15-14 on the weight of standard size ductile iron sewer pipe fittings. Any fittin g not listed will be 1
measured based on the published weights for ductile iron fittings listed in AWWA C - 2 110/A21.10. This is limited to pressure pipe 4 inches or larger. 3 Payment will be made under: 4 Pay Item Pay Unit __" Sanitary Gravity Sewer Linear Foot __" Force Main Sewer Linear Foot Sanitary Sewer Clean -Out Each Sewer Service Line Linear Foot Ductile Iron Sewer Pipe Fittings Pound SECTION 1525 5 UTILITY MANHOLES 6 1525 -1 DESCRIPTION 7 Provide utility manholes on water and sanitary sewer lines. 8 1525 -2 MATERIALS 9 Refer to Division 10. 10 Item Section Brick 1040 -1 Concrete Block 1040 -2 Curing Materials 1026 Gray Iron Castings 1074 -7(B) Grout, Type 2 1003 Mortar 1040 -9 Portland Cement Concrete 1000 Precast Concrete Units 1077 Reinforcing Steel 1070 Select Material s 1016 Steps 1074 -8 Structural Steel 1072 Use precast concrete manholes with monolithic bottoms which conform to ASTM C478, 11 AASHTO M 199 and are as shown in the plan s or in Roadway Standard Drawings . Use 12 ASTM C443 gaskets or ASTM C990 flexible sealants for joints between precast manhole 13 sections. Use resilient connectors for piping conforming to ASTM C923. Use ASTM A48, 14 Class 35 cast iron or Grade 60 steel reinforcement steps with polypropylene plastic coating. 15 Use manhole frames and covers made of cast iron conforming to ASTM A48 Class 35, which 16 are traffic bearing, have machined contact surfaces and are sized as shown. Use covers with 17 two 1 inch diameter air vents for vented manholes and use solid, non- vented covers with 18 gaskets for watertight installation. Use covers with “Sanitary Sewer” or “Water” cast in large 19 letters as appropriate for the type of utility. 20 Use Type 2 grout with prope rties that meet Table 1003 -2 except provide grout with a plastic 21 consistency in accordance with ASTM C1107. 22 1525 -3 CONSTRUCTION METHODS 23 Apply Section 1505 for excavation, trenc hing, pipe laying and backfill. 24 Make connections of pipe to manholes in cored or precast holes using a resilient connector. 25 Use horseshoe type holes only when approved by the Engineer . For horseshoe type holes 26 wrap the pipe with a butyl rubber gasket and fill the space between the pipe and manhole with 27 a non- shrinking grout. 28
15-15 Provide an outside drop assembly on manholes for sewer pipes entering with 2.5 feet or more 1
vertical drop. Inside drop assemblies may be used for connections to existing manholes when 2 the drop exceeds 5 f eet and the manhole diameter is greater than 4 f eet. 3 In sewer manholes over 3 f eet in depth, provide steps spaced 16 inches on center. Install steps 4 in line with the effluent openi ng unless otherwise specified. 5 Construct invert channels to confine and direct the flow through sanitary sewer manholes. 6 Use smooth finished invert channels that provide easy transition from inlet to outlet. Finish 7 the benches or shelves to a non- slip texture and slope toward the invert channel. Precast 8 invert channels are recommended but not required. 9 On deep manholes, a transition type manhole may be used provided there is at least 6 feet 10 from the manhole bench to the transition cone. 11 Construct manholes with the top of the cover as shown in Table 1525- 1. 12 TABLE 1525 -1 MANHOLE CONSTRUCTION Location Top height above finished grade Roadway pavement , Driveways, Sidewalks , Parking lots Flush ± 1/ 4" Vehicle Recovery Area Flush ± 3 " Manicured Areas, such as lawns Flush to + 2" with concrete pad Flood Zones less than 3 ft above finished grade 1 ft above 100 year flood elevation Flood Zones greater than 3 ft above finished grade 2 ft above finished grade with watertight frame and cover and vent pipe to 1 ft above 100 year flood Other areas 2 ft above finished grade For manholes installed before finished grading or paving, construct the top flush with the 13 current grade to provide access during all phases of construction and adjust as grading and 14 paving work progresses in accordance with Section 858. 15
A.Cast -In-Place Concrete, Brick and Block Masonry 16 Construct concrete manholes in accordance with Section 825 with an ordinary surface 17 finish. Construct brick masonry in accordance with Section 830. Furnish and place 18 reinforcing steel in accordance with Section 425. Construct block masonr y in accordance 19 with Section 834 except that reinforcing will not be required. 20 Where necessary to fit field conditions, vary the dimensions of the manhole and footings 21 as directed. 22
B.Installation of Precast Units 23 Assemble precast manhole units in accordance with the manufacturer’s instructions and 24 grout together to form a sound structural unit. Fill all lifting holes with grout. Where it is 25 necessary to use cast -in-place, brick masonry or block masonry construction as part of the 26 structure, apply Subarticle 1525 -3(A) to such construction. 27
C.Fittings and Connections 28 Where fittings enter the manhole, place them as the work is built up, thoroughly bonded 29 and accurately spaced and aligned. 30 Make pipe connections so that the pipe does not project beyond the inside wall of the 31 manhole and grout smooth and uniform surfaces on the inside of the manhole. 32 Set metal frames for covers in full mortar beds and mechanicall y secure by an approved 33 method. 34
Source: North Carolina Standard Specifications for Roads and Structures, 2024 Edition. Pages 740–741 of 857.