MANHOLES

PART 1 - GENERAL

1.01 SECTION INCLUDES

A. Manholes for sanitary and storm sewers.

B. Adjustment of existing manholes.

C. Connection to existing manholes.

D. Abandonment of manholes.

E. Existing Manhole Rehabilitation

1.02 DESCRIPTION OF WORK

A. Construct sanitary and storm sewer manholes, modify existing manholes, and abandon manholes where shown in on the Pplans.

B. Rehabilitate existing manholes to waterproof and prevent inflow and infiltration, prevent corrosion, or reestablish the structural integrity of the manhole. Includes construction of structural liners, protective liners, and chimney seals.

C. Reference is made to the Iowa Department of Transportation Standard Specifications for Highway and Bridge Construction, Series 2001, and all current General Supplemental Specifications and Materials Instructional Memorandum by the term "Iowa DOT Specifications" and/or " Iowa DOT I.M."

1.03 SUBMITTALS

A. Submit under provisions of Division 1.

B. Shop drawings showing compliance with this Specification.

C. Shop drawing schedule of new manholes showing total depth, relative elevations of all connecting sanitary or storm sewer lines, all drops, and orientation of connecting lines.

D. Catalog cuts of iron castings, chimney seals, and sewer line connection gaskets.

E. Upon requests, the Contractor will provide Material Certifications to the Jurisdictional Engineer.

1.04 SUBSTITUTIONS

A. Use only materials conforming to these specifications unless permitted otherwise allowed by the Jurisdictional Engineer.

B. Obtain written approval of Jurisdictional Engineer for all substitutions prior to use.

C. Precast sections meeting the requirements of ASTM C 478.

1.05 DELIVERY, STORAGE, AND HANDLING

A. Deliver only materials that fully conform to these specifications or for which submittals have been provided to the Jurisdictional Engineer and approved for use.

B. Store and handle materials to avoid damage. Replace any damaged materials. Remove damaged materials from the site.

1.06 SCHEDULING AND CONFLICTS

A. Construction Sequence:

1. Attend a preconstruction meeting if required by the Jurisdictional Engineer.

2. Submit plan for construction sequence and schedule prior to commencing construction.

B. Conflict Avoidance:

1. Expose possible conflicts in advance of construction, such as utility lines and drainage structures. Verify elevations and locations of each and verify clearance for proposed construction.

2. Complete elements of the work which that can affect line and grade in advance of other open cut construction unless noted on the plans.

3. Notify the Jurisdictional Engineer of conflicts discovered or changes needed to accommodate unknown or changed conditions.

1.07 SPECIAL REQUIREMENTS

A. Stop work and notify Jurisdictional Engineer immediately if contaminated soils, historical artifacts, or other environmental or historic items are encountered.

B. Conform to local, state, and Ffederal requirements.

C. Sanitary Manholes and Castings:

1. Manhole Types:

Type Description Main Pipe Size Typical Depth Figure No.
A 48" Min. Dia. Barrel with Eccentric Cone and Integral Precast Base See Table 1, Fig. 6020.1 for Max. Dia. Pipe No Limit 6020.1
E Poured-in-Place Box 18" or Greater Dia. Pipe 6' - 12' 6020.2
F Combination Poured in Place Manhole with 48" Dia. Riser and Eccentric Cone 18" or Greater Dia. Pipe 12' - 22' 6020.3
I 48" Dia. Barrel with Eccentric Cone and Poured in Place Base for Manhole Placement on Existing Sewer 18" Max. Dia. Pipe without Jurisdictional Engineer Approval No Limit 6020.4
J 48" Dia. Barrel with Eccentric Cone and T-Section 42" Dia. or Greater Eccentric Reducer Required 8.5' Min. 6020.5

2. Ring and Cover Types:

Type Ring & Cover No. of Pieces Bolted Frame Bolt Cover Gasketed Figure No.
A Standard* 2 Yes No Yes 6020.7
B Adjustable** 3 No No Yes 6020.8
C Standard* 2 Yes Yes Yes 6020.9
D Adjustable** 3 No Yes Yes 6020.10

* Use when placed in earth fill, asphalt pavement, or ACC manhole boxout.

** Use when placed in PCC pavement or PCC manhole boxout.

D. Storm Sewer Manholes:

1. Manhole Types:

Type Description Main Pipe Size Typical Depth Figure
No.
M-A 48" Min. Dia. Short Cone or Flat Top with Poured or Precast Base See Table 1, Fig. 6020.12 for Max. Dia. Pipe 7' Min. 6020.12
M-B Precast or Poured-in-Place Box with Precast or Poured-in-Place Base 24" or Greater 8' Max. 6020.13
M-C Poured-in-Place Box with Poured-in-Place Base 12" Dia. or Greater 6' - 12' 6020.14
M-D Combination 48" Dia. Short Cone with Poured-in-Place Barrel and Poured-in-Place Base 12" Dia. or Greater 12' - 22' 6020.15
M-E 48" Dia. Short Cone with T-Section 42" Dia. or Greater eccentric reducer required for 42" 8.5' Min. 6020.16

2. Ring and Cover Types:

Type Ring & Cover No. of Pieces Bolted Frame Bolt Cover Gasketed Figure
No.
E* Standard 2 Yes No No 6020.17
F** Adjustable 3 No No No 6020.18
G* Machined Bearing Surfaces 2 No No No 6020.19

* Use when placed in earth fill, asphalt pavement, or ACC manhole boxout.

** Use when placed in PCC pavement or PCC manhole boxout.

1.08 MEASUREMENT FOR PAYMENT

All measurements for payments will be made by the Jurisdictional Engineer or authorized representative.

A. Manhole: For each type and size of manhole required and furnished, measure manhole vertical dimension in feet from the flow line to the top of the ring casting. Payment shall be at the unit bid price for each type and size of manhole properly installed. The unit bid price for manholes shall include all bedding, backfill, compaction and all appurtenances including castings and lids necessary for the proper installation. One of the following methods will be specified:

1. Manhole by Lump Sum: Count the number of new manholes properly installed. Payment will be at the unit price for each type and size of manhole properly installed. The unit price for manholes will include all excavation, bedding, backfill, compaction, concrete, reinforcing steel, and all appurtenances, including chimney seals, castings, and covers, necessary for proper installation.

2. Manhole by Vertical Feet: For new manholes properly installed, count the number of combined base and casting units for each size and type. In addition, measure the manhole vertical dimension in feet from the flowline to the bottom of the casting. Payment will be at the unit price for each combined base and casting unit properly installed. In addition, payment will be made by the unit price for the vertical dimension of the manhole.

B. Drop Connection: Measurement of the drop will be in vertical feet of drop, from the flow line flowline of the incoming sewer to the flow line of the drop at its entry into the manhole, for each size of sewer line. Payment shall will be at the unit bid price for vertical feet of the drop per size of sewer line.

C. Casting Extension Rings: Count the number of existing manhole castings raised with casting extension rings to match the elevation of a pavement overlay. Payment will be made at the unit price for each casting extension.

CD. Manhole Adjustment, Minor: Removal or addition of Mmanhole adjusting rings are considered an incidental item to manholes, unless otherwise specified as a pay item in the contract documents. If specified as a pay item, it shall will be at the unit price bid for each adjustment. If so specified, count the number of manholes adjusted to finished grade by raising or lowering an adjustable casting or by addition or removal of manhole adjusting rings. Whether specified as a pay item or not, new casting is included.

DE. Manhole Adjustment, Major: Count the number of manholes adjusted to grade by addition or removal of manhole barrel riser, cone or flat top sections, or the exchange of existing sections with sections having revised different vertical dimensions. Count separately the cast in place manholes that will require removal of concrete to accommodate adjustment. Payment shall will be at the bid price for each major adjustment. The unit price will include all excavation, bedding, backfill, compaction, concrete, reinforcing steel, and all appurtenances, including the new casting and new chimney seal.

EF. Connection to Existing Manhole: Count the number of connections made to existing manholes. Payment shall will be at the unit bid price for each connection.

FG. Abandoned Manhole: Count the number of manholes abandoned in place. Payment shall will be at the unit bid price for each abandoned manhole. (NOTE: Refer to Section 6020, 3.05 for removal of manholes.)

GH. In Situ Manhole Replacement, Formed-In-Place Concrete: Measurement of the vertical dimension of In Situ Manhole Replacement in situ manhole replacement will be from the manhole invert to the bottom of the frame. Payment shall will be at the unit bid price per vertical foot. Installations for which When a plastic liner is specified, the installation will shall be measured and paid for separately from those without a liner. The unit bid price includes handling of sewer flows as required to properly complete the installation, bench and invert overlay as recommended by the manufacturer, and testing the manhole upon completion. In addition, the unit bid price for installations with a plastic liner includes sealing at the frame and cover and sealing pipe penetrations as recommended by manufacturer.

HI. Manhole Lining with Centrifugally Cast Cementitious Mortar Liner with Epoxy Seal: For each liner thickness specified, measurement of the vertical dimension of manhole lining will be from the bottom of the lining to the top of the lining. Payment shall will be at the unit bid price per vertical foot for each thickness of liner properly installed. The unit bid price includes the handling of sewer flows during lining operations as required to properly complete the installation.

IJ. Install Chimney Seal on Existing Manhole: Count the number of manhole chimney seals installed on existing manholes. Payment shall will be made at the unit bid price for each chimney seal installed.

PART 2 - PRODUCTS

2.01 MANHOLES CONCRETE MANHOLE COMPONENTS

A. Placement: Conform to elevations, locations and connection orientations shown on the Plans and detailed drawings.

A. Cast Concrete:

1. Precast: Comply with ASTM C 478

2. Cast-in-place: See Section 6010.

B. Barrel Diameter, Inside Riser Sections:

1. For sewers up to 24-inch size with two connections use 48 inches diameter barrel or as shown in the contract documents.

2. For larger sewers or more connections, see Plans and detailed drawings.

1. Inside Diameter: Use a 48-inch diameter riser or as shown in the contract documents.

2. Wall Thickness: See Figures 6020.1 through 6020.21. For precast, see ASTM C 478.

3. Coating:

a. Exterior:
1) Sanitary Sewer Manholes: When exterior waterproof coating is specified, provide bituminous or coal tar coating.
2) Storm Sewer Manholes: Exterior coating is not required.
b. Interior:
1) Sanitary Sewer Manholes: When manhole lining is specified, line according to lined, reinforced concrete pipe, Section 4010, 2.01.
2) Storm Sewer Manholes: Interior coating is not required.

4. Riser Joints:

a. Male and female ends.
b. Sanitary Sewer Manhole Joint Sealant:
1) Rubber 'O' ring or profile gasket, flexible joint, per ASTM C 443.
2) Bituminous joint compound or butyl sealant wrap per ASTM C 877 to all exterior joints.
c. Storm Sewer Manhole Joint Sealant:
1) Bituminous Jointing Material: use a cold applied mastic sewer joint sealing compound recommended by the manufacturer for the intended use and approved by the Jurisdictional Engineer. Meet the requirements of AASHTO M 198.
2) Rubber Rope Gasket Jointing Material: Conform to ASTM C 990.

5. Lift Holes: Lift holes not to protrude through manhole wall. Provide non-shrink grout to cover lift hole plug and to fill interior joints.

C. Wall Thickness: See Detail Plates

D. Coating:

1. Exterior

a. Sanitary Sewer Manholes: when exterior waterproof coating is specified, provide bituminous or coal tar coating.

b. Storm Sewer Manholes: none required.

2. Interior

a. Sanitary Sewer Manholes: When manhole lining is specified, line in accordance with lined, reinforced concrete pipe, Section 4010, 2.01 F.

b. Storm Sewer Manholes: none required.

EC. Top Configuration:

1. Eccentric top except as noted on the Plans or detailed drawings.

2. Total manhole depth 6 feet or more use cone top section.

3. Total manhole depth less than 6 feet use minimum 9" thick flat top.

1. Capable of supporting HS-20 loading.

2. Use eccentric cone, unless otherwise specified or allowed.

F. Joints, Barrel:

1. Male and female ends.

2. Sanitary sewer manhole:

a. Seals, rubber 'O' ring or profile gasket, flexible joint, per ASTM C 443.

b. Apply Bituminous joint compound or butyl sealant wrap meeting ASTM C 877 to all exterior joints.

c. Provide tapered rubber lift hole plug manufactured of SBR with a minimum tensile strength of 800 psi and 80 durometer + or –5.

d. Provide non-shrink grout to cover lift hole plug and to fill interior joints.

3. Storm sewer manhole: Mastic seal

G. Concrete:

1. Precast: Comply with ASTM C 478.

2. Cast in place: Refer to Section 6010.

HD. Base:

1. Sanitary sewer system Sewer:

a. Type A (Standard Precast manhole Manhole: Integral base and lower riser section in accordance with according to ASTM C 478.

b. Cast in place manhole All Other Manholes: base riser section embedded at least 3 inches into poured in place base Cast-in-place concrete base.

2. Storm Sewer System:

Use precast or cast-in-place base.

a. Precast manhole: Separate base from riser section. Use with precasted base or poured base.

b. Cast in place manhole: Use with precasted base or poured base.

IE. Pipe Connection:

1. New Sanitary Sewer Manhole:

a. Flexible, watertight gasket per ASTM C 923 cast integrally with riser section(s).

b. Drop Install drop connection where required on Plans the plans. See also Detailed Drawings Figure 6020.6A.

c. When specified, coat interior per 4010 2.01 F.5, 6, 8, 9, and 10.

dc. Grout internal joint space: Use non-shrink grout on internal joint space.

2. New Storm Sewer Manhole:

a. Precast mManholes: factory fabricated Fabricated openings.

b. Poured in place structures Cast-in-Place Structures: sStructure wall poured placed around pipe stub.

3. Existing Sanitary or Storm Sewer Manhole:

a. Cored or dDrilled o Opening: Provide a flexible, watertight connection that meets and/or exceeds ASTM C 923

b. Knock out oOpening: See Figure 6020.21

1) Provide a watertight connection (waterstop or other method), meeting the material requirements of ASTM C 923, that is securely attached to the pipe with stainless steel bands or other means.
2) Grout opening in manhole wall with non-shrink grout.
3) Pour concrete collar around pipe and outside manhole opening.
4) Provide flexible pipe joint or flexible connector within 2' of collar.

4. Existing Storm Sewer Manhole: See Figure 4020.1A.

JF. Manhole Steps:

1. None, unless required on the Plans.

2. If required, space steps at 12 to 16 inches, comply with ASTM C 478. Align with vertical side of eccentric cone top section.

1. Comply with ASTM C 478.

2. Manufactured of polypropylene encased steel.

3. Uniformly space steps at 12 to 16 inches.

4. Align with vertical side of eccentric top section

5. First step no more than 36 inches from top of casing.

G. Manhole Types:

Sanitary
Sewer
Figure
No.
Type Description
6020.1 A 48" minimum diameter riser with eccentric cone and integral precast base
6020.2 E Cast-in-place box
6020.3 F Combination cast-in-place manhole with 48" diameter lower riser and eccentric cone
6020.4 I 48" diameter riser with eccentric cone and castin-place base for manhole placement on existing sewer
6020.5 J 48" diameter riser with eccentric cone and
T-section
Storm
Sewer
6020.12 M-A 48" minimum diameter short cone or flat top with cast-in-place or precast base
6020.13 M-B Precast or cast-in-place box with precast or cast-in-place base
6020.14 M-C Cast-in-place box with cast-in-place base
6020.15 M-D Combination 48" diameter short cone with
cast-in-place riser and cast-in-place base
6020.16 M-E 48" diameter short cone with T-section

2.02 MANHOLE ADJUSTMENT RINGS (Grade rings)

A. All Utilize one of the following methods for grade adjustments of manhole frame and cover assemblies shall be completed utilizing one of the following:

1. Reinforced Concrete Grade Adjustment Rings: Comply with ASTM C 478 and be free from cracks, voids, and other defects. Concrete Set concrete rings will be set with asphalt mastic in trowelable or rope form.

2. High Density Polyethylene Grade Adjustment Rings: Comply with ASTM Standard D 1248 for recycled plastic.

a. Material properties shall be tested and certified for usage by the following ASTM methods:

Property Test Method Acceptable Value
Recycled Plastic ASTM D 1248 N/A
Melt Flow Index ASTM D 1238 0.3 to 30 g / 10 min.
Density ASTM D 792 0.94 to 0.98 g / cm3
Tensile Strength ASTM D 638 2.00 to 5 x 103 lb / in2

b. Polyethylene adjusting rings shall not be used when they are exposed to heated hot mix asphalt pavement.

ca. Tapered configuration: When used in a single configuration tapered Tapered adjusting ring thickness will ranges from 0.5 inch to 3.0 inch 1/2 inch to 3 inches.

db. Grade Install grade adjustment rings are to be installed on clean, flat surfaces according to the manufacturer's recommendations with the proper Bbutyl Rrubber sealant/adhesives.

c. Do not use polyethylene adjusting rings when they are exposed to HMA pavement.

B. The Ensure the inside diameter of the adjustment ring shall is not be less than the inside diameter of the manhole frame.

C. Manholes shall be constructed Construct manholes with at least two one adjustment rings, totaling 4 inches minimum and 12 inches maximum for new manholes and 4 inches minimum and 16 inches maximum for existing manholes.

D. Maximum height of adjustment ring stack: 12 inches max. for new manholes and 16 inches max. on existing manholes.

2.03 CASTINGS (Ring, and Cover, and Extensions)

A. Gray Cast Iron: ASTM A 48, Class 35.

B. Sanitary Sewer Manhole RIng and Covers:

1. Refer to Plans for locations of types.

2. Machined bearing surfaces.

3. All covers must be gasketed.

4. Grassed areas not subject to flooding: Type A.

5. Grassed areas subject to flooding, bolted down cover: Type C.

6. Paved areas, sidewalks, and areas subject to vehicular traffic and not subject to flooding or in sloped paved areas use cover: Type B.

7. Paved areas, sidewalks, and areas subject to vehicular traffic and flooding or in sloped paved areas subject to flooding, use bolted down cover: Type D.

C. Storm Sewer Manhole Ring and Covers:

1. Grassed areas: Type E.

2. Paved areas, sidewalks, areas subject to vehicular traffic and sloped surfaces: Type F.

3. For installation directly into concrete pipe riser manhole, Type G.

4. Bolt all castings set above grade.

5. Storm sewer manhole lids shall not be bolted.

B. Casting Types:

  Figure
No.
Casting
Type
Ring
Cover
Gasket Bolted Cover
(Floodable)
Typical Surface
Sanitary
Sewer
6020.7 A STD Yes1 No Non-paved/flexible2
6020.8 B ADJ Yes1 No PCC3
6020.9 C STD Yes1 Yes Non-paved/flexible2
6020.10 D ADJ Yes1 Yes PCC3
Storm
Sewer
6020.17 E STD No N/A Non-paved/flexible2
6020.18 F ADJ No N/A PCC3
1 Machine bearing surfaces required.
2 Includes HMA, seal coat, gravel, and brick.
3 Includes castings in concrete boxouts.

C. Manhole Casting Extension Ring:

1. Gray cast iron conforming to ASTM A 48, Class 35.

2. Size the extension ring to fit the existing ring and cover.

3. Maximum height of 3 inches.

4. Match the dimensions of the existing ring and cover with an allowable diameter tolerance of -1/4 inch for the frame ridge and +1/4 inch for the cover recess.

5. The height of the extension ring as required to raise the top of the casting to make it level or no more than 1/4 inch below the finished pavement surface.

2.04 CEMENT MORTAR - Refer to Comply with Section 6010.

2.05 REINFORCING STEEL - Refer to Comply with Section 6010.

2.06 CHIMNEY SEAL (Required on all Sanitary Sewer Manholes) (For New Sanitary Sewer Manholes and Sanitary Sewer Manhole Adjustments)

A. External Rubber Seal:

1. Rubber Sleeve and Extension:

a. Corrugated, minimum thickness of 3/16 inches, per ASTM C 923.

b. Minimum vertical unexpanded length of 6 and 9 inches with allowable vertical expansion of at least 2 inches.

c. Top section of sleeve shall contain multiple sealing fins to extend both over and under the manhole frame's base flange. Bottom section of sleeve shall contain an integrally formed compression band recess with multiple slaking fins.

d. Top section of extension to be shaped to fit into the bottom band recess of the sleeve. Bottom section of extension shall contain an integrally formed compression band recess with multiple sealing fins.

c. See Figure 6020.1, sheet 2, for dimensional requirements.

2. Compression Bands:

a. One piece band assembly to compress sleeve or extension against manhole and casting surfaces.

b. Material 16 gauge ASTM A 240, Type 304 stainless steel, minimum 1 inch width, minimum adjustment range of 4 diameter inches more than the manhole outside diameter.

c. Top For standard twopiece castings, top band shaped to lock sleeve to manhole frame's base flange. For three-piece adjustable castings, top band shaped to lock sleeve to upper piece of adjustable frame.

d. Stainless steel fasteners conforming to ASTM F 593 and 594, Type 304.

B. Internal Rubber Seal:

1. Rubber sleeve and extension:

a. Double pleated, minimum thickness 3/16 inch thick, per ASTM C 923.

b. Minimum vertical unexpanded length of 8 and 10 inches with allowable vertical expansion of at least 2 inches.

c. Integrally formed expansion band recess top and bottom with multiple sealing fins.

d. Top section of extension shaped to fit bottom band recess of the sleeve. Bottom section of extension shall contain an integrally formed expansion band recess with multiple sealing fins See Figure 6020.1, sheet 2, for dimensional requirements.

2. Expansion Bands:

a. One-piece band assembly to compress sleeve or extension against manhole and casting surfaces.

b. Material 16 gauge ASTM A 240, Type 304 stainless steel, minimum 1-3/4 inch width, minimum adjustment range of 2 inches more than the manhole inside diameter.

c. Locking mechanism of studs and nuts used to be stainless steel conforming to ASTM F 923 & and ASTM F 594, Type 304.

2.07 INVERT

CA. Bring Construct manhole invert up to one-half of pipe diameter to produce a smooth half pipe shape between pipe inverts. Slope invert bench toward pipe 1/4 inch per foot perpendicular to flow line.

A B. Poured in place concrete. Use a precast invert on all precast base sections, unless otherwise allowed by the Jurisdictional Engineer. See Figure 6020.1

B. Shape to provide a smooth transition between pipe inverts.

2.08 PRECAST CONCRETE TEE

Precast Concrete Tee Pipe Section May Be Used In Lieu Of Standard Manhole Base And Base Riser Section:

1. For sewers 42 inch and larger.

2. Where required on the Plans.

3. Where approved by Jurisdictional Engineer.

2.098 EXISTING MANHOLE REHABILITATION

A. Chimney Seals (Existing For Manhole Rehabilitation):

1. Chimney Seals Rubber chimney seals as specified in Section 6020, 2.06 for new sanitary sewer manholes may be installed on existing manholes.

2. Brush Applied, Corrosion Resistant Aromatic Flexible Urethane Chimney Seal for Existing Manholes:

a. Aromatic flexible urethane seal shall have a minimum of 800% elongation, per ASTM D 412

b. Tensile strength of 1150 psi, per ASTM D 412 and adhesive strength of 175 lb/in, per ASTM D 903

c. Internal seal shall resist 5 feet of head pressure at a minimum thickness of 175 mils

d. Internal seal shall meet ASTM C 1244-93 vacuum test 10 inches at two minutes

e. Flexible aromatic urethane seal shall be brush applied and cover 2 inches above the bottom of the frame and the entire adjustment ring area to 3 inches below the bottom adjustment ring.

Property Test Method Acceptable Value
Elongation ASTM D 412 800%, minimum
Tensile Strength ASTM D 412 1150 psi, minimum
Adhesive Strength ASTM D 903 175 lb/in, minimum
Pressure Resistance ASTM C 1244 2 minutes

B. Manhole Interior:

1. In Situ Manhole Replacement, Formed-In-Place Concrete:

a. Forming System: Provide an internal forming system capable of forming a new and structurally independent manhole wall within the existing manhole, of with the specified thickness, and conforming to the general shape of the existing manhole, within the existing manhole. The assembled internal forms shall be bolted together to prevent shifting and shall have sufficient stiffness and strength to prevent collapse.

b. Concrete: Type I/II Pportland cement concrete with 5/8 inch minus coarse aggregate with fiber reinforcement and water reducer, 4000-psi minimum 28-day compressive strength.

c. Plastic Liner: When specified, provide a PVC or PE plastic liner resistant to degradation by sulfuric acid. The Use a liner shall be capable of being attached to the exterior of the forming system during erection of the forms. The Use a plastic liner shall have with a ribbed or studded exterior surface suitable for anchoring to the newly formed interior wall.

2. Centrifugally Cast Cementitious Mortar Liner with Epoxy Seal:

a. Cementitious Lining:

1) Shall be Use a high strength, high build, corrosion resistant mortar, based on Pportland cement fortified with micro silica. Mixed mortar shall to have a paste-like consistency which that may be sprayed, cast, pumped, or gravity-flowed into any area 1/2 inch and larger.

2) Cementitious Lining shall have Exhibits the following properties:

Property Value
Unit Weight 125 pcf
Set Time at 70°F ASTM C 403
          Initial Set / Final Set

240 minutes / 440 minutes
Modulus of Elasticity ASTM C 469
           
24 hours / 28 days

180,000 psi / 1,150,000 psi
Flexural Strength ASTM C 293
         
24 hours / 28 days

650 psi / 800 psi
Compressive Strength ASTM C 109
         
24 hours / 28 days

3,000 psi / 10,000 psi
Tensile Strength ASTM C 307 600 psi
Shear Bond ASTM C 882 >1,000 psi
Shrinkage ASTM C 157 None
Chloride Permeability ASTM C 1202 <550 Coulombs

3) Shall contain Contains a liquid admixture for the prevention of micro biologically induced corrosion. The admixture shall permeates the mortar during the mixing phase and molecularly bonds to the cement particles, creating an environment incompatible to the growth of bacteria which that may be harmful to concrete.

b. Corrosion Resistant Epoxy Lining:

1) Epoxy lining shall be Consists of a two-component 100% solids epoxy design formulated for use in sewer systems. The epoxy lining shall forms a protective layer impervious to biological corrosion.

2) Physical Properties:

Property

Value
Dry Time 4-6 hours @ 75oF
Compressive Strength ASTM D-695 16,800 psi
Flexural Strength ASTM D-790 13,900 psi
Tensile Strength ASTM D-638 12,400 psi
Hardness ASTM D-2240 68-72 Shore D
Heat Distortion ASTM D-648 220oF
Ultimate Elongation ASTM D-638 4.5%
Adhesive Shear ASTM C-882 1,000 psi

PART 3 - EXECUTION

3.01 MANHOLE INSTALLATION

A. Manhole Chimney

1. Install internal or external rubber chimney seal in accordance with Section 6020, 3.04.

2. Aromatic Flexible Urethane Seal:

a. Surface Preparation shall be in accordance with the manufacturer’s recommendations and shall include sandblasting, pressure washing, sealing leaks or gaps, and drying surface.

b. Apply primer, prepare product and apply in accordance with manufacturer’s recommendations.

A. Excavation: Excavate according to Section 3010.

B. Subgrade Preparation:

1. Undisturbed sSoil: Hand grade to accurate elevation.

2. Disturbed sSoil: Machine compact to 95% percent of maximum Standard Proctor Density and hand grade to accurate elevation or install stabilization material as directed by the Jurisdictional Engineer.

C. Installation of Poured In Place Cast-in-Place Base:

1. Sanitary sewers: embed base riser in base slab 3 inches, minimum.

2. Storm sewers: bed base riser section in Class C concrete.

1. Excavate and prepare subgrade to the required elevation to accommodate the cast-in-place base.

2. Plae Class C concrete base as specified.

3. Embed lower riser section in base concrete a minimum of 3 inches.

34. Assure Ensure proper vertical and horizontal alignment of base riser section.

D. Installation of Precast Base with Base Riser Section: Assure proper vertical and horizontal alignment of base riser section.

1. Excavate and prepare subgrade to the required elevation to accommodate the aggregate subbase.

2. Place aggregate subbase as specified.

3. Place base with lower riser section and ensure vertical and horizontal alignment.

E. Additional Risers Sections: Install additional riser sections as required. Grout inside face of joints.

F. Repairs: Repair any honeycomb areas or damaged areas as directed by the Jurisdictional Engineer.

G. Backfill up to pipe grades Pipes: Connect and bed pipes using bedding material up to one foot above top of pipes Install and bed pipes. Place bedding and pipe embedment material according to Section 3010.

H. Sanitary sewers Lift Holes: Grout inside pipe/manhole joint. Install For sanitary sewers, install rubber plug and grout over manhole lift holes.

I. Install manhole invert Manhole Invert: Install manhole invert if not precast. Remove If precast, remove any projections and repair any voids to assure ensure a hydraulically smooth channel between pipe ends.

J. Install manhole top slab or cone. Top Sections: Install manhole cone or flat top section.

K. Install manhole adjustment rings. Manhole Adjustment Ring(s): Bed each concrete ring with cold-applied bituminous jointing compound. Bed each polyethylene ring with manufacturer's approved product. Do not install more than total ring stack height of 12 inches. Use a minimum stack height of 4 inches and a maximum adjustment ring stack height of 12 inches. For greater adjustment, modify barrel lower riser section(s).

L. Install manhole ring and cover. Manhole Ring and Cover: Adjust accurately Install manhole ring and cover and accurately adjust to proper grade. Where manhole is to be in a paved area, adjust slope to match finished surface. See Figures 6020.7 - 6020.10 and 6020.17 - 6020.19.

M. Install chimney seal: Install chimney seal per manufacturer’s recommendations on sanitary sewer manholes.

M. Chimney Seal: For sanitary sewer manholes, install internal or external rubber chimney seal meeting the requirements of Section 6020, 3.04.

N. Seal Manhole Joints Joint Sealant: Apply bituminous joint compound or butyl sealant wrap to exterior of sanitary sewer manholes joints. If required, apply engineering fabric wrap meeting the requirements of Iowa DOT 4196.01B to storm sewer manhole joints.

O. Backfill and compact. Compaction: Refer to Place backfill and compact per Section 3010. Use extra care to assure ensure proper and uniform compaction of backfill around structure.

3.02 CONCRETE, REINFORCEMENT, AND PLACEMENT - Refer to Comply with Section 6010

3.03 MODIFICATION OF EXISTING MANHOLES

A. Minor Adjustment: adjustment by adding or removing adjusting rings:

A. Casting Extension Rings: Install and adjust for proper alignment.

B. Minor Adjustment (adding or removing adjusting rings):

1. Remove casting.

12. Add adjustment rings if necessary, up to a total ring stack As necessary, add a maximum height of 16 inches of adjustment rings to adjust existing manhole to finished pavement grade or finished topsoil grade. Bed each concrete ring with cold applied bituminous jointing material. Bed each polyethylene ring with manufacturer's approved product.

23. Remove one or more adjustment rings, as appropriate, to reduce casting elevation.

34. Replace castings. Install new frame and cover for manholes located within new full depth pavement: use adjustable frame and cover as specified on modified adjusting ring.

45. Replace chimney seal for sanitary sewer manholes using only new materials.

56. Refer to See Sections 7010 and 7020 for additional manhole adjustment requirements in pavement.

BC. Major Adjustment (adding or removing riser or cone sections): adjustment by adding or removing barrel or cone sections

1. Remove castings casting.

2. Remove top.

3. Modify barrel Remove and replace riser section and/or modify type of top section, as appropriate, or both.

4. Replace castings casting. Install new frame and cover for manholes located within new full depth pavement. Use an adjustable frame and cover as specified.

5. Fasten manholes to castings with bolts.

56. Replace chimney seal for sanitary sewer manholes using only new materials.

CD. Connection to Existing Manhole: Unless otherwise specified in the contract documents, or approved by the Jurisdictional Engineer, core all new openings in existing manholes shall be cored.

1. Excavate as appropriate. Mark manhole barrel riser for point of insertion of added sewer line.

2. Divert flow as necessary. Obtain approval of the diversion plan from the Jurisdictional Engineer. Maintain sewer service at all times unless otherwise permitted by the Jurisdictional Engineer.

3. Carefully cut and chip or core out opening to manhole. Remove existing manhole invert as necessary to install pipe at required elevation and develop hydraulic channel.

4. Cored oOpening:

a. Insert flexible watertight connector into new opening.

b. Install and tighten internal expansion sleeve to hold flexible connector in place.

c. Insert pipe through flexible connector and tighten external compression ring.

d. Do not grout opening or pour collar for cored opening with flexible connector.

5. Cut and cChipped oO pening (kKnockout): When allowed, refer to Figure 6020.21

a. When allowed, refer to Figure 6020.21

ab. Install waterstop around outside of pipe. Secure in place.

bc. Position end of pipe flush with interior wall of manhole and with waterstop located within wall opening.

cd. Grout opening between manhole wall and outside of pipe with non-shrink grout.

de. Pour concrete collar around pipe and exterior manhole opening as shown on Figure 6020.21.

6. Reconstruct manhole invert.

7. Bed pipe and place backfill per Section 3010.

3.04 CHIMNEY SEALS (Required on All Sanitary Sewer Manholes)

A. Install internal chimney seal if manhole is to be under pavement or, if not under pavement, is set more than 3 inches above final grade or subject to movement.

A. Install chimney seals on all sanitary sewer manholes.

B. Rubber Chimney Seals (see Figure 6020.1, sheet 2):

B1. Install Do not install external chimney seal if manhole is not to be under pavement except as noted in 3.04 A is exposed to sunlight.

C2. Install seals on a smooth sealing surface. Seals to extend from the flange of the manhole frame to 3 inches below the adjusting ring, use multiple seals, if necessary. Install compression bands (external chimney seal) or expansion bands (internal chimney seal) to lock the rubber sleeve or extension into place and to provide a positive watertight seal. Once tightened lock into place. (See Figure 6020.1, Sheet 2 of 2) Use only manufacturer recommended installation tools and sealants.

3. All seals extend to 3 inches below the lowest adjusting ring.

4. For standard two-piece castings, seals to extend 2 inches above the flange of the casting. For adjustable three-piece castings, seals to extend 2 inches above the top of the base section of the casting.

5. Use multiple seals, if necessary.

6. Install compression bands (external chimney seal) or expansion bands (internal chimney seal) to lock the rubber sleeve or extension into place and to provide a positive watertight seal. Once tightened, lock the bands into place. Use only manufacturer recommended installation tools and sealants.

C. Flexible Urethane Seal:

1. Use only for manhole rehabilitation, if specified.

2. Prepare the surface according to the manufacturer's recommendations, including sandblasting, pressure washing, sealing leaks or gaps, and drying surface.

3. Apply primer, prepare product, and brush apply a flexible urethane seal to a minimum thickness of 175 mils, covering 2 inches above the bottom of the frame and the entire adjustment ring area to 3 inches below the bottom adjustment ring.

3.05 ABANDONED MANHOLES

A. Remove Unless otherwise specified, remove top and walls of structure to a minimum of 10 feet below subgrade in paved areas or 10 feet below finish grade in other areas.

B. Plug all pipes in structure using 3,000-psi concrete.

C. Fill remaining structure using flowable mortar per Section 3010.

D. Place compacted earth fill over structure as required for embankment or compacted backfill.

3.06 MANHOLE TESTING - Refer to Section 6040. Comply with Section 6040.

3.07 MANHOLE REHABILITATION

A. Manhole Chimney: Install manhole chimney seal according to Section 6020, 3.04.

1. Install internal or external rubber chimney seal in accordance with Section 6020, 3.04

2. Aromatic Flexible Urethane Seal

a. Surface Preparation shall be in accordance with the manufacturer’s recommendations and shall include sandblasting, pressure washing, sealing leaks or gaps, and drying surface.

b. Apply primer, prepare product and apply in accordance with manufacturer’s recommendations.

B. Manhole Interior

1. In Situ Manhole Replacement, Formed-In-Place Concrete: Prepare, install, and test in accordance with according to forming system manufacturer's recommendations including the following items.

a. Preparation:

1) Clean existing surface to remove loose material and debris.
2) Remove existing steps that might interfere with the erection of the forms.
3) Control infiltration which that may affect placement of concrete.

b. Installation:

1) Place pipe extensions through structure to maintain flow during installation.
2) Erect forms inside manhole. Include plastic liner when specified.
3) Bolt the assembled internal forms together to prevent shifting and provide sufficient stiffness and strength to prevent collapsing.
34) Seal forms at the bottom of the manhole to ensure the concrete does not enter the sewer.
45) Carefully place concrete between forms and existing manhole walls. Place concrete from bottom up
in such a manner to prevent segregation of concrete.
56) Consolidate concrete as required to fill all pockets, seams, and cracks within the existing manhole wall.
67) Remove forms when the concrete has cured sufficiently.
78) If a plastic liner is installed, weld and test any joints.
89) Apply a sealing strip around circumference of the invert bench where it meets the vertical wall and around all pipe penetrations, to form a waterstop.
910) Overlay the invert bench with concrete or high strength mortar at a thickness of 3 inches at the wall, tapering to ˝' 1/2 inch at the edge of the invert.
1011) Apply a 100% solids solid epoxy to the invert bench for corrosion resistance. Apply clean sand to the epoxy to create a non-slip surface.
1112) Plastic Seal the plastic liner shall be sealed to the manhole casting and existing pipe stubs as recommended by the manufacturer.

2. Centrifugally Cast Cementitious Mortar Liner with Epoxy Seal:

a. Surface Preparation: Surface preparation shall be in accordance with Prepare the surface according to the manufacturer's recommendations, including and shall include washing the interior with a high‑pressure washer and plugging any active leaks with the appropriate plugging sealing material.

b. Mortar Application: Shall be applied in accordance with Apply according to the manufacturer's recommended procedures including the following items:

1) Apply with a rotating centrifugal casting applicator, beginning at the bottom of the manhole.
2) Retrieve the applicator head at the manufacturer's recommended speed to achieve the desired thickness.
3) Apply to full required thickness utilizing multiple passes as necessary. Time Minimize the time between passes shall be minimized so that subsequent passes are cast against fresh mortar.
4) Verify thickness with a wet gage at several locations to ensure proper depth.
5) Brushing the mortar after application to improve adhesion is optional.
6) Hand apply additional material to the invert bench surface at a thickness of 3 inches, tapering from the wall to the edge of the channel.

c. Epoxy Seal Application: Shall be applied in accordance with Apply according to the manufacturer's recommended procedures including the following items:

1) Apply with rotating centrifugal casting applicator or airless sprayer onto the fresh mortar liner.
2) If epoxy seal is applied more than 24 hours after application of the mortar lining, or if the mortar lining is exposed to foreign matter, it shall be rinsed rinse to neutralize its surface and the epoxy shall then apply the epoxy be applied.

END OF SECTION