1、. 30.1 GENERAL 30.1.1 Description Section 30 THERMOPLASTIC PIPE This work shall consist of furnishing and installing thermoplastic pipe in conformance with these Specifica- tions, any special provisions, and the details shown on the plans. As used in this specification, thermoplastic pipe is defined
2、 in Division I, Section 17, “Soil-Thermoplastic Pipe Interaction Systems.” 30.1.2 Workmanship and Inspection All thermoplastic pipe materials shall conform to the workmanship and inspection requirements of AASHTO M 278, M 294, or M 304; or ASTM F 679, F 714, F 794, or F 894 as applicable. 30.2 WORKI
3、NG DRAWINGS Whenever specified or requested by the Engineer, the Contractor shall provide manufacturers installation in- structions or working drawings with supporting data in sufficient detail to permit a structural review. Sufficient copies shall be furnished to meet the needs of the Engi- neer an
4、d other entities with review authority. The work- ing drawings shall be submitted sufficiently in advance of proposed installation and use to allow for their review, revision, if needed, and approval without delay of the work. The Contractor shall not start construction of any thermoplastic pipe ins
5、tallations for which working draw- ings are required until the drawings have been approved by the Engineer. Such approval will not relieve the Con- tractor of responsibility for results obtained by use of these drawings or any of the other responsibilities under the contract. 30.3 MATERIALS 30.3.1 T
6、hermoplastic Pipe Polyethylene pipe shall conform to the requirements of AASHTO M 294, or ASTM F 714, or ASTM F 894. Poly(Viny1 Chloride) (PVC) pipe shall conform to the requirements of AASHTO M 278 or M 304; or ASTM F 679 or F 794. 30.3.2 Bedding Material and Structurai Backfill Bedding and structu
7、ral backfill shall meet the re- quirements ofAASHTO M 145,A-1, A-2-4, A-2-5, or A- 3. Bedding material shall have a maximum particle size of 1.25 inch. Backfill for thermoplastic pipe shall be free of organic material, stones larger than 1 !4 inch in great- est dimension, or frozen lumps. Moisture c
8、ontent shall be in the range of optimum (typically -3% to +2%) per- mitting thorough compaction. Consideration should be given to the potential for migration of fines from adja- cent materials into open-graded backfill and bedding materials. For pipe types that are not smooth on the outside (cor- ru
9、gated or profile walls), backfill gradations should be se- lected that will permit the filling of the corrugation or pro- file valleys. Flowable fills, such as controlled low strength mortar (CLSM) or controlled density fill (CDF), may be used for backfill and bedding provided adequate flotation re-
10、 sistance can be achieved by restraints, weighting, or placementtechnique. With CLSM backfill, trench width can be reduced to a minimum of the outside diameter plus 12 inches. When CLSM is used all joints shall have gaskets. 687 - 688 HIGHWAY BRIDGES 30.5.4 30.4 ASSEMBLY 30.4.1 General Thermoplastic
11、 pipe shall be assembled in accordance with the manufacturers instructions. All pipe shall be un- loaded and handled with reasonable care. Pipe shall not be rolled or dragged over gravel or rock and shall be pre- vented from striking rock or other hard objects during placement in trench or on beddin
12、g. Thermoplastic pipe shall be placed in the bed starting at the downstream end. 30.4.2 Joints Joints for thermoplastic pipe shall meet the perfor- mance requirements for soiltightness unless watertight- ness is specified. (a) Corrugated bands (with or without gaskets) (b) Bell and spigot pipe ends
13、(with or without gaskets) (c) Double bell couplings (with or without gaskets) 30.5 INSTALLATION 30.5.1 General Installation Requirements Trenches must be excavated in such a manner as to in- sure that the sides will be stable under all working condi- tions. Trench walls shall be sloped or supported
14、in con- formance with all standards of safety. Only as much trench as can be safely maintained shall be opened. All GLIIG atmi UG UdLKlllltxI as soon as praciicabie, but not later than the end of each working day. Trench details, including foundation, bedding, haunch- ing, initial backfill, final ba
15、ckfill, pipe zone, and trench width are shown in Figure 30.5.1. - I.“ -L 11 L- L.-l-c*l- 2 - - - - 30.4.2.1 Field Joints 30.5.2 Trench Widths Joints shall be so installed that the connection of pipe sections will form a continuous line free from irregulari- ties in the flow line. Suitable field join
16、ts can be obtained with the following types of connections: Trench width shall be sufficient to ensure working room to properly and safely place and compact haunching and other backfill materials. The space between the pipe Trench Width L t . . 4 12“: , 4“-6“ Central Bedding (see Article 30.5.3) FIG
17、URE 30.5.1 30.5.5 DIVISION II-CONSTRUCTION 689 and trench wall must be wider than the compaction equip- ment used in the pipe zone. Minimum trench width shall not be less than 1.5 times the pipe outside diameter plus 12 inches. Trench width in unsupported, unstable soils will depend on the size of t
18、he pipe, the stiffness of the backfill and in situ soil, and the depth of cover. The trench shall be excavated to the width, depth, and grade as indi- cated on the plans andor given by the Engineer. jetting the structural backfill to achieve compaction shall not be permitted without written permissi
19、on from the Engineer. Backfill materials more than one foot above the pipe to final grade shall be selected, placed, and compacted to sat- isfy the loading, pavement, and other requirements above the pipe. 30.5.5 Minimum Cover 30.5.3 Foundation and Bedding Foundation and bedding shall meet the requi
20、rements of Article 30.3.2 and shall be installed as required by the En- gineer according to conditions in the trench bottom. A sta- ble and uniform bedding shall be provided for the pipe and any protruding features of its joint andor fittings. The middle of the bedding equal to one-third the pipe O.
21、D. should be loosely placed, while the remainder shall be compacted to a minimum 90% of maximum density per AASHTO T 99. A minimum of 4 inches of bedding shall be provided prior to placement of the pipe unless other- wise specified. When rock or unyielding material is present in the trench bottom, a
22、 cushion of bedding of 6 inches minimum thickness shall be provided below the bottom of the pipe. When the trench bottom is unstable, material shall be excavated to a depth as required by the Engineer and re- placed with a suitable foundation. A suitably graded ma- terial shall be used where conditi
23、ons may cause migration of fines and loss of pipe support. 30.5.4 Structural Backfill Structural backfill shall meet the requirements of Arti- cle 30.3.2. Structural backfill shall be placed and com- pacted in layers not exceeding an 8 inch loose lift thick- ness and brought up evenly and simultaneo
24、usly on both sides of the pipe to an elevation not less than one foot above the top of the pipe. Structural backfill must be worked into the haunch area and compacted by hand. A minimum compaction level of 90% standard density per AASHTO T 99 shall be achieved. Special compaction means may be necess
25、ary in the haunch area (See Figure 30.5.1). All compaction equipment used within 3 feet of the pipe shall be approved by the Engineer. Ponding or A minimum depth of cover above the pipe should be maintained before allowing vehicles or heavy construc- tion equipment to traverse the pipe trench. The m
26、inimum depth of cover should be established by the Engineer based on an evaluation of specific project conditions. For embedment materials installed to the minimum density given in Article 30.5.4, cover of at least 24 inches shall be provided before allowing vehicles or construction equip- ment to c
27、ross the trench surface. Hydrohammer type com- pactors shall not be used over the pipe. 30.5.6 Installation Deflection The internal diameter of the barrel shall not be reduced by more than 5% of its base inside diameter when measured not lesS.than 30 days following completion of installation. 30.6 M
28、EASUREMENT Pipe installations shall be measured in linear feet in- stalled in place, completed, and accepted. The number of feet shall be the centerline lengths of the pipe. 30.7 PAYMENT The length as measured above will be paid for at the contract prices per lineal foot bid for thermoplastic pipe o
29、f the sizes specified. Such price and payment shall con- stitute full compensation for furnishing, handling, and in- stalling the pipe and for all materials, labor, equipment, tools, and incidentals necessary to complete this item. Such price and payment shall also include excavation, bedding material, backfill, headwalls, endwalls, and foun- dations for pipe.
