Accepted Value Engineering
Proposal for Rohnert Park, CA.
THE MANHOLE LINER EXPERTS
PREDL Systems and BOSSales worked with Ghilotti Construction, GHD Engineering, Jensen Precast, and the City
of Rohnert Park to submit a Value Engineering proposal
that exceeded the specified requirements of the original bid.
Jensen Precast, Sacramento, CA manufactured the lined
MH structures.
Background
A few years ago Rohnert Park started a plan to rebuild existing MHs that required rehabilitation. I&I was a costly issue because another jurisdiction was paid a per gallon fee
to process sewage at a regional wastewater treatment
plant. Flow meter results indicated spikes associated with
storm events and possibly other non-event ground water
infiltration issues. Concrete corrosion in MHs due to H 2S
gas was a chronic issue that needed to be addressed.
PREDL Systems’ Solution
The submitted solution addressed overall cost, I&I control,
and protection against concrete corrosion. Installation complexity was substantially reduced providing lower costs and
shorter timeline for the total project. The final submittal pro- tect the concrete structure from the known corrosive effects
posed an entire concrete MH structure fully lined with FRP of H2S (Hydrogen Sulfide) gas and MIC (Microbial Induced
Corrosion). Joints between sections will be sealed with bu(Base) and PP (Barrel, Cover and Collar) components.
tyl, cap strips and plastic extrusion welds.
PREDL’s proposal supports the 24” DR25 C900 PVC pipe
within a 48” instead of 60” MH structure. This reduced con- All PREDL Liner System products are mechanically bonded
struction costs without compromising access and structural to the concrete during the precasting process. The MH
Base Liner flow channels are manufactured with exact facintegrity. PREDL’s FRP Bells are fully integrated with the
tory precision to align with the required pipe size, inlet anone-piece molded custom built MH Base Liner. Compresgles and elevations. The smooth non-porous flow channels
sion gaskets provide a watertight seal between the Base
help eliminate H2S gas produced by turbulence.
Liner and pipe system. This design has been proven to
control I&I for over 25 years in the sanitary sewers of comparable utilities. The MH barrels will be lined with PP to pro-
Original Proposal
60” or 72” Diameter Precast Concrete
Sanitary Sewer Manhole
1.
SHOP WELD HDPE BOOT FLANGE TO HDPE LINER ON MANHOLE ID.
(TYP).
2. MIN. OF ONE 3” HDPE GRADE AND ADJUSTMENT RING. MAX. OF ONE 1/4”
HDPE GRADE RING.
3. SEAL BARREL SECTIONS IN PLASTIC BASKET, RAM-NEK APPROVED
ALTERNATIVE. TYPICAL JOINT USE (2) 1/4” X 2 1/2” RAM-NEK SEALS.
4. SHOP APPLY 1/4” THICK POLYMER CONCRETE OVER TOP OF CONCRETE
BENCH. TROWEL SMOOTH AND SLOPE TOWARDS U-SHAPED CHANNEL.
5. AFTER LOWER RING SECTION IS SET, CUT OUT TOP HALF OF PIPE
FLUSH WITH INSIDE FACE OF M.H. WALL AND CONSTRUCT SHELF AND U
-SHAPED CHANNEL. MAKE ELEVATION CHANGES GRADUALLY AND DIRECTIONAL CHANGES WITH SMOOTH CURVES. SLOP AND SIZAE OF
CHANNELS SHALL MATCH UPSTREAM AND DOWNSTREAM PIPES. MANHOLE CHANNELS SHALL MATCH THE SLOPE OF THE PIPE.
6. PROVIDE COUPLING (TYP) PER SPECIFICATIONS. WRAP COUPLING WITH
50 ML CORROSION TAPE.
7. CAST PVC INLET/OUTLET STUB-OUTS INTO PRE-CAST MANHOLE BASE,
OR BARREL SECTIONS (TYP.) FILL AND ANNULAR VOIDS WITH NONSHRINK GROUT.
8. OVERLAP HDPE LINER 6” MIN. (TYP.) FIELD WELD OVERLAPPED SECTIONS.
9. PRE-CAST MANHOLE BASE AND BARREL SECTIONS WITH INTEGRAL
HDPE LINER.
10. GLUE HDPE B OOT TO PVC STUB-OUT (TYP).
11. VERIFY INLET/OUTLET ELEVATIONS AND ORIENTATION BEFORE ORDER-
predlsystems.com
PREDL Systems
Value Engineering Proposal
48” PREDL Lined Precast MH Base
ING PRECAST PRODUCTS.
12. INSTALL EXTERNAL JOINT SEAL AT ALL BARREL CONNECTION SECTIONS.
13. PROVIDE DUAL SST STRAPS OVER HDPE BOOT TO SECURE BOOT (TYP).
14. CUT AND REMOVE ANY EXCESS PVC INSIDE MANHOLE WITHOUT DISTURBING HDPE BOOT FLANGE.
15. WELD HDPE LINER TO HDPE GRADE RING (TYP).
16. TRIM BOTTOM OF FIRST HDPE GRADE RING TO SIT FLUSH ON MH SLAB.
17. SPARK TEST PER SPEC. (TYP).
18. VACUUM TEST RING JOINTS PER SPEC. (TYP).
19. TAPE WRAP HDPE GRADE RING JOINTS WITH 50 ML CORROSION TAPE
(TYP).
20. APPLY SEALANT BETWEEN FRAME AND GRADE RING (TYP).
ALL TASKS WITH STRIKE THROUGH INDICATES WAYS IN WHICH
TIME AND COSTS WERE REDUCED WITH PREDL’S VALUE ENGINEERING PROPOSAL. THESE STEPS TYPICALLY DONE AT THE
JOB SITE ARE COMPLETED IN ADVANCE WITH FACTORY PRECISION DURING THE FRP BASE LINER MANUFACTURING PROCESS. ADDITIONAL COST SAVINGS WERE REALIZED WHEN THE
REQUIRED SIZE OF THE MH WAS REDUCED FROM A 60” TO A 48”
STRUCTURE AS RESULT OF USING PREDL’S PROTECTIVE POLYMER LINER PRODUCTS..
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