21-333913 Storm Sewer Structures.pdf

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SECTION 333913

STORM SEWER STRUCTURES

PART 1 GENERAL

2.1 WORK INCLUDED

A. This work consists of furnishing and installing storm sewer manholes of the type specified and depicted on the plans, at the depth indicated. This work includes but is not limited to: the installation manholes of the type specified at the locations indicated on the plans.

3.2 RELATED WORK SPECIFIED ELSEWHERE

B. Storm Sewer Pipe - Section 02723

4.3 REFERENCE STANDARDS

C. Pennsylvania Department of Transportation (PennDOT) Publication No. 72, latest edition.

D. Pennsylvania Department of Transportation (PennDOT) Publication No. 408, latest edition.

E. American Society for Testing of Materials (ASTM)

A 48 Standard Specifications for Gray Iron Castings

C 478 Standard Specification for Precast Reinforced Concrete

Manhole Sections

C 913 Standard Specifications for Precast Concrete Water and

Wastewater Structures

C 923 Standard Specification for Resilient Connectors Between

Concrete Manhole Structures and Pipe

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5.4 SUBMITTALS

F. Before any work is started, submit Certificates of conformance for all precast concrete structures to the Engineer, in triplicate, proving conformance with specifications. All precast concrete components shall be covered by a guarantee certificate furnished by the Contractor and signed by an officer of the precast manufacturer.

B. Submit manufacturer's data for the following manufactured inlet components:

1. Frame and cover

2. Other special or unique components

PART 6 PRODUCTS

7.5 MATERIALS

G. Concrete:

3. Unless otherwise indicated, concrete shall be in accordance with Section

704 of PennDOT Publication 408, current edition for Class AA cement concrete with a minimum 28 day compressive strength of 3,750 p.s.i. and an entrained air content of 6%.

H. Brick and Mortar:

4. Brick: Conform to ASTM C 32 Grade SM.

5. Mortar:

a. Aggregate: ASTM C 144.

b. Portland Cement: ASTM C 150, Type I, of natural color - or white to produce required color.

c. Hydrated Lime: ASTM C 207, Type S.

d. Water: Clean and potable.

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6. Mortar Applications: One part portland cement and two parts sand with hydrated lime added not to exceed 20% of the "cement by weight".

I. Mortar:

7. Use mortar meeting the requirements of ASTM C 270 entitled Mortar for

Unit Masonry. Use Type M mortar consisting of: (1) part portland cement;

(1/2) part hydrated lime; and fine aggregated, measured in a damp, loose condition in an amount not less than (2-¼) or more than (3) times the sum of the volumes of the cement and lime used.

8. If required use the type of chemically resistant mortar indicated.

J. Precast Storm Sewer Manholes:

9. General: Provide precast reinforced concrete sanitary manholes as indicated, and complying with ASTM C478.

10. The sections shall conform to the requirements of "Specifications for

Precast Reinforced Concrete Manhole Sections" (ASTM C 478), except that the joints shall be sealed with a Preformed Plastic Gasket that meets or exceeds all requirements of Fed. Spec. SS-S-00210, "Sealing Compound Preformed Plastic for Pipe Joints", Type 1, Rope Form.

11. The Sealing Compound shall be produced from blends of refined hydrocarbon resins and plasticizing compounds reinforced with inert mineral filler, and shall contain no solvents, irritating fumes or obnoxious odors. The compound shall not depend on oxidizing, evaporating, or chemical action for its adhesive or cohesive strength. It shall be supplied in extruded rope-form or suitable cross-section and of such sizes as to seal the joint space when the sections are set in place. The sealing compound shall be protected by a suitable removable two-piece wrapper. The two-piece wrapper shall be so designed that one-half may be removed longitudinally without disturbing the other half to facilitate application of the sealing compound.

12. The top of base walls, the ends of reinforced concrete risers and the bottom ends of precast tops shall be so formed that when risers and tops are assembled with the base, they will make a continuous manhole. Joints shall be of such design as will permit effective joining and placement without irregularities in the interior wall surface of the manhole.

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13. Manhole barrels shall consist of riser and top sections with a minimum wall thickness of 5 inches. The top section shall be an eccentric conical section with thickened upper walls with the smallest inside diameter equal to 24 inches, to receive the manhole frame and cover. No more than 2 lift holes shall be cast in each barrel or top section.

14. Manhole riser and top sections shall be designed, manufactured, tested, finished and marked in accordance with this specification and ASTM C 478.

15. Top: Precast concrete, of concentric cone, eccentric cone, or flat slab top type, as indicated.

16. Base: Precast concrete, with base riser section and separate base slab, or base riser section with integral floor, as indicated.

17. Steps: Aluminum for manhole steps shall be manufactured and tested in accordance with ASTM B 221 Standard Specification for Aluminum- Alloy Extruded Bars, Rods, Wire, Shapes and Tubes, Alloy 6061 T6.

Embedded ends of aluminum steps shall have 2 coats of bitumastic. Steps shall be located a minimum of 6 inches from the ends of riser and top sections.

18. Pipe Connectors: Resilient complying with ASTM C 923.

E. Connections to Manholes

19. Unless otherwise indicated seal joints between pipes and structures with non-shrink, non-metallic mortar. The mortar shall not contain gas-forming agents; the volume change shall be 0 or shall increase slightly; the time of set shall be a minimum of 45 minutes and the 28 day compressive strength shall be 6000 psi.

20. If indicated, use resilient connectors to insert pipe into precast reinforced concrete manholes. Resilient connectors shall meet the requirements of ASTM C 923 Standard Specification for Resilient Connectors Between Reinforced Concrete Manhole Structures and Pipe and must be approved by the Engineer prior to use.

F. Reinforcement:

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21. Reinforcing bars shall conform to ASTM A 615, Standard Specifications for Deformed Billet-Steel Concrete Reinforcement.

22. Welded wire fabric shall conform to ASTM A 185, Standard Specification for Welded Steel Wire Fabric for Concrete Reinforcement.

G. Manhole Steps

23. If the depth of Inlet or Manhole exceeds four (4) feet, steps will be required. The materials for steps shall be as follows:

e. Aluminum for manhole steps shall be manufactured and tested in accordance with ASTM B 221 Standard Specification for Aluminum-Alloy Extruded Bars, Rods, Wire, Shapes and Tubes, Alloy 6061 T6. Embedded ends of aluminum steps shall have 2 coats of bitumastic.

H. Manhole Frame and Cover:

24. Manhole frames and cover shall be of the type and size specified and shall include bolts, gaskets and hardware, if indicated.

25. Manhole frames and covers shall be made of Class 35B gray iron which is tested in accordance with ASTM A 48 Standard Specification for Gray Iron Castings. The name of the foundry and the heat and lot number shall be cast into the frame and into the exterior side of the cover.

26. Manhole frames and covers shall be thoroughly cleaned. All projections and roughness shall be ground smooth. The bearing surfaces of the frame and cover shall not rock or jam.

27. Castings shall be of uniform quality, free from blowholes, porosity, hard spots, shrinkage distortion of other defects. They shall be smooth and well-cleaned by shotblasting or by some other approved method. They shall be coated with asphalt paint which shall result in a smooth casting, tough and tenacious when cold, not tacky and not brittle. Materials shall conform to ASTM A 48 C1.30. The riser and cone sections shall be adequately reinforced in accordance with ASTM C 478 Specifications.

I. Grout

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1. Nonshrinking Grout

a. Required for patching manholes, pipes and plugging.

b. Grout shall be nonmetallic, as manufactured by one of the following:

1) Crystex, L and M Construction Chemicals, Inc.

2) Five Star Grout, U.S. Grout Corporation.

3) Masterflow 713 grout, Master Builder's, Inc.

4) Sauereisen F-100, Sauereisen Cement Company.

5) Supreme Grout, Gifford-Hill and Company.

6) Ferrolith C, Sonneborn-Contech.

7) EUCO NS, Euclid Chemical.

c. Prepare and place to manufacturer's printed instructions.

PART 8 EXECUTION

9.6 EXCAVATION, SUBGRADE PREPARATION AND BACKFILL

K. Excavation:

28. Excavation includes the removal of material of whatever nature encountered including existing structures within the limits of excavation, from the top of existing grade, or from the pavement subgrade line when existing paving is to be removed, to the inlet subgrade.

29. When constructing manholes in conjunction with existing pipes excavate in a safe manner down to the subgrade, and in a manner that will not disturb the existing pipes.

30. The existing frame and grate, or other salvageable appurtenances become the property of the Contractor unless the inspector gives written notice to the contractor that these items will be reclaimed by the Muncipality. The

333913-7 written notice will be issued prior to the contractor beginning the reconstruction work and will specify the items to be reclaimed and the location to which the Contractor shall deliver the reclaimed items.

Carefully remove items to be reclaimed by the Municipality and clean any excess concrete or mortar shall be cleaned from the surface prior to delivery to the Municipality.

31. Use sheathing and shoring in the excavation, as required and necessary. It shall be left in place and shall be of sufficient strength to withstand all external pressures.

L. Subgrade Preparation:

32. Surface grade fill material or subgrade beneath the structure to provide a uniform, firm and continuous support. Density fill material beneath the structure.

33. No structure shall be placed upon a foundation into which frost has penetrated, nor at any time when the Engineer deems that there is a danger of formation of ice or penetration of frost at the bottom of Excavation.

Where the foundation is unsuitable, as determined by the Engineer, over-excavate the pit to a suitable depth and place a stone or gravel foundation and tamped to form an acceptable bed for the structure.

34. Upon completion of subgrading operations, place, level and tamp the

AASHTO #57 stone bed, eighteen (18) inches thick.

M. Backfill:

35. Backfill excavated spaces around the structure, with acceptable material upon approval by the Engineer.

36. Satisfactorily dispose of unsuitable and surplus material.

37. Additional requirements for backfill and compaction are as specified herein for the appropriate conditions.

38. Allow cast-in-place or brick inlets to cure sufficiently prior to backfill.

10.2 MANHOLE CONSTRUCTION

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N. The minimum diameter of manholes shall be 48 inches. A minimum access diameter of 30 inches shall be provided.

O. The flow channel through manholes should be made to conform in shape and slope to that of the sewers. The flow channel shall be constructed to 2/3 the depth of the largest pipe in the manhole.

P. Pipes shall be set in manholes with the pipe end flush with the inside face of the manhole.

Q. If the depth of the manhole exceeds four (4) feet steps will be required and shall be placed in an appropriate wall and spaced 12 inches O.C. vertically from top to bottom of manhole.

R. Where the manhole depth from grade to invert is less than 6'-0" deep, a flat size

(6) inches thick reinforced concrete slab with eccentric opening shall be used upon approval of the engineer.

S. Set frames and grade adjustment rings (if required) in full mortar beds.

T. Precast reinforced concrete risers and cone section shall be provided with handling holes positioned so that the section remains balanced during setting.

After setting the handling holes shall be sealed watertight, using non-shrink, non-metallic type mortar. The entire exterior surface shall be provided with a shop applied bituminous coating equal to Pennsbury Pennoxy Tar 32-B-4. Riser sections shall be furnished in lengths of 1, 2, 3 or 4 feet to suit any depth to within one foot, however, the number of joints shall be minimized.

11.3 TESTING AND ACCEPTANCE

U. The Contractor shall cooperate and furnish all equipment, labor, and assistance necessary to perform testing required by the Engineers unless otherwise specified.

V. If required by the Engineer a manhole test shall be performed to determine the watertightness of the manhole.

W. All defects found shall be repaired or replaced by the Contractor, at his expense, to the full satisfaction of the Engineer prior to acceptance.