GRAVITY SEWER REHABILITATIONCSEAO CONFERENCE, JUNE 5TH, 2017
V. Firat Sever, PhD, PE, BCEE
Goals of Sewer Rehab • Reduce/Eliminate Inflow
and Infiltration – Prevent Sanitary Sewer
Overflows (SSOs).– Reduce treatment plant flows
and operation costs.• Maintain structural integrity
of sewer system– Avoid catastrophic failures.– Prevent sewage backups
• Achieve regulatory compliance– EPA’s CMOM– Consent decrees
• Improve asset management
Funding Gap
Federal funding for wastewater infrastructure
CMOM
• Inspection coordination• Condition Assessment• Modeling• Defect/Impact Analysis• Decision Support Tools• Comprehensive assessment reports• Design• Maps/drawings (GIS or CAD)• Technical specifications
REGULATORY COMPLIANCECOST SAVINGS
Asset Management Condition
assessment/rehabilitation plan
WERF’s 10-step approach for water/wastewater facility asset management
Asset Management (contd.)
Adding Value to Sanitary Sewers
Rehab Decision Process Flow EVALUATE THE HYDRAULICS OF THE SYSTEM USING FIELD DATA/OBSERVATIONS AND
HYDRAULIC MODELING
INSPECT EACH PIPE SEGMENT WITH CCTV/SSET
ASSIGN A SCORE TO EACH DEFECT AND CALCULATE THE TOTAL CONDITION
SCORE
REVIEW INSPECTION REPORT AND CCTV VIDEO
IDENTIFY DEFECTS
IS UPSIZING NEEDED?
EVALUATE REPLACEMENT METHODS IS PIPE BURSTING
FEASIBLE/ECONOMICAL?
REPLACE TRENCHLESS BY BURSTING
RETRIEVE AND DOCUMENT INSPECTION
RECORDS
ASSIGN A COLOR CODE TO THE PIPE SEGMENT BASED ON CONDITION
IS RELINING (CIPP) FEASIBLE?
EVALUATE REPLACEMENT METHODS IS PIPE BURSTING
FEASIBLE/ECONOMICAL?
REPLACE TRENCHLESS BY BURSTING
REPLACE OPEN-CUT RELINE THE PIPE SEGMENT (EXAMPLE CIPP) REVIEW THE INSPECTION
RECORDS OVER
IS STRUCTURAL REHABILITATION
NECESSARY?
RELINE THE PIPE SEGMENT (EXAMPLE CIPP)
LIST THE DEFECTS AND DETERMINE DYSFUNCTIONS AND IMPACTS FOR EACH DEFECT
IS REHABILITATION NECESSARY?
LEAVE AS IS
IDENTIFY AVAILABLE TRENCHLESS POINT REPAIR
METHODS?
ASSIGN A METHOD (EXAMPLE CHEMICAL GROUTING, SEGMENTAL LINING) TO EACH DEFECT
LEAVE AS IS GREEN
RED
YELLOW
Evaluate hydraulic capacity
Identify defects and evaluate structural integrity
Economics and feasibility
YELLOW
RED
GREEN
LEAVE AS IS
OPEN-CUT POINT REPAIR
REHAB 100% TRENCHLESS (PREFERABLE)
CAN ALL THE DEFECTS BE REPAIRED BY TRENCHLESS TECHNOLOGIES?
ASSIGN A METHOD (EXAMPLE CHEMICAL GROUTING, SEGMENTAL LINING) TO EACH DEFECT
IDENTIFY AVAILABLE TRENCHLESS POINT REPAIR METHODS?
LEAVE AS IS
IS REHABILITATION NECESSARY?
LIST THE DEFECTS AND DETERMINE DYSFUNCTIONS AND IMPACTS FOR EACH DEFECT
RELINE THE PIPE SEGMENT (EXAMPLE CIPP)
IS STRUCTURAL REHABILITATION NECESSARY?
REVIEW THE INSPECTION RECORDS OVER
RELINE THE PIPE SEGMENT (EXAMPLE CIPP)
REPLACE OPEN-CUT
REPLACE TRENCHLESS BY BURSTING
IS PIPE BURSTING FEASIBLE/ECONOMICAL?
EVALUATE REPLACEMENT METHODS
IS RELINING (CIPP) FEASIBLE?
ASSIGN A COLOR CODE TO THE PIPE SEGMENT BASED ON CONDITION
RETRIEVE AND DOCUMENT INSPECTION RECORDS
REPLACE TRENCHLESS BY BURSTING
IS PIPE BURSTING FEASIBLE/ECONOMICAL?
EVALUATE REPLACEMENT METHODS
IS UPSIZING NEEDED?
IDENTIFY DEFECTS
REVIEW INSPECTION REPORT AND CCTV VIDEO
ASSIGN A SCORE TO EACH DEFECT AND CALCULATE THE TOTAL CONDITION SCORE
INSPECT EACH PIPE SEGMENT WITH CCTV/SSET
EVALUATE THE HYDRAULICS OF THE SYSTEM USING FIELD DATA/OBSERVATIONS AND HYDRAULIC MODELING
Sanitary Sewer Inspection
Man-Entry
Columbus LDA – Manhole Inspection w/ Pipetech™
PACP
• Pipeline Assessment and Certification Program
• 13 structural defect groups. More than 100 defect codes
PACP contd. PACP Code: Hole Void Visible (HVV)
Infiltration - Gusher
Structural Defects - Cracks
Structural Defects - Fractures
Corrosion (SAP)
Hole
Partial Failure
Collapse
Ovalization/Buckling
Rehabilitation Defects – Blistered Liner
FOG Buildup
Tree Roots
LACP
• Similar to PACP• Elaborate location
identification• Fittings
MACP
Manhole Defects – Displaced Frame
Manhole Defects – Corrosion
Manhole Defects – Failed Repair
Collapse
Keep small defects from becoming BIG problems!
Mapping / GIS
Inspection Progress Map
Business Risk ExposureThe picture can't be displayed.
BUSINESS RISK EXPOSURE = PROBABILITY OF FAILURE X CONSEQUENCES OF FAILURE
PresenterPresentation NotesPut a Structurepoint criticality map in the background
Criticality (contd.)
Rehabilitation - CIPP
Sliplining (Deform/Reform)
Geopolymer
Rigid Sliplining (GRP)
FRP Lining
PVC Panels
Rehabilitation Design
• Liner type and thickness matter• Loads (soil, groundwater, traffic,
other surcharge)• Environmental effects • ASTM F1216
– Empirical, partially / fully deteriorated design
Brick Conduits
Non-Circular Pipes
• Does ASTM F1216 work?
Manhole Rehabilitation
Manhole Rehabilitation contd.
WERF Project on Manhole Rehabilitation
Decision
Support Tool
Manhole Rehabilitation Material Classification
Experiments FEM
Expert Workshop
Literature Search
Case Studies
Main Test Participants
Strain Gage Installation
Main Tests (Stress vs. Strain)(1,100)
(900)
(700)
(500)
(300)
(100)
100
(170)(150)(130)(110)(90)(70)(50)(30)(10)1030
CMT2 CMT-EPX
PU1 PU2
PU3 EPX4
UNL
Strain [(in/in)x 10^-6)]
Stre
ss (p
si)
Finite Element Model – Hydrostatic Pressure on Liner
Finite Element Model (FEM) cont.
• Complete crushing test simulation on bare and lined samples
• Full-scale manhole modeling• Full-scale manhole
simulation with thinner wall• Full-scale manhole
simulation with deteriorated substrate (i.e. lower modulus of elasticity due to material degradation)
• Simulation for hydrostatic pressure on liner
Decision Support Tool (DST)
Enter MH condition
Enter soil properties
Enter groundwater
properties
Enter loads
Enter location information
Acceptable Structural Class and Materials
Acceptable Methods
Acceptable Classes, Materials, and
Rehabilitation Methods
Prepare technical
specification
Groundwater present?
Select the option with the lowest
price
Yes
No
Decision Support Tool ends here!
Enter MH condition
Acceptable Structural Class and Materials
Enter soil properties
Enter loads
Acceptable Classes, Materials, and Rehabilitation Methods
No
Groundwater present?
Enter groundwater properties
Yes
Select the option with the lowest price
Prepare technical specification
Enter location information
Acceptable Methods
DST – User Interface
User Interface created using Java Swing
Manhole Rehab Classification - Final
Manhole Rehabilitation
Materials
Structural (Class A) Semi-structural (Class B) Non-structural (Class C)
Polymer Concrete
Cured-in-place polymers (medium)
Cementitious lining (medium)
Fiberglass composite inserts
Cured-in-place polymers (thin)
Cementitious linings (thin)
Thermoplastic Sheets
Partial rehabilitation to stop I&I (e.g. chimney linings, grout sealants)
Cured-in-place (CIP) polymeric composites (steel reinforced)
Cured-in-place (CIP) polymeric composites
Cementitious lining (thick)
Cured-in-place polymers (thick)
Manhole Rehabilitation
Materials
Structural (Class A)
Semi-structural (Class B)
Non-structural (Class C)
Polymer
Concrete
Cured-in-place
polymers (medium)
Cementitious
lining (medium)
Fiberglass
composite
inserts
Cured-in-place
polymers (thin)
Cementitious
linings (thin)
Thermoplastic
Sheets
Partial rehabilitation to
stop I&I (e.g. chimney
linings, grout sealants)
Cured-in-place (CIP)
polymeric composites
(steel reinforced)
(steel reinforced)
Cured-in-place (CIP)
polymeric composites
Cementitious
lining (thick)
Cured-in-place
polymers (thick)
(Manhole RehabilitationMaterialsStructural (Class A)Semi-structural (Class B)Non-structural (Class C)Polymer ConcreteCured-in-place polymers (medium)Cementitious lining (medium)Fiberglass composite insertsCured-in-place polymers (thin)Cementitious linings (thin)Thermoplastic SheetsPartial rehabilitation to stop I&I (e.g. chimney linings, grout sealants)Cured-in-place (CIP) polymeric composites (steel reinforced)(steel reinforced)Cured-in-place (CIP) polymeric compositesCementitious lining (thick)Cured-in-place polymers (thick))
Manhole Rehab Cost
Conclusions
• Rehabilitation saves money• It does not always have to be fully-
structural• Criticality: Do it at the right place and right
time• No silver bullet: Always explore options• Use the right solution: Rehab design may
be complicated
Contact
Dr. Firat Sever, PE, [email protected]
GRAVITY SEWER REHABILITATIONGoals of Sewer Rehab Funding GapCMOMAsset Management Asset Management (contd.) Adding Value to Sanitary Sewers Rehab Decision Process FlowSanitary Sewer InspectionMan-Entry Columbus LDA – Manhole Inspection w/ Pipetech™PACPPACP contd. Infiltration - Gusher Structural Defects - Cracks Structural Defects - FracturesCorrosion (SAP) Hole Partial Failure Collapse Ovalization/BucklingRehabilitation Defects – Blistered LinerFOG Buildup Tree Roots LACP MACP Manhole Defects – Displaced Frame Manhole Defects – Corrosion Manhole Defects – Failed Repair CollapseMapping / GISInspection Progress MapBusiness Risk ExposureCriticality (contd.)Rehabilitation - CIPPSliplining (Deform/Reform)GeopolymerRigid Sliplining (GRP)FRP LiningPVC PanelsRehabilitation DesignBrick ConduitsNon-Circular PipesManhole RehabilitationManhole Rehabilitation contd.WERF Project on Manhole RehabilitationMain Test ParticipantsStrain Gage Installation Main Tests (Stress vs. Strain)Finite Element Model – Hydrostatic Pressure on Liner�Finite Element Model (FEM) cont.Decision Support Tool (DST)DST – User InterfaceManhole Rehab �Classification - FinalManhole Rehab CostConclusionsContact