Article 1 — Description
Furnish and install thermoplastic pipe for constructing thermoplastic pipe culverts and drains. In this Specification, all references to thermoplastic pipe include all pipe, joints, and fitting materials. Provide pipes of the sizes, types, design, and dimensions shown on the plans, including the connections and joints to new or existing pipes, storm sewer, manholes, inlets, headwalls, and other appurtenances as required to complete the work. Use of this S pecification requires concrete end treatment attached, including concrete headwalls, wingwalls, and floor on exposed ends of pipe.
Article 2 — Materials
Manufacturing plants must be approved in accordance with DMS -4710 , “Thermoplastic Pipe, Joints, and Fittings,” before furnishing thermoplastic pipe for Department projects. The Department’s MPL includes approved manufacturing plants and products. Unless otherwise shown on the plans, furnish materials in accordance with the following: DMS -4710 Item 400, “Excavation and Backfill for Structures ” Item 401, “Flowable Backfill. ” Provide excavatable flowable backfill when Item 401 is speci fied.
2.1 Inspection . The quality of materials, the process of manufacture, and the finished pipe will be subject to
inspection and approval at the manufacturing plant. In addition, the finished pipe will be subject to further random inspection at the project site before and during installation.
2.2 Joints . Install the joints so that the connection of the pipe sections forms a continuous line free of
irregularities in the flow line. If no joint type is specified, provide a soil- tight joint meeting the requirements of DMS -4710 .
Article 3 — Construction
Construct the pipe at locations shown on the plans or as directed. Only trench installation of thermo plastic pipe will be permitted.
3.1 Contractor Submittals. Submit to the Engineer the following documentation upon delivery of material .
Certificate of Compliance. Submit a certificate of compliance of pipe product to the Department with the following information, manufacturing plant, date of manufacture, pipe dimensions, pipe stiffness, pipe flattening, brittleness, ASTM resin cell classification, and workmanship. Installation Specifications. Provide manufacturer’s installation specifications to Engineer before beginning work. Include maximum fill depth and backfill requirements in manufacturer’s installation specifications.
3.2 Marking . Install only pipe that is clear ly marked at maximum 10 ft. intervals and clearly mark all couplings
with: manufacturer’s name or trademark , nominal size, 734 specification designation (i.e., AASHTO M 294 or AASHTO M 330), manufacturing plant’s designation code, and date manufactured.
3.3 Excavation . Excavate in accordance with Item 400.
Provide enough trench width for the pipe installation to ensure adequate working room to properly and safely place and compact materials placed under haunches of the pipe and other embedment m aterials. Provide space between the pipe and trench wall that is greater than that of the compaction equipment used. If ground water is encountered, de- water the trench before placing and backfilling the pipe. However, restrain pipe to maintain elevation and alignment if water exists in trench when allowed by the Engineer for wet placement. Maintain trench shoring system above pipe haunch zone to not disturb during shoring removal. Correct excavation and backfill if disturbed to reestablish the integrity of the bedding and backfill specified herein. When using flowable backfill, the minimum allowable trench width is the pipe outside diameter plus 12 in. When using a granular or a cement stabilized backfill, the minimum allowable trench width is specified i n Table 1. Table 1 Min Trench Width (Granular and Cement Stabilized Backfill) Nominal Pipe Diameter (in.) Min Trench Width (in.) 18 39 24 48 36 66 42 75 48 84
3.4 Installing Pipe in Embankment. If any portion of the pipe projects above the existing ground level, construct
an embankment as shown on the plans or as directed, for a minimum distance outside each side of the pipe location of five times the diameter and to a minimum elevation of 2 ft. above the top of the pipe. Excavate the trench to a width as specified in Section 3.3., “Excavation.”
3.5 Bedding. Bed the pipe in a foundation of cohesionless material, such as sand, crushed stone, or pea gravel,
with a maximum allowable size of 3/8 in. Provide bedding with 4 in. minimum thickness unless subgrade contains large rocks in which increase to minimum of 6 in. Compact the bedding except the width of one third the width of pipe diameter directly under the centerline of the pipe – leave this region loose (uncompacted).
3.6 Handling and Storing Pipe. Store pipe above ground on adequate blocking. Always keep pipe clean and
fully drained during storage. Provide proper equipment for hoisting and lowering the pipe into the trench without damaging the pipe or disturbing the bedding or the walls of the trench. Any protective covering of gaskets should remain until the pipe is ready for installation.
3.7 Laying Pipe. Unless otherwise authorized, start laying pipe on the bedding at the outlet end with the
separate sec tions firmly joined together. Hoist and lower sections of pipe into the trench without damaging the pipe or disturbing the bedding or the sides of the trench. Remove and re- lay any pipe that is not in alignment or that shows excessive settlement after layi ng, at no expense to the Department. Lay multiple installation of thermoplastic pipe with the centerlines of the individual barrels parallel. Unless otherwise shown on the plans, maintain the clear distances between outer surfaces of adjacent pipes shown in Table 2 . 735 Table 2 Min Clear Distance Between Pipes Nominal Pipe Diameter (in.) Min Clear Distance Between Pipes (in.) 18 14 24 17 30 20 36 23 42 26 48 29
3.8 Reusing Existing Appurtenances. When existing appurtenances are specified on the plans for reuse,
sever the portion to be reused from the existing culvert and move it to the new position previously prepared, by approved methods. Provide connections conforming to the requirements for joi ning sections of pipes as indicated in this specification or as shown on the plans. Restore any headwalls and any aprons or pipes attached to the headwall that are damaged during moving operations, to their original condition, at no expense to the Department. The Contractor has the option to remove and dispose of the existing headwalls and aprons and construct new headwalls at no expense to the Department, in conformance with the pertinent specifications and design indicated on the plans or as furnished.
3.9 Pipe Joint ing. Follow pipe manufacturer’s installation specifications when joining pipes together. Remove
gasket protective film just before joining pipes. Provide suitable protection to the push end of the pipe if force is applied to end of pipe to obtain r equired overlap. Do not damage pipe during pipe joining operations. At a minimum, achieve the minimum specified overlap of the two pipes within the connection. Do not over join pipes to disrupt flow line inside of pipe. Suitable joints are as follows. Integral Bell and Spigot. Ensure the bell overlaps a minimum of two corrugations of the spigot end when fully engaged. Provide the spigot end with an O -ring gasket in accordance with ASTM F477. Exterior Bell and Spigot. Fully weld the bell to the exterior of t he pipe and overlap the spigot end so that the flow lines and ends match when fully engaged. Provide the spigot end with an O -ring gasket in accordance with ASTM F477. Split Couplers. For soil -tight joint connections only. Join pipe with coupling bands cov ering at least two full corrugations on the ends of each pipe being joined.
3.10 Sewer Connections and Stub Ends. Make connections of pipe sewer to existing sewers or sewer
appurtenances as shown on the plans or as directed. Mortar or concrete the bottom of the existing structures, if necessary, to eliminate any drainage pockets created by the new connection. Where the sewer is connected into existing structures which are to remain in service, restore any damage to the existing structure resulting from making t he connection to the satisfaction of the Engineer. Seal stub ends, for connections to future work not shown on the plans, by installing watertight plugs into the free end of the pipe. Include the cost for the above in cost of the pipe.
3.11 Backfilling. Backfill from the pipe bedding up to 12 in. above the top of the pipe to provide necessary
structural support to the pipe and control pipe deflection. Take care when placing and compacting the backfill material to not damage pipe. Adjust backfilling operat ions if pipe is being moved out of alignment, is causing pipe distortion, or disrupting joint tightness. Remove backfill around problem areas and restore pipe section before continuing to backfill. Provide uniform backfill material and uniform compacted density throughout the length of the pipe, to avoid unequal pressure. Use care to ensure proper backfill under the pipe, in the haunch zone. Provide type of backfill as shown on the plans. When granular material is specified, provide backfill consisting of hard, durable, clean granular material that is free of organic matter, clay lumps, and other deleterious matter. Provide backfill meeting the gradation requirements shown in Table 3. 736 Table 3 Gradation Requirements for Granular Backfill Material Sieve Size Percent Retained (Cumulative) 1 in. 0–5 7/8 in. 0–35 1/2 in. 0–75 3/8 in. 0–95 No. 4 35–100 No. 10 50–100 No. 200 90–100 Place the backfill in accordance with Item 400 or Item 401 and as supplemented below . Granular Backfill. Place in uniform layers a minimum 6 in. deep (loose measurement), wet if required, and thoroughly compact it between adjacent structures and between the structure and the sides of the trench. Hand place, if necessary, under the pipe in haunch zone to ensure complete filling and support. Limit compaction to hand- operated tamping equipment to compact backfill within the region 12 in. either side of the pipe and between pipes. Place filter fabric between the native soil and the backfill unless otherwise shown on the plans. Use filter fabric conforming to the requirements of DMS -6200 , “Filter Fabric,” Type 1. Cement Stabilized Backfill. Place and compact to completely fill all voids. Hand place, if necessary, under the pipe in haunch zone to ensure complete filling and support. Flowable Backfill. Place in a manner that will not result in uplift of the pipe or restrain pipe enough to maintain constant grade flowline at required elevation. Place across the entire width of the trench and maintain a minimum depth of 12 in. above the pipe. Wait a minimum of 24 hr. before backfilling the remaining portion of the trench with other backfill material in accordance with Item 400, unless strength information for the flowable fill is available and strength exceeds 100 psi compressive strength. Inspect inside periphery of pipe for local or unequal deformation caused by improper construction methods during backfilling. Stop work and address backfilling technique if measured deflection of pipe exceeds 5% or there are other issues found effecting quality of pipe installation. To validate pipe installation methods, perform an initial quality control inspection after first installation of each size of pipe is completed on the project. Notify the Engineer when this inspection takes place.
3.12 Protecting the Pipe. Unless otherwise shown on the plans or permitted in writing, do not use heavy earth-
moving equipment over the structure until a minimum of 4 ft. of permanent or temporary compacted fill is placed over the top of the structure.
Article 4 — Inspection Or Acceptance
4.1 Inspection. Visually inspect the pipes for damage, deflection (out of roundness), joint tightness, evidence of
soil intrusion, and vertical alignment (ponding). If the pipe run is 30 ft. or less in length, not under a public roadway, and the initial visual inspection did not indicate any deflection or other deficiencies, additional testing described below will be waived, unless otherwise noted. Provide high intensity lights, laser distant measuring devices, and other equipment to facilitate visual inspection. Perform final inspection a minimum of 30 days after the backfill has been completed or earlier as needed to allow roadway surfacing when approved. Have two test mandrels available for each size of pipe. Size mandrels based on the manufacturer’s average inside diameter and field verified based on a proving ring. Provide metal mandrels with at least nine fixed fins evenly distributed around the circumference. Pull mandrel sized at 95% the diameter of the pipe through the entire length. If the 95% mandrel cannot be pulled entirely through, pull a mandrel 92.5% the pipe diameter through the pipe. Additionally, if the 95% mandrel cannot be pulled entirely through the pipe or there is a substantial disruption in ease of mandrel movement through the pipe, visually inspect installed pipe utilizing a remote operated camera mounted on vehicle or sled able to 737 move through the pipe. Check for joint separation, cracks, tears, buckling, deflection, and out of roundness, evidence of soil intrusion and vertical alignment (ponding water). Notify the E ngineer when inspections are to occur. The D epartment will provide inspection form to be used. Document process and findings and return form to the Engineer.
4.2 Remediation. Develop a plan to address all deficiencies of joint separation, damage, evidence of soi l
intrusion, vertical alignment, and when pipe deflection exceeds 5% of the nominal diameter. Joints . Remediate pipe showing evidence of crushing at the joints. Note differential movement, improper joint sealing, movement or settlement of pipe sections, and leakage in the inspection report. Remediate joint separation of greater than 1 in. Repair or replace pipe sections where soil migration through the joint is occurring. Cracks or Tears. Remediate cracks or splits in the interior wall of the pipe. Use remediation methods in conformance with recommendations of the pipe manufacturer and accepted and authorized by the Engineer. Buckling, bulging, and racking. Note in the inspection report flat spots or dents at the crown, sides , or flowline of the pipe due to racking. Note areas of wall buckling and bulging in the inspection report. The Engineer will determine if corrective action is necessary. Deflection . Where pipe deflection exceeds 5% o f the nominal diameter, submit to the Engineer for review and approval an evaluation utilizing a Professional Engineer taking into consideration the severity of the deflection, structural integrity, environmental conditions, and the design service life of the pipe. Remediate or replace pipe where the evaluation finds the deflection could be problematic or where pipe deflection exceeds 7.5% of the nominal diameter.
Article 5 — End Treatment
Install concrete end sections per requirements of the plans. End section must include concrete headwall, wings, and floor. Reference the following for this work. Item 466, “Headwalls and Wingwalls” Item 467, “Safety End Treatment”
Article 6 — Measurement
This Item will be measured by the foot. Measurement will be made between the ends of the pipe barrel along the flow line, not including safety end treatments. Measurement of spurs, branches, or connections to existing pipe will be made from the intersection of the flow line with the outside surface of the pipe into which it connects. Where inlets, headwalls, catch basins, manholes, junction chambers, or other structures are included in lines of pipe, the length of pipe tying into the structure wall will be included for measurement, but no other portion of the structure length or width will be incl uded. For multiple pipes, the measured length will be the sum of the lengths of the barrels. This is a plans quantity measurement Item. The quantity to be paid for is the quantity shown in the proposal unless modified by Article 9.2., “Plans Quantity Measurement.” Additional measurements or calculations will be made if adjustments of quantities are required.
Article 7 — Payment
The work performed and materials furnished, in accordance with this Item and measured as provided under “Measurement ,” will be paid for at the unit price bid for “Thermoplastic Pipe” of the size and type specified. This price is full compensation for furnishing, hauling, placing, and joining pipes; connecting to new or 738 existing structures; moving and reusing headwalls where required; removing and disposing of portions of existing structures as required; cutting of pipe ends on skew; inspection and testing; and labor, tools, equipment, and incidentals. Excavation, shaping, bedding, and backfill will be paid for in accordance with Item 400. Flowable backfill will be paid in accordance with Item 401. Concrete end treatments will be paid in conformance with other items o n the plans .