A.02.12 Performance Work Statement Appendicies.pdf

Pipe Elevation Adhere to minimum cover requirements and attempt to outlet pipes at the elevation of the natural ground, where possible. This will eliminate the need for long “tail ditches” at pipe outlets, which are an on-going source of maintenance and erosion. More information on pipe elevation can be found in the “Shallow Crosspipe Installation” Tech Bulletin.

Pipe Length and Angle On roads with linear grade, install crosspipes at an angle, to line up with natural drainage patterns and to more efficiently move water through the road (Figure 1). This has advantages over installing pipes straight across a road:

Reduces erosion around pipe inlet and outlet that results when water “turns” to enter or exit the pipe.

Pipe efficiency is increased when water does not have to turn 90° to enter the inlet.

Traffic loading on the pipe is decreased, since only one vehicle tire at a time is directly over the pipe.

Angled pipes tend to “self clean,” and collect less sediment and debris in the pipe and at the inlet.

Bedding/Fill Material When selecting a material for use as bedding and fill around a crosspipe, compaction and frost action are the two most important concerns. When possible, use the material that is excavated out of the pipe trench. However, if the material contains a lot of large rocks it will not compact properly and new material must be imported. Keep in mind the following when selecting a bedding material:

Photo 1. A plastic crosspipe is shown during installation. Notice the pipe bedding material, endwall, and stone at outlet.

YES NO

bank erosion bank erosion ditch flow

Figure 1. The crosspipe shown in black is improperly aligned straight across the road. The red pipe indicates a better pipe placement that will carry more water, cause less erosion, and will better resist crushing.

Crosspipe Installation: This technical bulletin deals with techniques for the installation of traditional road drainage culverts (not stream pipes). Traditional crosspipes rely on road surface elevation to determine pipe depth. A related technical bulletin includes details of a “Shallow Crosspipe Installation.”

The publishers of this publication gratefully acknowledge the financial support of the PA State Conservation Commission. For additional information or assistance, contact: Center for Dirt & Gravel Roads Studies, Penn State University, 215 Transportation Research Building, University Park, PA 16802 (Toll-Free Phone: 1-866-668-6683, Fax: 814-863-6787, Email: dirtandgravel@psu.edu). Additional copies available on our website at:

https://www.dirtandgravel.psu.edu. © 2019 All rights reserved.

Imported bedding and fill should be as similar as possible to existing road material. This will insure that the entire road will react in the same way to cycles of freeze and thaw.

Bedding and fill material must be moist to achieve the best compaction. Compaction is crucial beneath, beside, and above the pipe to provide proper pipe support and avoid pipe flexing. A ribbed pipe gets its structural strength when properly compacted into the road bed.

Some common fill materials include crushed bank run gravel, shale, and PENNDOT 2RC aggregate.

Other Considerations When raising the road, fill should be placed and compacted prior to pipe installation. After road fill is in place, excavate the pipe trench and proceed with installation.

Ensure that all crosspipes have effective fall (shoot for 2%+ and no less than 1%).

Pipes require headwalls and endwalls to reduce erosion, improve function, and protect the pipe inlet/outlet.

Drop-inlets (grates like on storm sewers) are not recommended for use on unpaved roads.

Crosspipe Installation

1/2019 Appendix A.

mailto:dirtandgravel@psu.edu

A

B

C

D

E

Crosspipe Installation

1. Excavate Pipe Trench: Trench should be wide enough to fit compaction device (shown in “D”) on both sides of pipe. Trench depth will depend on outlet elevation. Ideally, outlet pipe at natural ground elevation to eliminate the need for a tail-ditch.

Bottom of pipe inlet should be at the same elevation as the upslope ditch. Use a level to ensure fall in the pipe trench (see photo A). If needed, use fill to adjust the elevation of the upslope ditch and the road surface to ensure pipe has fall and proper cover. Consider a Shallow Crosspipe where appropriate.

2. Place Pipe Bedding: Once the trench is complete, some bedding material may be needed. Use bedding to smooth trench bottom for pipe support and to achieve proper fall. Some shovel and rake work is usually required to spread bedding evenly. Use a level to find any uneven spots and double-check slope (See photo B). Compact bedding material before pipe placement.

3. Place Pipe in Trench: Place and align first section of pipe in trench. Pipe inlet should be located in the existing ditch line, with room between the pipe and the bank for a headwall. Inlets that are too close to the road pose traffic hazards. Inlets that are to far off the road can cause unnecessary bank erosion.

Align additional pipe sections and secure together with collars or by seating the attached gasket. Look for uniform support in the pipe bedding. Voids under the pipe will cause sagging upon compaction. Headwalls and endwalls can be constructed at this time or after the pipe installation is complete. Either way, the fill behind headwalls and endwalls must be placed and compacted in shallow lifts (3 min) and should tie the wall into the road bed.

4. Place and compact fill material around pipe: Place the first lift of fill material around pipe until approximately 8” of material is on each side of pipe. Pipe must be held in place so fill material does not move or lift pipe (See photo C). Use an upright tamper to compact fill on both sides of pipe. Compaction of the first layer of fill material is crucial because it fills voids and packs material around the base of the pipe for support (See photo D).

The importance of compaction cannot be overstated! HDPE pipes (plastic pipes) get their structural strength from the material compacted tightly around them and into the ribs. Care should be taken not to damage the pipe with the foot of the tamper while compacting. Continue to fill and compact in stages, or lifts, placing approximately 8” of fill before compaction. If too much fill is placed at once, proper compaction cannot be achieved. Continue to fill and compact overtop of pipe (See photo E). Be sure to provide adequate compacted cover over the pipe. Adequate cover varies with pipe size and construction.

Most plastic pipes, up to 48” in diameter, require a minimum of 12” of compacted cover.

5. Never allow truck traffic over partially installed crosspipes without at least 12” of compacted cover for protection.

The University is committed to equal access to programs, facilities, admission and employment for all persons. It is the policy of the University to maintain an environment free of harassment and free of discrimination against any person because of age, race, color, ancestry, national origin, religion, creed, service in the uniformed services (as defined in state and federal law), veteran status, sex, sexual orientation, marital or family status, pregnancy, pregnancy-related conditions, physical or mental disability, gender, perceived gender, gender identity, genetic information or political ideas. Discriminatory conduct and harassment, as well as sexual misconduct and relationship violence, violates the dignity of individuals, impedes the realization of the University's educational mission, and will not be tolerated. Direct all inquiries regarding the nondiscrimination policy to the Affirmative Action Office, The Pennsylvania State University, 328 Boucke Building, University Park, PA 16802-5901, Email: aao@psu.edu, Tel (814) 863-0471

Headwalls & Endwalls

The publishers of this publication gratefully acknowledge the financial support of the PA State Conservation Commission. For additional information or assistance, contact: Center for Dirt & Gravel Roads Studies, Penn State University, 215 Transportation Research Building, University Park, PA 16802 (Toll-Free Phone: 1-866-668-6683, Fax: 814-863-6787, Email: dirtandgravel@psu.edu). Additional copies available on our website at:

https://www.dirtandgravel.psu.edu. © 2019 All rights reserved.

Headwalls and Endwalls can be made with a variety of materials including native stone (a), boulders (b), poured concrete (c), or pre-cast concrete (d).

PURPOSES

Headwalls and endwalls support the road and protect the ends of the pipe. Properly constructed headwalls and endwalls improve pipe efficiency while reducing erosion around pipe installations.

BENEFITS OF HEADWALLS AND ENDWALLS

• Provide a low-cost, long-lasting solution to erosion problems at pipe openings.

• Prevent flowing water from damaging the road structure.

• Provide structural support for the road shoulder.

• Increase the efficiency of pipes by directing flow and reducing turbulence.

• Headwalls can reduce flow by-pass of the pipe, or “piping.”

• Visually identify pipe openings and protect them from damage by traffic and maintenance equipment.

NECESSITY FOR PROTECTION AT PIPE OPENINGS

It is necessary to protect pipe openings for several reasons:

• Water is turbulent when it changes direction or velocity, increasing its erosive potential.

• Water accelerates as it passes through a pipe, creating the need to stabilize surrounding soil to prevent erosion.

• Erosion of unprotected areas increases sediment pollution and maintenance costs.

• Physical support for the road and banks may be necessary at pipe openings.

• Headwalls and endwalls help guard against crushed pipes.

MATERIALS

Headwalls and endwalls can be built with many different materials.

Several factors influence the choice of materials, including: local availability, skill and time required for construction, durability, and cost. Materials used in Pennsylvania include *:

• Stackable stone, either collected or purchased

• Rounded rocks and boulders

• Pre-cast concrete and cast-in-place concrete

• Modular masonry products (various sized blocks)

• Modular plastic products (fillable) *Construction techniques using stone is detailed in the Stacked Stone Headwalls technical bulletin.

d headwall endwall endwall

Headwall Or endwall

Headwall or Endwall– An integrated wall located at either end of drainage pipe or a stream crossing structure.

A wall built at a pipe inlet is a headwall. A wall built at a pipe outlet is an endwall.

1/2019

Appendix B.

SHAPE

The shape of a headwall or endwall is important to direct water flow, to support and protect the road and the banks from erosive flow, and to improve drainage efficiency.

Pipe Outlet:

Endwall supports and protects bank.

Pipe Inlet:

Headwall protects bank and directs flow

Pipe

Figure 1: Plan or Bird’s Eye View Figure not drawn to scale.

Headwalls can be built with wing walls to steer flow to the pipe inlet and with bank walls to stabilize steep road banks (see pictures). These structures reduce erosion and the potential for pipe plugging. At the outlet, the endwall supports the road edge and reduces possible undermining of the road structure.

Headwall with angled Wing walls

Pipe Inlet:

Angle-shaped headwall

On roads with linear grade, it is important to plug the road ditch to force ditch flow into the pipe. Water forced to change direction can be very erosive. Erosion at a pipe inlet is not only a pollution source but can cause increased maintenance. Adding angle to a headwall directs, protects, and improves pipe function (Figure 2).

Figure 2: Plan or Bird’s Eye View Figure not drawn to scale.

Pipe Outlet

Pipe

12”

15”Pipe

Road Surface

Figure 3: Longitudinal Section of Pipe Installation.

The headwall and endwall extend 12” above the pipe to ensure proper cover, to support the road, and to improve pipe capacity.

Figure not drawn to scale.

IMPORTANT CONSIDERATIONS:

• Headwalls and endwalls should be built high enough to support the full depth of pipe cover recommended by the manufacture, typically 12” for both plastic and corrugated steel pipe 48” in diameter and smaller (Figure 3).

• It is critically important to anticipate the forces of drainage water under high flow conditions. Drainage structures should be built to protect the road and banks during large storm events. Headwalls and endwalls built to the proper height improve pipe efficiency during very high flows and help prevent flow by-pass, road washouts, and compounding damage caused by pipe failure.

Headwall with Bankwall

The University is committed to equal access to programs, facilities, admission and employment for all persons. It is the policy of the University to maintain an environment free of harassment and free of discrimination against any person because of age, race, color, ancestry, national origin, religion, creed, service in the uniformed services (as defined in state and federal law), veteran status, sex, sexual orientation, marital or family status, pregnancy, pregnancy-related conditions, physical or mental disability, gender, perceived gender, gender identity, genetic information or political ideas. Discriminatory conduct and harassment, as well as sexual misconduct and relationship violence, violates the dignity of individuals, impedes the realization of the University's educational mission, and will not be tolerated. Direct all inquiries regarding the nondiscrimination policy to the Affirmative Action Office, The Pennsylvania State University, 328 Boucke Building, University Park, PA 16802-5901, Email: aao@psu.edu, Tel (814) 863-0471

Location Length (ft.) Culvert # Material Diameter (in.) Length (ft.) Task Materials 1 concrete 18 24 remove existing cluvert, install new 18" x 24' culvert, install new 18" precast concrete headwalls 2 concrete 15 24 remove existing cluvert, install new 18" x 24' culvert, install new 18" precast concrete headwalls 3 concrete 15 24 remove existing cluvert, install new 18" x 24' culvert, install new 18" precast concrete headwalls 4 concrete 15 24 remove existing cluvert, install new 18" x 24' culvert, install new 18" precast concrete headwalls 5 concrete 15 24 remove existing cluvert, install new 18" x 24' culvert, install new 18" precast concrete headwalls 6 concrete 15 24 remove existing cluvert, install new 18" x 24' culvert, install new 18" precast concrete headwalls 7 concrete 15 24 remove existing cluvert, install new 18" x 24' culvert, install new 18" precast concrete headwalls

8A plastic 18 24 flush pipe and remove all debris to allow for proper drainage 8B plastic 18 20 flush pipe and remove all debris to allow for proper drainage 9 plastic 18 24 flush pipe and remove all debris to allow for proper drainage

10 plastic 24 24 flush pipe and remove all debris to allow for proper drainage 11 plastic 18 24 flush pipe and remove all debris to allow for proper drainage 12 concrete 24 24 remove existing cluvert, install new 24" x 24' culvert, install new 24" precast concrete headwalls 1 concrete 18 40 remove existing cluvert, install new 18" x 40' culvert, install new 18" precast concrete headwalls 2 plastic 24 30 flush pipe and remove all debris to allow for proper drainage 3 plastic 18 20 flush pipe and remove all debris to allow for proper drainage 4 plastic 24 24 flush pipe and remove all debris to allow for proper drainage 5 plastic 36 40 flush pipe and remove all debris to allow for proper drainage 6 plastic 30 40 flush pipe and remove all debris to allow for proper drainage 7 concrete 18 20 remove existing cluvert, install new 18" x 20' culvert, install new 18" precast concrete headwalls 1 concrete 18 50 remove existing cluvert, install new 18" x 50' culvert, install new 18" precast concrete headwalls 2 concrete 18 50 remove existing cluvert, install new 18" x 50' culvert, install new 18" precast concrete headwalls 3 concrete 18 50 remove existing cluvert, install new 18" x 50' culvert, install new 18" precast concrete headwalls 4 concrete 18 50 remove existing cluvert, install new 18" x 50' culvert, install new 18" precast concrete headwalls 5 concrete 18 50 remove existing cluvert, install new 18" x 50' culvert, install new 18" precast concrete headwalls 6 concrete 18 50 remove existing cluvert, install new 18" x 50' culvert, install new 18" precast concrete headwalls 7 concrete 18 50 remove existing cluvert, install new 18" x 50' culvert, install new 18" precast concrete headwalls 8 galvanized 18 50 remove existing cluvert, install new 18" x 50' culvert, install new 18" precast concrete headwalls 9 galvanized 18 50 remove existing cluvert, install new 18" x 50' culvert, install new 18" precast concrete headwalls

10 galvanized 18 50 remove existing cluvert, install new 18" x 50' culvert, install new 18" precast concrete headwalls 11 galvanized 36 40 remove existing cluvert, install new 36" x 40' culvert, install new 36" precast concrete headwalls 12 galvanized 18 30 remove existing cluvert, install new 18" x 30' culvert, install new 18" precast concrete headwalls 13 galvanized 18 30 remove existing cluvert, install new 18" x 30' culvert, install new 18" precast concrete headwalls 14 galvanized 18 30 remove existing cluvert, install new 18" x 30' culvert, install new 18" precast concrete headwalls 15 galvanized 18 30 remove existing cluvert, install new 18" x 30' culvert, install new 18" precast concrete headwalls 16 galvanized 18 30 remove existing cluvert, install new 18" x 30' culvert, install new 18" precast concrete headwalls 17 galvanized 18 30 remove existing cluvert, install new 18" x 30' culvert, install new 18" precast concrete headwalls

High Germany Road 11,185

168' of 18" culvert pipe 24' of 24" culvert pipe

14 - 18" headwalls 2 - 24" headwall

Bowsers Orchard Road 8,887

60' of 18" culvert pipe 4 - 18" headwalls

Upper Corners Road

8,100

680' of 18" culvert pipe 40' of 36" culvert pipe

32 - 18" headwalls 2 - 36" headwalls

Appendix C - Information Table

Appendix D - Maps