San Antonio, TX July 28, 2011

Transcription

1 Rehabilitation of a Deteriorated 60 RCP Wastewater Interceptor Using Competing Trenchless Technologies Bruce Cole, PE Corey Anderson, EIT TAWWA/WEAT Summer Seminar San Antonio, TX July 28, 2011 Wendy Martinez, PE Mark Wade, PE Dan Buonadonna, EIT

2 Project Overview Presentation Outline Inspection/Assessment Phase Design Phase Bidding Phase Discussions

3 Project Statement of Objective Provide a renewed Rowlett Cottonwood RCP Transfer Sewer using strategic inspection technologies to evaluate pipeline rehabilitation options and trenchless solutions to promote competition through an innovative design and competitive bidding process.

4 Rowlett-Cottonwood Transfer Sewer System Wilson Creek Wastewater Treatment Plant Allen Junction Control Structure 60 and 54 RCP (1984) 60 FRP (2004)

5 Inspection and Assessment Results 2008 Part A Condition Inspection Manhole Inspections Pipeline Lamping Limited CCTV Inspections Flow Monitoring Part A Assessment Condition Assessment Scoring and Risk Assessment Condition Rating and Criticality Part B Condition Inspection Additional CCTV Inspections 2,D and 3-D Laser Profile Sonar Imaging (siphon) H2S Monitoring Part B Assessment Remaining Service Life Feasible Alternatives Hydraulic Analysis Technologies Used MudMaster CCTV Initial Recommendations Additional Inspections Quantification of Corrosion Evaluation of Siphon Technologies Used RedZone Robotics Final Recommendations Full-Scale Rehabilitation Phased Implementation Trenchless Solutions

6 Structural Condition: Findings and Results Severe deterioration generally consistent throughout entire alignment Extensive pipe joint failure and active I/I H2S levels measured up to 300 ppm Condition Rating: 4.5 (5 = very poor using SCREAM model) 90% of the pipeline has a factor of safety less than 1 Predicted Remaining Service Life: The range of predicted service life: 4-10 years (30% < 7yrs) Wastewater Flow Conditions: Metric (mgd) 60 RCP 60 FRP Total Projected 2030 Peak Wet-Weather Flow (10-yr) Projected 2030 Peak Base X Capacity (gravity) 73.2* Capacity (threshold surcharge) 77.0* * Sliplined Condition

7 Total Thickness of Cl III, IV RCP - 8 Thickness of Sacrificial Lining 3 60 ID RCP Citi Critical lzone of Corrosion (3-5 )

8 Sonar and CCTV Inspection (RedZone) SEVERE CORROSION ABOVE 10:00 AND 2:00 POSITIONS

9 Recommendations Pipeline Rehabilitation/Replacement Phase I Improvements (construction completed) Phase II ( construction to be completed August 2011) Siphon Cleaning Capacity improvement Wastewater Master Plan Comprehensive short-term flow monitoring program Development of a system-wide hydraulic model Condition assessment of strategic interceptor sewer systems

10 Review of Renewal Alternatives Review of potential ti alternatives ti Conditions and parameters: Peak flow delivery Permanent, corrosion-resistant resistant solution Long-term H2S control Highly urbanized and Flow control and odor management during construction

11 Review of Renewal Alternatives (cont d) Conditions and parameters (cont d): Proven record of renewal alternatives Availability of experienced installers Structural Renewal Alignment (bends and deflections) Selection of final alternatives Final pre-design workshop and collaboration

12 Initial Screening of Alternatives FRP Slipline PVC Slipline HDPE Ribline (SPR PE) CIPP Cut-and-Cover (FRP) Jointed Panels Pipe Bursting Cementitious Structural Coating Deformed/reformed HDPE Thermoformed PVC Lining

13 Review Matrix of Alternatives Criteria Sliplining Sliplining CIPP Ribline Open-Cut PVC FRP HDPE FRP No Bypass Pumping Required No Additional Access Pts Required Availability of Qualified Installers Structural Integrity Proven Technology Navigation of Bends/Deflections

14 Final Alternatives Selected Criteria Sliplining Sliplining CIPP Ribline Open-Cut PVC FRP HDPE FRP No Bypass Pumping Required No Additional Access Pts Required Availability of Qualified Installers Structural Integrity Proven Technology Navigation of Bends/Deflections

15 Rehabilitation Technologies Option 1 FRP Sliplining Pros Longer Distance between Manholes Can Install with Flow in Pipe Can Push 3,000+ LF Downstream (FRP) Can Push 2,000+ LF Upstream (FRP) Fewer Access Manholes Required Cons Insertion Pits are Required More Potential for Odor Problems Limit of 1.5% to 2% Deflection to Negotiate Bends Slight Reduction in Capacity due to Smaller ID Grout is Required in Annular Space High ground water at insertion pits

16 Rehabilitation Technologies Option 2 Cured in Place Pipe (CIPP) Pros Increase in Capacity due to Matching Corroded ID Minimal Excavation Required Work thru Manholes Smaller Footprint for Odor Control Cons Requires By-Pass Pumping During Active Insertion and Curing Requires Higher Level of Sewer Cleaning Will Require Addition of New Access Manholes - Maximum Length of Insertion is Approximately 1,000 LF Field Wetting is Sensitive to Hot Ambient Temperatures Active I/I may require pre-rehab correction (grout, prelining)

17 Rehabilitation Technologies Option 3 RIBLINE TM /SPR PE Pros Can Install with Flow in Pipe Minimal i Excavation Required Work thru Manholes Smaller Footprint for Odor Control High ground water can be accommodated Cons Will Require Addition of New Access Manholes - Maximum Length of Winding is Approximately 800 LF Slight Reduction in Capacity due to Smaller ID Grout is Required in Annular Space

18 Phase I Design 60 and 54 RCP (1984) 60 FRP (2004) Alt No 4 Alt No 3 Alt No 2 Alt No 1 Project Total Footage Base Bid 10,610 Bid Alt #1 1,790 Bid Alt #2 2,120 Bid Alt #3 1,230 Bid Alt #4 1,510 Total 17,260 Base Bid Allen Junction Control Structure

19 Phase 1 Project Coordination Issues Traffic control Construction permits Work in rights-of-way Odor control and management Wet-weather controls (during construction) Site restoration Potential contractor pool Ground water control, if necessary

20 Temporary Odor Control Strategies t Reduce flow thru the pipe by diverting flow at Allen Control Structure Batch or continuously treat remaining flow in pipe with chemical. Control odor at excavations Negative Pressure using mechanical ventilation Vapor phase treatment with dry media scrubber

21 Phase 1 Bid Results Contractor Technology Bid $/lf $/ID Engineer s Estimate Slipline $7,825,000 $453 $8.40 SJ Louis Slipline+CIPP $4,428,000 $256 $4.70 Boyer Slipline $5,269,000 $305 $5.65 Huff & Mitchell Slipline + Ribline $5,717,000 $331 $6.10 Southwest Pipeline Ribline $5,812,000 $337 $6.25 WRS Infrastructure t Slipline + Ribline $7,580, $439 $8.10 BRH-Garver Slipline $7,923,000 $459 $8.50 Boring & Tunneling Co. Ribline $8,038,000 $466 $8.65 Spiniello Slipline + CIPP $8,130,000 $471 $8.70 RePipe Construction CIPP $8,581,000 $497 $9.20

22 Phase 1 Construction ti

23 Phase 2 Project Layout WM6

24 Slide 23 WM6 Good slide. Can you add approx. lengths of each color coded segment? Also, can we kill the 625 in the scale? Can you add a W to WTP? WM, 1/25/2010

25 Phase 2 Special Considerations Temporary Access Easements CIPP Installation at Siphon Approaches (crossing residential properties) Siphon Cleaning Odor Control During Construction

26

27 Siphon Cleaning

28 Phase 2 Bid Results Contractor Technology Bid $/lf $/ID Engineer s Estimate Slipline $8.92 million $559 $10.35 SJ Louis Slipline+CIPP $4.84 million $303 $5.60 Oscar Renda Slipline $5.04 million $316 $5.85 Boyer Slipline $6.89 million $431 $7.98 Southwest Pipeline SPR $6.99 million $438 $8.11

29 Phase 2 Construction Almost Complete! Construction began in August 2010 All slipline pipe (> 12,000 LF) installed by December 2010 Siphon cleaning to be completed summer 2011 Minimal bypass pumping required Detailed laser profiling useful in evaluating adequate grout placement

30 Mission i Accomplished Met the Overall Project Goals: Reduced construction impact to neighborhood; Increased life span of this critical asset; Reduced potential I/I and resulting treatment costs; Saved construction costs through competitive trenchless bidding.

31 Keys to Success The Value of Higher-Level Diagnostic Inspection: Identified viable and real pipe renewal options; Aided in calculation of grout volume as required; Established pipe measured ovalities to assess structural renewal requirements. The Value of Competing Technologies: Created a level playing field ; Permitted a unique mix-and-match approach; Additional effort to design for 3 technologies added to a construction cost savings of more than 40%.

32 Thank You! Bruce Cole, NTMWD (972) Wendy Martinez, CH2M HILL (972)