RFP 7061 Addendum No. 1
Job no hazenandsawyer.com
Hazen and Sawyer
8150 N. Central Expressway
Dallas, TX 75206 • 214.382.5750
August 28, 2019
Jane Rogers, MPA, CPBFM
Senior Buyer
City of Denton Purchasing Department
901 B Texas Street
Denton, TX 76209
Re: RFP 7061 Hickory Creek Detention Facility and Pecan Creek WRP West Peak Flow Pump
Station Response to Bidder Questions and Addendum No. 1
Responses to bidder questions are in bold below:
1. Is there a geotechnical report available?
Yes. The geotechnical investigation report will be posted to the City of Denton Purchasing
Website along with Addendum No. 1 for information purposes.
2. Would displacement piles be considered as alternate?
Displacement piles will not be considered as an alternate, bid as shown in the Contract
Documents.
3. Do you have a planholders list available?
Per City of Denton Purchasing Department; a plan holders list is not available.
4. Multiple questions:
a. Specification Section 01400 1.01.A.1 States that the Owner is responsible for all
laboratory testing unless otherwise specified. Please confirm that all concrete, shotcrete,
and other related material testing, pertaining to the 3.50MG tank will be paid for by the
Owner.
For testing see specification section 01400 and quality control or testing criterial in
each material specifications. In general, materials will be tested by a testing agency
employed by the owner; however additional tests, supplemental tests, preproduction
tests, and other tests as defined in the specifications are to be paid by the
Contractor.
b. Specification Section 03350 Article 2.01A references a “Concrete Sealer” to be used on
concrete slabs or floors. Please confirm that the 3.50MG Water Storage Tank does not
have a requirement for a concrete floor sealer.
Confirmed. Specification Section 3.03.C states sealers are not to be applied to
surfaces which will be immersed.
c. Specifications 03350-6, Concrete Finishes, Concrete Finish Schedule, Please confirm the
following AWWA D110 standard finishes are acceptable for the 3.5 MG Storage Tank:
• The floor slab shall receive a bull float finish or Fresno finish. The top of the wall
footing, exterior to the waterstop, shall receive a steel trowel or magnesium trowel
finish.
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• The interior of the precast wall panels shall receive a light broom finish.
• The exterior of the dome shall receive a light broom finish. The interior of the dome
shall receive a form finish.
• Exterior shotcrete shall receive a natural gun / nozzle finish.
Confirmed. See addendum changes below.
d. Specifications 13205-7, Prestressed Concrete Tank, 2.02 Concrete, It is stated “Concrete
for the tank wall and dome construction shall have a minimum compressive strength of
4,500 psi at 28 days.” However in Section 03400-3, Precast Concrete, 2.01 Concrete,
Article B, states all prestressed concrete items shall have a minimum compressive
strength of concrete of 5,000 psi. Please confirm a concrete strength of 4,500 psi as stated
in the tank specifications is acceptable.
Confirmed, specification Section 03400 states unless otherwise specified in the
referenced article above, therefore the 13205 specification would apply.
e. Specifications 13205-4, Prestressed Concrete Tank, 1.04 Information Furnished by
Owner, Article A Item 14. Please confirm the following decorative exterior coatings are
acceptable for the roof and walls for the prestressed concrete tank.
Decorative coating shall be applied to the exterior dome surface using one coat of a
cementitious based damp-proofing product such as “Tamoseal” or equal, and one coat of
a non-cementitious, high build, 100 percent acrylic resin polymer such as “Tammscoat
Smooth” textured protective coating or equal. A decorative coating shall be applied to
the exterior wall surfaces using two coats of a non-cementitious, high build, 100 percent
acrylic resin polymer such as “Tammscoat Smooth” textured protective coating or equal.
Confirmed. See addendum changes below.
f. Specifications 13205-11, Prestressed Concrete Tank, 3.03 Core Wall, Article D, states
that the core wall thickness at top of the tank wall must be a minimum of 8”. Please
confirm that the final core wall design may be sized by the tank mfg according to
AWWA D110-13 Standards.
Confirmed, the core wall is to be sized by the tank manufacturer and meet or exceed
the minimum thickness listed in AWWA D110-13. See addendum changes below.
g. Contract Drawing Sheet S-HC-03, Calls the Drain shall be 30” diameter. Please confirm
the DIP Drain will be 12” as shown in the rest of the contract drawings.
Correct, the DIP drain shall be 12-inches; see addendum changes below.
h. If available, please provide any related geotechnical report or studies for this project.
The geotechnical investigation reports will be posted to the City of Denton
Purchasing Website along with Addendum No. 1 for information purposes.
i. Drawing S-HC-04 – Would a HDPE void form retainer be considered as an alternative to
the 12” turn down slab at the perimeter of the tank foundation?
HDPE void form retainers will not be considered as an alternate, bid as shown in
the Contract Documents.
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5. Per drawing E-HC-10 RTU panels PLC-HCDF and PLC-WPF will communicate to the existing
main panel. Is there an antenna existing antenna/radio infrastructure to communicate to? If so,
other than programming does anything need to be physically changed?
There is existing infrastructure at the plant to allow for communication. The City will be
responsible for modifications to the existing HMI software at the plant. See Section
17000.1.02.C.
6. Has there be a radio site survey performed for these sites?
Yes, the City preformed a radio path study and provided elevation requirements for the
communication towers shown on the Contract Documents.
7. Who is responsible to provide power to RTUs?
Reference panel schedules on Drawings E-HC-10 and E-PC-06 for power source and
Drawings E-HC-13 and E-PC-09 for conduit and wire requirements.
8. Should there be displays on RTU panel?
No OITs (Operator Interface Terminals) shall be provided on RTU panels.
9. Also, can you clarify the class of ductile iron pipe required. Pipe Schedule says Pressure Class
150 and Class 53 for both exposed and buried pipe. Pressure class (150 psi to 350 psi) is usually
buried and class 53 is usually exposed.
See addendum changes below.
10. Please provide the dampproofing and waterproofing specs referenced in the contract documents
(Specifications 07100 & 07150).
The reference in Section 09900 is not applicable to this project and has been removed. See
addendum changes below.
11. C-HC-03 references detail 0227011R for the swale. Is the top image of detail 0227011 on C-D-
02 what the “R” is referring to?
The “R” has been removed from the detail reference callout on C-D-03. See addendum
changes below.
12. Does the contractor have to stay within the limits of disturbance shown on the plans? The
diversion structure at Hickory Creek is shown to be right on the limit of disturbance line. Based
on the depth and location of that structure, if the excavation were to be sloped, the cut area would
be outside of the limits of disturbance. Would this suffice or should a shoring system be utilized
in order to stay within the limits of disturbance?
The limits of disturbance are shown as an approximation of the minimum area estimated to
be disturbed. In the area near the diversion structure, the Contractor must not disturb
areas outside the City of Denton’s existing easement or property line (whichever is least
restrictive). Excavation and sloping is acceptable. The Contractor is required to mitigate
areas within the Environmentally Sensitive Areas as shown in the Contractor Documents.
13. There is no direct mention in the drawings or specifications for coating of the submerged concrete
structures, so am I to assume that all new concrete structures will get coatings on the floors, walls
and ceilings per product #109 on table 9-2?
Provide per the Contract Documents, no coatings are required on new submerged concrete
structures. The drawings do not callout coatings for concrete and there are no concrete
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surfaces where the opposite side of a wet area is interior and dry nor any containment
liners.
14. What is the estimated cost range for this project?
An estimated cost will not be provided.
15. Can you please post the Sing in sheet for the pre-bid conference?
The sign-in sheet will be posted to the City of Denton Purchasing Website with this
addendum.
16. I respectfully request that direct “Roll Grooving” be approved please reference section 15012.
Part 2.01 – E Grooved Mechanical Coupling Joints.
An allowance for roll grooving has been added to the specification. See addendum changes
below.
17. Review and inclusion of the following manufacturer and valve as a named manufacturer:
a. Val-Matic C504 butterfly valve as a named manufacturer in Section 15101 specification.
Added, see addendum changes below.
b. Val-Matic C508 Surgebuster check valve as a named manufacturer in Section 15105
specification. The Surgebuster is the original design of the flapper valve, and the only
manufacturer that carries a 25 year warranty on the flexible portion of the disk.
Added, see addendum changes below.
c. Val-Matic C517 plug valve as a named manufacturer in Section 15109 specification.
Not included as a named manufacturer.
d. J&S Valve C509/C515 gate valve as a named manufacturer in Section 15108
specification.
Added, see addendum changes below.
e. Elite C520 Knife Gate as a named manufacturer in Section 15108 specification
Added, see addendum changes below.
18. What is the duration of this project?
The estimated construction duration is 18 to 24-months from the date of notice to proceed
but will be further evaluated/established with the awarded Contractor’s detailed schedule
submittal.
19. Summary of work paragraph 1.07 time of work states that we will be charged additional money if
we work beyond eight hours per day. What is the hourly rate for these charges. Our normal work
day is between nine and ten hours per day.
See changes in this addendum for total limit on working hours from 40 to 50 hours per
week. This paragraph states that the Contractor may elect to work beyond these hours or
on the weekends and “all costs incurred by the Owner for additional engineering shall be
borne by the contractor”. The additional engineering is in reference to the City’s
engineering department staff, which are not required to be onsite for the Contractor’s
Work at all time but would be called to the site for specific coordination requirements
which are anticipated to be scheduled during normal business hours. This clause does not
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include City inspection staff who will work with the Contractor on schedule except for
Sundays. The Contractor shall not schedule activities that require City inspections on
Sundays due the City’s limitations and requirements for City Council approval.
20. Are the check valves 250lb or 150 lb rated?
A minimum working pressure of 150 psi is acceptable. See addendum changes below.
21. Sheet C-HC-04
a. 3”-PD-PVC or 6”-PD-PVC or where does it change?
The 3”-PD changes to 6”-PD at the tee identified on C-HC-04A Point #39. This
location corresponds to the 6”-PD shown on M-HC-04 from the Odor Control Pad.
b. What is the callout for 4”-PD-PVC?
See addendum drawing changes below.
c. Can you provide a spec and details for the backflow preventer?
See addendum changes below.
22. Sheet C-HC-07 Can you provide details for this size manhole? Can they be tee base fiberglass?
Detail and specification included for a fiberglass manholes. See addendum drawing changes
below.
23. Sheet C-HC-11
a. What spec, size and detail for the Air & Vacuum Release Valve at STA 6+52.51?
See addendum drawing changes below.
b. Is this 16”, 24” or something else (referring to the steel casing pipe)?
The steel casing pipe shall be a minimum 16” diameter and no larger than 24”
diameter. The size shall be selected by the Contractor based on equipment and
methods elected to perform the Work.
24. Sheet C-PC-04
a. Is the existing 42”-RS-RCP C-76 RCP, C-303 bar wrapped cylinder pipe or prestressed
concrete cylinder pipe?
The record drawing information identifies the material of the existing 42-inch as
RCP without further detail. The City installed a manway tee on this pipe in 2017.
The Forterra shop drawing indicates the pipe is concrete steel cylinder pipe. The
Fortera detail is provided as an attachment for information purposes only. The
detail identifies the O.D. as 46-inch but was revised to approximately 45.4-inches.
The Contractor is responsible for field verification and investigation of the existing
line at the tap location for this project prior to the installation.
b. Is the tap on the existing 42”-RS-RCP a wet tap? If so, it cannot be tapped through a plug
valve.
The tap on the existing 42”-RS-RCP is intended to be a “wet tap”. The valve has
been changed to a knife gate valve to allow for a “wet tap”. See addendum changes
below.
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c. One more question with regard to the connection of the new force main to the existing
42” RCP shown on C-PC-04. As noted in our previous question you can’t use a plug
valve as a tapping valve if this is a wet tap. If this is a “dry” tap we could put a flanged
outlet saddle on the existing pipe and then a flanged plug valve. You specified this plug
valve to have a motor operator. Can you provide a detail? Is this valve and motor in a
vault or does it have an extended bonnet with the operator above ground?
Per response to previous question; this valve type has been changed to a knife gate
valve. The intent is for this valve buried with an extended bonnet and operator
above ground. See addendum changes below for details.
25. Sheet M-HC-01
a. BOTOM PLAN. Section E says the 12”-PD-PVC is DI, which is correct? If DI, is it
flanges per Pipe Schedule?
See addendum drawing changes below. DIP is per Pipe Schedule.
b. TOP PLAN. Drawing markup received is pointing to the 4”-NPW-DIP with the question
“What are these?”.
It appears the question is directed at the 22.5° bend fittings that will be required to
keep the pipe running along the curvature of the dome tank. The location is
approximate.
26. Sheet M-HC-04
a. The 6” PD is called out as CPVC but there is no spec for CPVC nor is it shown in Pipe
Schedule.
PD shall be PVC; see addendum drawing changes below.
b. Specification is needed for a 4” pressure regulating valve.
Specification added to 15114. See addendum changes below.
27. Sheet M-HC-08. Additional details required on type of floor drain.
Details added, see addendum changes below.
28. Sheet M-PC-01. Is the triangle on the end of the pipe an in-line check-valve?
Yes, this is an in-line check valve. See addendum drawing changes below.
29. Sheet M-PC-02
a. The combination air valve is drawn as an ARI valve but they are not listed in the specs as
an acceptable manufacturer. Does this require an isolation valve?
Provide a combination air valve per Specification 15114 - 2.04. An isolation valve is
required; see addendum changes below.
b. Fabricated Pipe Support 1509409 is for flange connection. Is the desire to add flanges on
the pipeline at all these locations?
Correct, provide as described in the Contract Documents.
30. Sheet C-PC-03REUSE METER VALUT PLAN. Is a tapping valve required?
Yes, provide a 6-inch tapping gate valve; see addendum changes below.
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31. Will the bid opening date be extended?
Yes, the bid opening has been extended to September 10, 2019. See addendum changes
below.
ADDENDUM CHANGES TO THE CONTRACT DOCUMENTS:
• The Bid Opening Date is extended to September 10, 2019 at 11:00am local time.
• Sheet C-HC-03. Replace detail number "0227011R " on the Diversion Swale callout with
"022701".
• Sheet C-HC-04. Delete 4"-PD-PVC callout.
• Sheet C-HC-11. Replace "AIR & VACUUM RELEASE VALVE - TYPE 2" on callouts at
STA 2+86.29 and STA 6+52.51 with "2-INCH AIR & VACUUM RELEASE VALVE - TYPE
I SEE DETAIL W802 ON C-D-04A" in plan view. Replace "TYPE 2" with "TYPE 1" in
profile callouts.
• Sheet C-HC-07. Replace "W/ WATERTIGHT COVERS" on callouts at STA 3+35.06 and
STA 4+00.25 with "FRP MH W/ WATERTIGHT COVER AND VENT".
• Sheet S-HC-01. Add Detail 9 per ATTACHMENT NO.1 enclosed.
• Sheet S-HC-03. In Bottom Plan view, Replace “PENETRATION FOR 30” DIP DRAIN” with
“PENETRATION FOR 12” DIP DRAIN, SEE MECH DWGS”
• Sheet M-HC-01. Replace "12"-PD-PVC" callout In the BOTTOM PLAN with "12"-PD-DIP".
• Sheet M-HC-04. Replace "CPVC" with "PVC" on all PD callouts.
• Sheet M-HC-06. PUMP STATION TOP PLAN Replace " FABRICATED PIPE SUPPORT
(TYP) 1509409” with “ADJUSTABLE SADDLE PIPE SUPPORT (TYP) 1509405R”.
• Sheet M-HC-07. SECTION A Replace " FABRICATED PIPE SUPPORT (TYP) 1509409”
with “ADJUSTABLE SADDLE PIPE SUPPORT (TYP) 1509405R”.
• Sheet C-PC-03. Add a tapping sleeve knife gate valve to the 6"-NPW-PVC at the tapping
sleeve flange.
• Sheet C-PC-03. Add Detail 1 per ATTACHMENT No. 4 enclosed.
• Sheet C-PC-07. Replace the 36" Plug Valve shown at STA 4+28.53 with a Knife Gate Valve.
Replace all "Plug Valve" callouts associated with the 6" Plug Valve with "Knife Gate Valve".
• Sheet M-PC-01. Add callout to the triangle check valve symbol "SLIP-IN INLINE CHECK
VALVE SERIES CMUF-SL CHECKMATE ULTRAFLEX VALVE BY TIDEFLEX
TECHNOLOGIES OR EQUAL."
• Sheet M-PC-01. PUMP STATION TOP PLAN Replace text pointing to the 14"-PD-DIP "
PIPE SUPPORT (TYP)” with “ADJUSTABLE SADDLE PIPE SUPPORT (TYP) 1509405R”.
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• Sheet M-PC-02. Add an isolation gate valve between the 36"-RS-DIP tee and the 6"
Combination Air Valve.
• Sheet C-D-03. Add Detail 1 per ATTACHMENT NO. 2 enclosed.
• Sheet C-D-04A. Add Detail 1 per ATTACHMENT NO. 3 enclosed.
• Sheet M-D-09. Add "JOSAM 32120, JAY R SMITH 2350, ZURN Z-611, OR EQUAL" to
end of the callout "FLOOR DRAIN WITH SEDIMENT BUCKET AND ADJUSTABLE
TOP".
• Specification 01010. Paragraph 1.07.A Replace "40 hours" with "50 hours".
• Specification 01010. Paragraph 1.07.A.1. Add the following sentence to the end of the
paragraph " Daily rates will depend on the number and classifications of engineering
employees involved, but in no case shall such charges exceed $600 per day for engineering
personnel, based on an eight hour workday."
• Add Specification 02083 Fiberglass Manholes.
• Specification 09900. Table 9-1, Delete the following rows:
Exterior masonry cavity walls
on cavity face of inner wythe
All new structures Dampproofing See Section 07150
Exterior below grade if interior
is dry
Accessible areas (e.g. pipe
galleries, pump rooms,
basements, etc.)
Waterproofing See Section 07100
• Specification 13205. Add paragraph 3.03.I, “I. The interior of the precast wall panels shall
receive a light broom finish. The exterior of the dome shall receive a light broom finish. The
interior of the dome shall receive a form finish."
• Specification 13205. Section 2.10, Replace “COATINGS (NOT USED)” with “COATINGS”
• Specification 13205. Section 2.10, Add paragraph A “A. Decorative coating shall be applied
to the entire exterior dome surface using one coat of a cementitious based damp-proofing
product such as “Tamoseal” or approved equal, and one coat of a non-cementitious, high build,
100 percent acrylic resin polymer such as “Tammscoat Smooth” textured protective coating or
approved equal. A decorative coating shall be applied to the entire exterior wall surfaces using
two coats of a non-cementitious, high build, 100 percent acrylic resin polymer such as
“Tammscoat Smooth” textured protective coating or approved equal. Surface preparation and
application of coatings shall be in conformance with specification section 09900 and per the
manufactures recommendations.”
• Specification 13205. Section 3.03 Core Wall, Article D, Replace (first sentence) “Core wall
thickness at the top of the tank shall be not less than 8-inches.” with “Core wall thickness at
the top of the tank shall be not less than 4-inches.”
• Specification 15012. Section 2.01.E. Replace paragraph E with the following: "Grooved
mechanical coupling joint pipe and fittings shall be split type, shouldered or grooved end.
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Couplings shall consist of a wide EPDM elastomer pressure responsive gasket, and zinc
electroplated carbon steel track head bolts and nuts conforming to the physical and chemical
requirements of ASTM A-449 and the physical requirements of ASTM A-183. Couplings shall
be as manufactured by Victaulic Company of America W07 AGS Rigid Coupling, or equal.
The following styles shall be used by application:
1. Ductile Iron Pipe; Victaulic Style 31
a. Consist of two ASTM A-536 ductile iron housing segments
b. Style 307 transition coupling for direct connection between ductile iron pipe and
steel pipe.
c. Style 341 grooved flange adapter
2. Steel pipe:
a. 12 inches and smaller: Victaulic Style 107N (Rigid) and Style 177 (flexible)
b. 14 inches and larger: AGS series two-segment couplings with lead in chamfer on
housing key and wide-width FlushSeal gasket. Victaulic Style W07 (rigid) and
Style W77S (flexible)"
• Specification 15101. Section 2.01.A. Add "Val-matic," after "DeZurik".
• Specification 15105. Section 2.01.A. Replace "250 psi" with "150 psi" and Add "Val-matic,"
after "Crispin".
• Specification 15108. Section 2.01.B. Add "J&S Valve C509/C515," after "Mueller A-2361".
• Specification 15108. Section 2.02.A. Add "Elite C520," after "DeZurik".
• Specification 15114. Section 2.03. Delete "SMALLER THAN 3-INCH"
• Specification 15114. Section 2.03.A Replace "Febco Model 825Y" with "Febco Model 850".
• Specification 15114. Section 2.03.A Replace "Febco Model 825Y" with "Febco Model 850".
• Specification 15114. Add Section 2.07 as follows:
"2.07 PRESSURE REDUCING AND REGULATING VALVES
A. Pressure reducing and regulating valves (water service) 1/2-inch and under shall be bronze
and above 1/2-inch shall have cast iron bodies bronze fitted. Valves shall be constructed with
full openings and capable of supplying a full flow of water at reduced pressure. Valves shall
be so constructed that repairs can be made without removing the valves from the line. The
valves shall be equipped with a sedimentation chamber and stainless steel or bronze strainer.
Pressure reducing and regulating valves shall be the back pressure sustaining type and shall
operate over a range at differential pressures from 5 to 120 psi. Reducing and regulating
valves shall meet or exceed the requirements of ASSE 1003 (ANSI A112.26.2) and shall be
Model 616R, as manufactured by Fisher Controls, WATTS Series 25 AUB, GA, or equal."
• Specification 15390. Piping System Schedule on page 3 in RS (Raw Sludge) row. Delete
"Class 150," from the DIP (EXPOSED), FLANGED row and Delete "Class 53" from the DIP
(BURIED, RESTRAINED MECHANICAL JOINT row.
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• Specification 15390. ELECTRICALLY OPERATED VALVE SCHEDULE on page 5. For
valve tag 3210 Replace "PLUG" with "KNIFE GATE".
Very truly yours or other closing,
Brandt Miller, PE
Associate
City of Denton Hazen and Sawyer
08/27/2018 Addendum No. 1 02083-1 Fiberglass Manholes
SECTION 02083
FIBERGLASS MANHOLES
PART 1 -- GENERAL
1.01 THE REQUIREMENT
A. Provide all labor, equipment, materials and services necessary for the manufacture,
transportation and placement of all Fiberglass Manholes, as shown on the Drawings or as
ordered by the Engineer.
1.02 MEASUREMENT AND PAYMENT
A. Unit Prices
1. Payment for fiberglass manholes is on unit price basis for each manhole installed
1.03 REFERENCE SPECIFICATIONS, CODES AND STANDARDS
A. Without limiting the generality of the Specifications, all work herein shall conform to or
exceed the applicable requirements of the following documents. All referenced
specifications, codes, and standards refer to the most current issue available at the time of
Bid.
1. ANSI B 16.1 - Cast Iron Pipe Flanges and Flanged Fittings.
2. ASTM A 307 - Standard Specification for Carbon Steel Bolts and Studs,
60,000 psi Tensile Strength.
3. ASTM C 270 - Standard Specification for Mortar for Unit Masonry.
4. ASTM C 1107 - Standard Specification for Packaged Dry, Hydraulic-Cement
Grout (Non- shrink).
5. ASTM D 698 - Standard Test Method for Laboratory Compaction
Characteristics of Soil Using Standard Effort (12,400 ft-lb/ft3 (600kN-m/m3).
6. ASTM D 2665 - Standard Specification for Poly (Vinyl Chloride) (PVC)
Plastic Drain, Waste and Vent Pipe and Fittings.
7. ASTM D 2996 - Standard Specification for Filament-Wound “Fiberglass”
(Glass-Fiber- Reinforced Thermosetting-Resin) Pipe.
8. ASTM D 2997 - Standard Specification for Centrifugally Cast “Fiberglass”
(Glass-Fiber- Reinforced Thermosetting Resin) Pipe.
City of Denton Hazen and Sawyer
08/27/2018 Addendum No. 1 02083-2 Fiberglass Manholes
9. ASTM D 3753 - Standard Specification for Glass-Fiber-Reinforced Polyester
Manholes and Wetwells.
10. American Association of State Highway and Transportation Officials (AASHTO).
1.04 SUBMITTALS
A. Submit the following in accordance with Section 01300, Submittals.
1. Design and fabrication details of fiberglass manhole components
2. Installation instruction for fiberglass manholes
3. Frames, grates, rings, and covers
4. Materials to be used in fabricating drop connections
5. Materials to be used for pipe connections at manhole walls
6. Materials to be used for stubs and stub plugs, if required
7. Plugs to be used for sanitary sewer hydrostatic testing
8. Manufacturer’s data for pre-mix (bag) concrete if used for channel inverts and
benches
9. Manufacturer’s color chart for fiberglass vent pipe coatings
10. Manufacturer’s certification stating that FRP manholes conform to the requirements
of the contract documents and standards.
PART 2 -- PRODUCTS
2.01 FIBERGLASS MANHOLES AND BASE SECTIONS
A. Fiberglass
1. Provide prefabricated fiberglass manholes which conform in shape, size,
dimensions, and details shown on Drawings. Unless modified by Drawings, use
manhole sections conforming to ASTM D 3753.
2. Provide products manufactured by CSI, LFM, or equal. Mark date of manufacture
and name or trademark of manufacturer in 1-inch high stenciled letters on inside of
barrel.
3. Unless larger size is required, provide 48-inch diameter barrel for fiberglass
manholes. Provide wall section thickness for depth of manhole according to ASTM D
3753, but not less than .48 inches in thickness.
City of Denton Hazen and Sawyer
08/27/2018 Addendum No. 1 02083-3 Fiberglass Manholes
4. Provide fabricated reducer bonded at factory to form one continuous unit at top of
manhole barrel to accept concrete grade rings and cast iron frame and cover.
Reducer design shall be of sufficient strength to safely support HS-20 loading in
accordance with AASHTO
5. Provide manhole base of precast concrete conforming to Section 02082 – Precast
Concrete Manholes, unless cast-in-place base is indicated on Drawings.
6. Fiberglass manholes shall be designed for soil and surcharge loadings. Fiberglass
manholes subjected to vehicular traffic shall be designed for H-20 traffic loading.
Other fiberglass manholes shall be designed for a vertical live load of 300 psf.
Fiberglass manholes shall also be designed for groundwater at surface elevation
and the 100-year flood elevation.
B. Concrete
1. Conform to requirements of Section 03300, Cast-in-Place Concrete.
2. Channel Inverts: Use 5 sack premix (bag) concrete or Class A concrete for inverts
not integrally formed with manhole base, with minimum compressive strength of
4000 psi.
3. Concrete Foundation: Use Class A concrete with minimum compressive strength of
4000 psi for cast-in-place base and for foundation slab under manhole base section
where indicated on Drawings.
4. Cement Stabilized Sand Foundation: In lieu of foundation slab, provide cement
stabilized sand foundation under base section, when shown on manhole Drawings,
conforming to requirements of Section 02321 – Cement Stabilized Sand.
B. Reinforcing Steel
1. Provide reinforcing steel conforming to requirements of 03300, Cast-in-place
Concrete
C. Mortar
1. Conform to requirements of Section 04100, Mortar and Masonry Grout
D. Miscellaneous Metals
1. Provide cast-iron frames, rings, and covers conforming to requirements of Section
02090, Frames, Grates, Rings, and Covers
E. Drop Connection and Stubs
1. Provide drop connections and stubs conforming to same pipe material requirement
used in main pipe, unless otherwise indicated on Drawings.
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F. Pipe Connection for Sanitary Sewers
1. Stubouts and Connections: All FRP inserts and FRP sleeves for piping shall be
made as shown on installation drawings and in accordance with the manufacturer’s
FRP specifications for installation. Other methods of connections may be
performed per Engineers request or as shown in the plans and specifications, i.e.,
Inserta-Tee fittings, pipe connectors which conform to ASTM C-923 or PVC sewer
pipe with FRP lay-up reinforcement installed per manufacturer’s recommendation.
a. Inserta-Tee Fittings: Joints for Sewer Pipeline and drop connections, sizes
4”-15” shall be made by means of Inserta-Tee watertight compression
connection. Installation shall be in strict accordance with manufacturer’s
written instructions utilizing installation equipment approved for use by the
manufacturer of the Inserta-Tee fitting. Use of equipment which does not
meet this requirement is expressly prohibited. Inserta-Tee Fitting a product of
Inserta Fitting Co., Hillsboro, OR
b. Pipe Stubouts:
i. Install rubber gasketed PVC sewer pipe stubouts to manhole with
resin and glass-fiber reinforced lay-up. Gaskets shall meet the same
performance requirements of the sewer pipe to be installed unless
otherwise directed by Engineer. Resin and glass shall be of the same
type and grade as used in the fabrication of the FRP manhole.
ii. Install PVC or FRP pipe stubouts for use with resilient pipe-to-
manhole connectors (boots) which conform to the performance
requirements of ASTM C-923. PVC or FRP pipe stubouts may also
be used by placing incoming service piping through stubout and
sealing the annular space with expandable sealing mechanism, such
as “Inter-Lynx”. Inter-Lynx is a product of Advanced Products and
Systems, Inc., Lafayette, LA.
2. For drop, provide manufactured connection, such as Insert-a-Tee or equal, which
provides positive seal between pipe and wall.
G. Sealant Materials
1. Sealing material between adjustment ring and manhole, between each adjustment
ring, and between adjustment ring and manhole cover frame shall be a hydrophilic
elastic sealant, which adheres to concrete, fiberglass and metal, or approved
substitute.
2. Butyl Sealant: Provide Press-Seal EZ Stick, or equal, for HDPE rings.
H. Backfill Materials
1. Provide backfill in accordance with Section 02200, Earthwork
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08/27/2018 Addendum No. 1 02083-5 Fiberglass Manholes
I. Non-Shrink Grout
1. Provide prepackaged, inorganic, flowable, non-gas-liberating, nonmetallic, cement-
based grout requiring only addition of water.
2. Grout shall meet requirements of ASTM C 1107 and shall have minimum 28-day
compressive strength of 7000 psi.
J. Vent Pipes
1. Provide external vent pipes for manholes, where indicated on Drawings.
2. Buried Vent Pipes: provide 3-inch or 4-inch PVC DWB pipe conforming to ASTM D
2655. Alternately, provide FRP pipe as specified for vent outlet assembly.
3. Vent Outlet Assembly: Provide vent outlet assembly as show on Drawings,
constructed of following specified materials:
a. Fiberglass reinforced pipe conforming to ASTM D 2997. Seal cut ends in
accordance with manufacture’s recommendations
b. Provide epoxy bodied fittings and join pipe to fittings with epoxy adhesive,
according to pipe manufacturer’s instructions
c. Provide socket-flange fittings for epoxy adhesive bonding to pipe ends where
shown on Drawings. Flanges shall meet bolt patter dimension for ANSI B
16.1, 125-pound flanges. Flange bolts shall be hot-dip since coated,
conforming to ASTM A 307, Class A or B
d. Provide 2-component, aliphatic polyurethane coating using primer or tie coat
recommended by manufacturer. Provide two or more coats to yield dry film
thickness of at least 3 mils. Provide Amershield, Tnemec 74, or equal. Color
shall be selected by Project Manager from manufacturer’s standard colors.
PART 3 -- EXECUTION
3.01 EXAMINATION
A. Verify that lines and grades are correct.
B. Determine if subgrade, when scarified and recompacted, can be compacted to 95
percent of maximum Standard Proctor Density at +- 3% moisture content, according to
ASTM D 698 prior to placement of foundation material and base section. If it does not
meet the moisture- density requirement, condition the subgrade or treat as an unstable
subgrade.
C. Do not build manholes in ditches, swales, or drainage paths unless approved by
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08/27/2018 Addendum No. 1 02083-6 Fiberglass Manholes
Project Manager.
3.02 PLACEMENT
A. Install fiberglass manholes to conform to locations and dimensions shown on
Drawings. Do not install underneath existing or proposed pavement.
B. Place sanitary sewer manholes at points of change of alignment, grade,
size, pipe intersections, and end of sewer.
3.03 MANHOLE BASE SECTIONS AND FOUNDATIONS
A. Place base section and foundation as shown in the Drawings
3.04 CAST-IN-PLACE FOUNDATION
A. Where Drawings indicate cast-in-place manhole base, place concrete as shown on
Drawings on 4-inch (minimum) layer of either crushed stone, cement stabilized sand,
or seal slab. When unstable subgrade is identified, over-excavate subgrade to allow
for placement of 12- inch thick layer of crushed stone wrapped in filter fabric.
3.05 MANHOLE BARREL
A. Lower manhole barrel onto base section. Seal with manufacturer's gasket or
approved sealant. Wrap joint with external sealing material, minimum 12-inch
width.
B. Where cast-in-place base is used, support manhole barrel in place and brace it from
sides of excavation to prevent any movement of barrel during concrete placement and
while concrete is setting. Provide minimum clearance between reinforcing steel and
manhole barrel bottom as shown on Drawings. Do not support manhole barrel on
reinforcing steel. Place bead of water swelling sealant around inside of barrel near
bottom, as shown on Drawings, to form seal.
3.06 PIPE CONNECTIONS AT PRECAST MANHOLE BASE
A. Install approved resilient connectors at each pipe entering and exiting sanitary
sewer manholes in accordance with manufacturer's instructions.
B. Ensure that no concrete, cement stabilized sand, fill, or other solid material is allowed
to enter space between pipe and edge of wall opening at and around resilient
connector on either interior or exterior of manhole. When necessary, fill space with
compressible material to ensure full flexibility provided by resilient connector.
C. Test connection for watertight seal before backfilling.
3.07 PIPE CONNECTIONS AT CAST-IN PLACE BASE
A. Cut manhole barrel for pipe penetrations following curvature of pipe and with
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maximum of 1-inch clearance. Seal cut edges with resin. Hole may be circular or
cutout with semi- circular top which extends to bottom of barrel.
B. Place continuous bead of water swelling sealant, as shown on Drawings, around pipe
penetrations on interior of manhole barrel. Roughen surface of fiberglass prior to
placement to improve bond with sealant. Allow sealant to completely cure before
placing concrete against it.
C. Extend pipe entering manhole at least 8 inches into manhole. Fit pipes with neoprene
water- stop gasket seal placed tightly around pipe using stainless steel clamp.
Alternately, pipes may have continuous bead of water swelling sealant, as detailed on
Drawings, placed around pipe circumference.
D. When forming invert surface in bottom of manhole, mound concrete around
pipe penetrations so that water swelling sealant beads and neoprene water-
stop gasket have minimum 2 inches of concrete cover.
E. Test connection for watertight seal before backfilling.
3.08 INVERTS FOR SANITARY SEWERS
A. Construct invert channels as shown in the Drawings
3.09 DROP CONNECTIONS FOR SANITARY SEWERS
A. Backfill drop assembly with crushed stone wrapped in filter fabric, cement stabilized
sand, or Class A concrete to form solid mass. Extend cement stabilized sand or
concrete outside of bells minimum 4 inches.
B. Install drop connection when sewer line enters manhole higher than 24 inches above
invert of manhole.
C. At drop pipe connections through fiberglass barrel, cut circular hole sized to
requirements of manufactured connector. Seal cut edge with resin. Install watertight
connector according to manufacturer's recommendations.
3.10 STUBS FOR FUTURE CONNECTIONS
A. Where future connections are indicated on Drawings, install resilient connectors
and pipe stubs with approved watertight plugs in manholes.
B. At cast-in-place base, where future connections are indicated on Drawings, install
section of pipe extending no further than 12 inches from edge of foundation, ending
in bell and provided with rubber-gasket watertight plug.
3.11 ADJUSTMENT RINGS AND FRAME
A. Combine precast concrete or HDPE adjustment rings so that elevation of installed
casting cover matches pavement surface. Do not load manhole except on load
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bearing shoulder of manhole. Seal between adjustment ring and fiberglass
manhole with approved sealant material. Apply a latex bonding agent to precast
concrete surface and join with non-shrink grout. Set cast iron frame on adjustment
ring in bed of approved sealant material. Install sealant bed consisting of two
beads on sealant, each bead having minimum dimensions of 1/2-inch and 1/2-
inch wide.
B. Wrap manhole frame and adjustment rings with external sealing material, minimum
3 inches beyond joint between ring and frame and ring and precast section.
C. Set cast iron frame on top of cone or adjustment rings using water swelling sealant
materials and adjust elevation of casting cover to match pavement surface. For
manholes in unpaved areas, set top frame minimum of 6 inches above existing
ground line unless otherwise indicated on Drawings.
3.12 BACKFILL
A. After leakage testing, place and compact backfill material in area of excavation
surrounding manholes in accordance with requirements of Section 02200,
Earthwork. Use embedment zone backfill material, as specified for adjacent utilities,
from manhole foundation up to elevation 12-inches over each pipe connected to
manhole. Provide trench zone backfill, as specified for adjacent utilities, above
embedment zone backfill.
B. In unpaved areas, provide positive drainage away from manhole frame to natural
grade. Provide minimum of 4-inches of topsoil conforming to requirements of
Section 02500, Surface Restoration
3.13 FIELD QUALITY CONTROL
A. Conduct leakage testing of sanitary sewer manholes in Section 01470,
Watertightness Testing of Liquid Containing Structures.
3.14 PROTECTION
A. Protect manholes from damage until work has been finally accepted. Repair
damage to manholes at no additional cost to City.
- END OF SECTION
NOTES:3.CONNECTION BETWEEN FRP MANHOLE AND CAST-IN-PLACE CONCRETE BASE SHALL BEWATERTIGHT. DETAILS SHALL BE SUBMITTED INCLUDING THE REQUIRED EMBEDMENTAND MEANS OF CONCRETE ANCHORAGE. A MANUFACTURER'S CERTIFICATION LETTERSHALL ALSO BE SUBMITTED STATING THAT THE CONNECTION DESIGN CONFORMS TO THEREQUIREMENTS OF THE CONTRACT DOCUMENTS AND STANDARDS.#6@8"T&B, EW12"20"COMPACT SUBGRADEPER SPECS, TYP6" STONEFLEXIBLE BASE6" CONC MUDSLAB#6 RING BART&BMONOLITHIC CIPCONC BASEFRP MANHOLE, SEEDET 1/C-D-03 ANDSPECIFICATION 02083DETAIL9NTSCIP BASE SLAB FOR FRP MANHOLEC-D-03FRP MANHOLE TOCONC CONNECTION,SEE NOTE 36'-0" & 7'-0"DATEBYATTACHMENT NO.CONTRACTNUMBERADDENDUM NO.HAZEN JOBNUMBERDRAWING NUMBERREFER TO CONTRACTSHEETOF60702-0015768HICKORY CREEK DETENTION FACILITYAND PECAN CREEK WRPWEST PEAK FLOW PUMP STATIONCITY OF DENTON, TXSaved by gjohnson Save date = 8/23/2019 4:47 PMFile = O:\60702-DAL\60702-001\Drawings\STRU\S-HC-0108-27-1911S-HC-0111FPPHAZEN AND SAWYER8150 N. CENTRAL EXPRESSWAY, SUITE 700DALLAS, TX 75206TBPE FIRM REGISTRATION NO.F-13618LICNESED109383FREDRICK P. POWELL