$55,166,492.40$2,535,177,328.84

Table 7. Alignment cost estimations

Conclusion

Taking all factors into consideration primarily Earthwork cost the East alignment should be chosen. Earthwork for the East alignment will cost upwards of $2.5 billion, an absurd amount to spend. The East Alignment is a fifth of the cost of the West Alignment and therefore should be chosen.

Appendix A(Horizontal Curve Reports)The horizontal curve report generation function in Civil 3D does not work in this version. Instead of generating a report like you do for the Vertical Curves, copy the information from the grid view under Edit Alignment Geometry. Select the alignment you want to generate a report for Right click and select Edit Alignment Geometry Click the Alignment Grid View icon as shown below

Right click in any cell and select Copy All Paste table to a new Excel file You can delete the following columns Start Point End Point Center Point Pass Through Point Direction at Through Point1 Direction at Through Point2 Attainment Method Curve Group Index Curve Group Sub-Entity Index Pi Point Use the remaining table as your Horizontal Curve Report Do this for East and West, make sure they are labeled and include them in this appendix

Appendix BVertical Alignment: East Profile Description: Station Range: Start: 10+00.00, End: 170+61.83 Vertical Curve Information:(crest curve) PVC Station:11+98.39Elevation:1,327.522'

PVI Station:13+60.49Elevation:1,330.259'

PVT Station:15+22.58Elevation:1,329.416'

High Point:14+46.24Elevation:1,329.614'

Grade in:1.69%Grade out:-0.52%

Change:2.21%K:146.803'

Curve Length:324.184'Curve Radius14,680.294'

Passing Distance:862.345'Stopping Distance:463.037'

Vertical Curve Information:(crest curve) PVC Station:25+29.40Elevation:1,324.180'




Grade in:-0.52%Grade out:-1.96%

Change:1.44%K:76.383'


Passing Distance:1,128.357'Stopping Distance:516.306'

Vertical Curve Information:(sag curve) PVC Station:37+72.59Elevation:1,300.597'



Low Point:38+69.82Elevation:1,299.054'


Change:0.75%K:129.948'


Headlight Distance:





Grade in:-1.21%Grade out:0.49%

Change:1.70%K:88.311'


Headlight Distance:






Change:1.93%K:77.878'







Grade in:-1.44%Grade out:1.46%

Change:2.90%K:86.134'


Headlight Distance:486.462'





Grade in:1.46%Grade out:0.56%

Change:0.90%K:68.679'


Passing Distance:1,746.329'Stopping Distance:768.166'






Change:0.09%K:117.216'


Headlight Distance:






Change:7.15%K:84.503'








Change:5.10%K:71.918'



Vertical Alignment: West Profile Description: Station Range: Start: 10+00.00, End: 156+68.26 Vertical Curve Information:(sag curve) PVC Station:16+47.38Elevation:1,343.568'





Change:4.81%K:79.688'








Change:0.09%K:73.930'


Passing Distance:16,681.595'Stopping Distance:7,171.149'






Change:12.15%K:62.476'








Change:3.30%K:62.500'








Change:5.04%K:67.072'



Appendix CSpreadsheets for cost estimation and earthwork:Safety FunctionSafety CostPavement CostRight of Way CostEarthwork Table(You will have a set of these for the EAST and another set for the WEST, make sure all are labeled clearly)

List of Drawing

East Alternative Horizontal Alignment 1 of 7West Alternative Horizontal Alignment 2 of 7Typical Cross Section 3 of 7Plan/Profile East Alternative 4 of 7East Alternative Cross Section5 of 7Plan/Profile West Alternative6 of 7West Alternative Cross Section 7 of 7

ce 321 final report

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