JA-4,_Sewer_Main_Inspection_Report.pdf

"REPORT TYPE"

"NAME OF FACILITY - LINE 1"

"NAME OF SITE - LINE 2"

"City, State (do not abbreviate)"

VIDEO INSPECTION OF SEWER MAIN

FINAL REPORT

Eielson AFB, AK

September 2013

Prepared for:

354th CONS/LGCA

2310 Central Avenue, Room 304 Eielson AFB, AK 99702

Prepared by:

USKH Inc.

2515 A Street

Anchorage, Alaska 99503 Phone (907) 276-4245

Fax (907) 258-4653

USKH WO# 1233206

REPAIR SEWERLINE ON FLIGHTLINE AVE PH 1

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EIELSON AFB,ALASKA

PROJECT• NO.:FTQW 07-1116

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SUMMARY

The Eielson Air Force Base (EAFB) sewage wastewater is ultimately collected by a 12,650-foot-long sewer trunk main running generally parallel to Flightline Avenue from the wastewater treatment plant to the end of Flightline Avenue. This 18 and 24-inch concrete pipe was constructed in the 1950’s and presently carries on the order of 0.8 million gallons of wastewater per day. The peak flow is about 600 gallons per minute.

The Flightline Avenue sewer main is critical utility infrastructure; a failure in this buried pipe will disrupt wastewater collection to most if not all of EAFB until the pipe is repaired. In addition to the sanitary issues associated with loss of wastewater service, a break in this sewer main presents regulatory issues with unpermitted release of untreated sewage, and accompanying health risks to the installation. Portions of the pipe pass under airfield access roads and arterial traffic roads. If the pipe was to collapse, parts of the roadway could fail and be rendered impassable. This is an important sewer main that needs to be maintained in serviceable condition.

Due to age and the harsh climate, the pipe has deteriorated, and there is considerable concern about the condition and reliability of the sewer main. To assess the condition of the pipe, the 354th Civil Engineering Squadron (CES) contracted for the cleaning and video inspection of the pipe. The inspection found the following defects in the pipe:

• 7200 feet of heavily corroded pipe, with structural defects including:

o 85 feet of pipe with multiple fractures o 400 feet of pipe with multiple and longitudinal cracking o 7 holes in the pipe wall

• 34 manholes with rehabilitation required

• Infiltration and inflow I/I throughout the system

Repairs and rehabilitation of the existing sewer main is required at this time to address potential for pipe failure, to correct leaks and sanitary hazards, and to extend the useable life of the sewer main. A number of options for rehabilitation were examined; for initial purposes, it appears that installation of a cured-in-place (CIPP) pipe liner consisting of a reinforced fiberglass resin composite is the most viable and cost effective method. This will correct structural problems and leave the pipe in situ, with a minimum amount of excavation. A number of manholes and other items require additional repairs.

Of the 12,650-foot length of the sewer main, 7,200 feet need to be lined. The total construction cost for the rehabilitation project is estimated at approximately $2,933,069 including estimating contingencies.

Complete details of the condition assessment, recommendations, and a possible phasing plan for the rehabilitation work are provided in the report.

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TABLE OF CONTENTS

SUMMARY ................................................................................................................................................................... I

TABLE OF CONTENTS .................................................................................................................................................. II

TABLES AND FIGURES ................................................................................................................................................ III Figures .......................................................................................................................................................... iii Tables............................................................................................................................................................ iii

APPENDICES ............................................................................................................................................................... III

ACRONYMS ............................................................................................................................................................... IV

1 INTRODUCTION AND PROJECT OVERVIEW ................................................................................................... 1-1

1.1 PROJECT OVERVIEW ..................................................................................................................................... 1-1

1.2 REPORT PURPOSE ......................................................................................................................................... 1-1

1.3 FACILITY BACKGROUND ................................................................................................................................ 1-2

1.4 INVESTIGATIONS ........................................................................................................................................... 1-3

1.5 RECORD DOCUMENTS .................................................................................................................................. 1-3

1.6 APPLICABLE REGULATIONS AND DESIGN STANDARDS ................................................................................. 1-4

2 SEWER CONDITION ASSESSMENT................................................................................................................. 2-1

2.1 NASSCO/ PACP AND MACP CONDITION GRADING SYSTEM ......................................................................... 2-1

2.2 SEWER MAIN ASSESSMENT .......................................................................................................................... 2-1

2.2.1 MH 702 to MH 145 - 18-inch unreinforced concrete pipe ................................................................. 2-2

2.2.2 MH 145 to MH 9 – 24-inch Unreinforced Concrete Pipe .................................................................... 2-4

2.2.3 MH 9 to MH 0-2 – 24-inch unreinforced concrete pipe with CIPP liner installed .............................. 2-7

2.3 SEWER MANHOLE ASSESSMENT ................................................................................................................ 2-11

3 REHABILITATION OPTIONS ........................................................................................................................... 3-1

3.1 CONVENTIONAL EXCAVATION ...................................................................................................................... 3-1

3.2 LINING ........................................................................................................................................................... 3-1

3.2.1 SLIP LINING .......................................................................................................................................... 3-1

3.2.2 DEFORMED PIPE .................................................................................................................................. 3-2

3.2.3 CURED IN PLACE LINER ....................................................................................................................... 3-3

3.3 OTHER CONSIDERATIONS ............................................................................................................................. 3-3

3.3.1 OFFSET JOINTS .................................................................................................................................... 3-3

3.3.2 PROTRUDING/ERODED LATERALS ...................................................................................................... 3-4

3.4 MANHOLE REHABILITATION ......................................................................................................................... 3-4

3.4.1 Sprayed on Coating ............................................................................................................................. 3-4

3.4.2 Cured in Place Lining ........................................................................................................................... 3-4

3.4.3 Fiber Glass Insert ................................................................................................................................. 3-5

4 OTHER RECOMMENDATIONS ....................................................................................................................... 4-1

4.1 RV DUMP STATION ....................................................................................................................................... 4-1

4.2 SEPTIC SEWAGE FROM LIFT STATIONS ......................................................................................................... 4-1

5 RECOMMENDED IMPLEMENTATION, PROJECT PHASING AND COSTS ......................................................... 5-1

5.1 PHASE I .......................................................................................................................................................... 5-1

5.2 PHASE II ......................................................................................................................................................... 5-2

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5.3 PHASE III ........................................................................................................................................................ 5-2

5.4 PHASE IV ....................................................................................................................................................... 5-2

5.5 CONSTRUCTION COST ESTIMATES ................................................................................................................ 5-3

TABLES AND FIGURES

Figures Figure 1 – Vicinity and Location Map ..................................................................................................................... 1-2

Tables Table 1 – Pipeline Table ........................................................................................................................................ 2-14 Table 2 – Manhole Table ...................................................................................................................................... 2-19 Table 3 – Order of Magnitude Cost Estimate ......................................................................................................... 5-3

APPENDICES

Appendix A – Sewer Plan Sheets from Eielson Geobase Appendix B – Meeting Minutes Appendix C – PACP Legend and PACP Sewer Report Data Sheets Appendix D – PACP Pipe Run Graphs Appendix E – MACP Legend and Sewer Report Data Sheets Appendix F – USKH Manhole Inspection Reports Appendix G – DVD containing Still Photographs, Sewer Main CCTV, and Manhole CCTV

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ACRONYMS

AFB .......................... Air Force Base CES .......................... Civil Engineering Squadron CIPP ......................... Cured in place pipe CCTV........................ closed circuit television EAFB ........................ Eielson Air Force Base FL…………………………..Fracture Longitudinal FM ........................... Fracture Multiple FS ............................ Fracture Spiral I/I ............................ inflow and infiltration GPS .......................... Global Positioning System HDPE ....................... High Density Polyethylene MACP ...................... Manhole Assessment Certification Program MH .......................... manhole NASSCO ................... National Association of Sewer Service Companies PACP ....................... Pipeline Assessment and Certification Program PS ............................ Pipe Segment SAP .......................... Surface Aggregate Projecting SAV .......................... Surface Aggregate Visible UFC ......................... Uniform Facilities Criteria USKH ....................... USKH Inc.

WWTP…………………..Waste Water Treatment Plant

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1 INTRODUCTION AND PROJECT OVERVIEW

1.1 PROJECT OVERVIEW

Wastewater collection on Eielson Air Force Base (EAFB) is provided by a series of sewer mains, liftstations, manholes and related infrastructure distributed throughout the Base. The EAFB sewer mains discharge into a sewer trunk main running generally parallel to Flightline Avenue from the Waste Water Treatment Plant (WWTP) to the end of Flightline Avenue. This 18 and 24-inch concrete pipe was constructed in the 1950’s. The pipe presently carries on the order of 0.8 million gallons per day of wastewater, with peak flows to about 600 gallons per minute. Total capacity of the pipe is probably about twice this; present flows correspond to current personnel levels at EAFB.

As can be expected from the age (60 years plus), the pipe has deteriorated, and there is considerable concern about the condition and reliability of the sewer main. USKH Inc. (USKH) has been retained by the 354th Civil Engineering Squadron (CES) to investigate the condition of 12,600 feet of the Flightline Avenue sewer main and manholes from Dirt Boyz Street to the WWTP. The location of the pipe is shown on Figure 1, and on Drawings M1-M5 in Appendix A.

The Flightline Avenue sewer main is critical utility infrastructure; a failure in this buried pipe will disrupt wastewater collection to most if not all of EAFB until the pipe is repaired. In addition to the sanitary issues associated with loss of wastewater service, a break in this sewer main presents regulatory issues with unpermitted release of untreated sewage, and accompanying health risks to the installation. Lastly, portions of the pipe pass under airfield access roads and arterial traffic roads. The pipe is sufficiently large that if it was to collapse the roadway could fail and be rendered impassable for a period of time. This is an important sewer main that needs to be maintained in serviceable condition.

Based upon the findings and USKH’s recommendations, EAFB intends to program appropriate repair and rehabilitation projects to improve the reliability and extend the life of the sewer main.

1.2 REPORT PURPOSE

This report documents findings resulting from the field work accomplished, establishes various options available for repair of the defects, and makes recommendations for repairs. It includes prioritization, and estimates of probable construction cost. The report was developed based on several information sources, as follows:

• Prior Inspection report from Eielson Air Force Base titled 24” Sanitary Sewer Main Clean And Television Inspection, June 1998, Alaska Road Boring Inc.

• Pre-investigation meetings with USKH team and critical EAFB Staff.

• Closed circuit video (CCTV) inspection of the sewer main and manholes.

• Visual inspection of each accessible manhole.

• Manhole survey with GPS location.

• Various review meetings and site investigations.

1.3 FACILITY BACKGROUND

Eielson Air Force Base (AFB) dates to the early 1940s and World War II. In the late 1940’s and into 1950’s, Eielson AFB grew in size during the early days of the cold war. This included major utility projects, such as the WWTP, and the sewer collection system for the base. The Flightline Avenue sewer main was constructed in the 1950’s from ordinary concrete pipe. This 24 inch and 18 inch sewer truck main extends from the WWTP to Manhole (MH) 720. This nearly 3 mile long pipe carries all the wastewater for the base. The exact age is unknown, but this pipe is on the order of 60+ years in age. This is beyond normal life expectancy for concrete sewer mains, especially in arctic conditions, where freeze induced ground movement stresses the pipe. This can result in cracks and joint separations. The pipe is also subject to attack from corrosive gases released by the wastewater.

Figure 1 – Vicinity and Location Map

Record drawings for the original sewer main construction were not available during the development of this report.

In June of 1998, Alaska Road Boring inspected approximately 5000 feet of the sewer main, from the WWTP to approximately MH 9. Alaska Road Boring found considerable deterioration of the pipe, especially erosion of the joints, and exposed concrete aggregate, some of which was eroded deep enough to fall into the pipe. Cracks were also found, and it was deduced that the pipe was leaking wastewater into the soil, and the structural integrity of the pipe was questionable, and collapse or related failure likely.

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In approximately 2000, this 5000 +\- length of pipe was lined with a cured-in-place (CIPP) liner consisting of fiberglass cloth and plastic resins to seal and reinforce the pipe. We conclude this was successful, as the pipe is still in service 13 years later, and as the investigations for this project found, the CIPP liner is intact. There are a variety of construction defects in the liner, such as wrinkles and bulges which are addressed in more detail in Section 2 of this report, but nothing to suggest the liner is deteriorating.

1.4 INVESTIGATIONS

Investigations for this project consisted of visual observation of the sewer main and manhole by direct and closed circuit television (CCTV). CCTV was performed by USKH’s Subcontractor Frawner Corporation, a subsidiary of Alaska Road Boring Inc., who performed the earlier 1998 inspection. Due to the magnitude of this project, and the substantial wastewater flows involved considerable planning was required.

Field work included:

• Pre Inspection / Planning Kickoff. In April of 2013, USKH and Frawner Corporation meet with EAFB staff to review project scope, to review site and sewer main access provisions, and to discuss plans for sewer bypass pumping, cleaning and CCTV camera work. EAFB access requirements were coordinated, and work was scheduled for May after snow melt was complete. Minutes of this meeting are provided in Appendix B.

• Pre-Mobilization Meeting. In May, USKH and Frawner Corporation again meet with EAFB staff to firm up inspection plans, and confirm schedules. Bypass plans, traffic control plans, road crossings and road closures, safety requirements, and other procedures were discussed. Minutes of this meeting are provided in Appendix B.

• Pipeline CCTV work. On May 20th, Frawner Corporation mobilized to EAFB and began stockpiling needed equipment and materials. Sewer line cleaning and inspection work began in earnest on May 23, 2013, and extended through June 13, 2013, a total of 21 days. During this period of time, USKH personnel were on site with Frawner to assist with logistics, government coordination, and to observe the CCTV work and found defects real time. The findings of the CCTV work are presented in Section 2, and the PACP reports are provided in Appendices C and D.

• Manhole CCTV work. During the last several days of the CCTV work, USKH and Frawner completed condition assessments on the manholes. These findings are also presented in Section 2, and the MACP reports are provided in Appendices E and F. Still photographs, sewer main CCTV, and Manhole CCTV DVD(s) are located in Appendix G.

1.5 RECORD DOCUMENTS

Record drawings for the original sewer main construction were not available during the development of this report. Existing and prior information and documents available for development of this project were quite limited, and included only:

• Department of the Air Force, Pacific Air Forces Comprehensive Plan, Sanitary Sewer System Plan, Eielson A.F.B., Alaska.

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• Statement of Work, Video Inspection of Sewer Main, Project Number FTQW07-1115, Project Location:

Eielson AFB, AK - 15 March 2012

• Prior Inspection report from Eielson Air Force Base titled 24” Sanitary Sewer Main Clean And Television Inspection, June 1998, Alaska Road Boring Inc.

Because of the limited record documents available, the majority of information presented within this report was collected by field investigations.

1.6 APPLICABLE REGULATIONS AND DESIGN STANDARDS

The project investigations, this report, and the recommendations presented herein were developed in accordance with the following standards and regulations:

• NASSCO - National Association of Sewer Service Companies

• Alaska Administrative Code, 18 AAC 70, Water Quality

• Alaska Administrative Code, 18 AAC 72, Wastewater Disposal

• Recommended Standards for Wastewater Facilities, Great Lakes – Upper Mississippi River Board of State and Public Health and Environmental Managers, more commonly known as the “10 State Standards”, 2004 Edition

• Uniform Facilities Criteria (UFC), Wastewater Collection and Pumping, UFC 3-240-06A

NASSCO is a recognized national association that has established standards for performing condition assessments of sewer mains and sewer manholes, and training / certification programs for individuals performing the condition assessments. NASSCO is discussed in more detail in Section 2.

The Alaska Administrative Code (AAC), administered by the Alaska Department of Environmental Conservation (ADEC) established minimum sanitary requirements and environmental health requirements for wastewater systems, including sewer mains and pumping stations. ADEC has primacy for enforcement of wastewater regulations in Alaska. In general the ADEC / AAC regulations require that recognized design best practices be adhered to. For Alaska, and for most of the United States, the typical reference for recommended operating practices is the 10 State Standards.

2 SEWER CONDITION ASSESSMENT

2.1 NASSCO/ PACP AND MACP CONDITION GRADING SYSTEM

National Association of Sewer Service Companies (NASSCO) was formed in 1976 with the goal of improving the success rate of the pipeline rehabilitation industry. NASSCO is an organization that has developed standardized rating system for use in the inspection of existing pipeline systems. Among the many certification programs they have developed are the Pipeline Assessment and Certification Program (PACP) and the Manhole Assessment Certification Program (MACP). These programs provide standard defect codes for use in the inspection of pipelines in an effort to provide an objective rating system. All CCTV assessment work and data reported in this report was collected by NASSCO certified staff and conforms to the MACP and PACP criteria.

2.2 SEWER MAIN ASSESSMENT

The sewer main assessment involved several steps. All the steps were necessary in order to get quality video of the entire sewer system within the defined project. In general, for each run of pipe between manholes the following steps were completed:

1. The video van was positioned at the upstream manhole and a reconnaissance pass with the closed circuit video (CCTV) was made through the pipe to check access and the condition of the pipe. In most cases a bypass was set up to divert the existing flow. In some cases where the flow was minimal the upstream line was plugged for a short time while the inspection was completed.

2. If there was adequate access and the pipe visually appeared sound enough to withstand cleaning without problems, a high pressure (1700- 2000 psi) sewer jetter unit was introduced from the downstream manhole and the line was cleaned, pulling debris from the upstream to the downstream manhole. In most segments of pipe, there were significant amounts of sand, gravel, and sludge so several passes with the jetter were required to clean the line. In some locations, there was occurrence of large debris, including items such as recreational vehicle (RV) sewage dump hoses, plywood, and solids removed over the course of the cleaning. At least one empty bucket was also removed from the pipe.

3. Once cleaning was complete the line was inspected and recorded using the CCTV camera. PACP coding was used to designate the various defects found throughout the pipe. Still pictures were recorded for many of the typical defects found.

The CCTV work began at the upstream end of the project at Manhole 702 adjacent to Dirt Boyz Street, and proceeded downstream to the WWTP.

In general, the mainline sewer inspected can logically be broken down into three distinct sections; the results of the inspection for each of the three sections are discussed in the following pages and include photographs of typical defects. The CCTV inspection findings are summarized in Table 1 which begins on page 2-14. Copies of the complete PACP reports and plotted defect locations are included in Appendices C and D.

2.2.1 MH 702 to MH 145 - 18-inch unreinforced concrete pipe

This section of the project is located along the south side of Flightline Avenue between Dirt Boyz Street and Division Street. Referring to Table 1, this section of the project encompasses pipe segments 1 - 6.

EAFB geobase maps report this pipe as 24 inch diameter, but it was found to be only 18 inch diameter during inspection. Flows were low to moderate in this segment of pipe.

Defects found in this section included surface and structural damage, as well as operation and maintenance defects such as compacted deposits of sand and gravel, protruding lateral connections, inflow and infiltration (I/I) and grout intruding into the pipe. Below are a series of photographs taken showing the typical defects found in this portion of the project. The length of 18-inch pipe surveyed is approximately 2059 feet.

Photo 1 was taken 134.4 feet in from MH34, this line was inspected from MH34 as Manhole 702 is really an enclosed utilidor and the pipe was not accessible. This picture shows an example of an area with multiple fractures (structural defect) in the pipe wall. There were several areas from 130 feet to 150 feet into this line where fracture defects were noted. While the pipe wall in this area was noted as Surface Aggregate Visible (SAV) and not excessively corroded, the multiple fractures, spiral fractures, and hole in the pipe, all suggest the pipe is in poor structural condition. This segment of pipe is located under Flightline Avenue, additional deterioration and eventual failure will cause sewer service disruption and potential access issues along Flightline Avenue.

Photo 2 shows a typical spiral fracture in this same area.

There were also longitudinal fractures and a hole noted in this area.

Photo 1 - Pipe Segment (PS) 1, MH34- MH 702 at 134.4 feet (FM) Fracture Multiple

Photo 2 - PS 1, MH34-Utilidor702 at 132.3 feet (FS) Fracture Spiral

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Photo 3 and 4 are typical pictures of holes found in the side wall of the concrete pipe. The survey technician noted the soil was visible beyond the pipe wall in photo 3; it may be more of a fracture with the pipe wall still partially intact with exposed aggregate. Photo 4 is of a joint where the mortar is missing as well as a portion of the pipe. In this segment the condition of the pipe wall was generally noted as SAV, but as you can see in several pictures the aggregate is visible and in some cases projecting as in Photo 4 of the eroding joint.

Photo’s 5 and 6 show two typical operation and maintenance type defects. Photo 5 is showing the tire of the video camera parked on top of settled gravel deposits which remained after the cleaning. About 20% to 30% of the pipe diameter in this segment was occluded with sand and sediment in the bottom of the pipe (before cleaning). These thick deposits create dams that accumulate additional material over time, increasing the likelihood of pipe blockage. These dams allow sewage to pond in the pipe which contributes to production of corrosive sewer gases. Percentages of deposits remaining after cleaning are noted in Table 1, Sewer Main Inspection Summary.

Photo 6 shows an intrusion of grout material at a joint in the invert of the pipe, it is difficult to see clearly but shows up well in the video footage.

Photo 5 - PS 5, MH21-MH20 at 236.8 feet (DSC) Deposits Settled Compacted

Photo 6 - PS 6, MH20-MH145 at 210.4 feet (ISGT) Intruding Sealing Grout

Photo 3 - PS 2, MH34-MH23 at 345.5 feet (HSV) Hole Soil Visible

Photo 4 - PS 5, MH21-MH20 at 223.5 feet (HVV) Hole Void Visible

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Within this 2059 foot long segment of pipe, gross defects noted included:

• 85 feet of pipeline with multiple, spiral, hinge, and longitudinal fractures;

• 1 area of longitudinal cracking;

• 3 holes in the pipe wall;

• 2059 feet of corroded pipeline noted as surface aggregate visible;

• 6 instances of protruding service line pipe and protruding grout at the joints; and

• Multiple areas of compacted gravel in the invert of the pipe and inflow/infiltration.

The above listed defects all indicate a pipeline near, or past, the end of its design life and in danger of unexpected failure. Problems could occur unexpectedly anywhere along this section of the project, but the immediate concern is with segments 1 and 5 as they have significant fractured sections that will eventually collapse. Section 3 of this report includes the various options commonly available for rehabilitation of pipelines in this condition with advantages and disadvantages associated with each method. Section 5 includes the phasing of the entire study area into 4 phases prioritized based on the severity of the defects found. Pipe segments 1 and 5 have been identified as the top priority and therefore, Phase 1.

2.2.2 MH 145 to MH 9 – 24-inch Unreinforced Concrete Pipe

This section of the project is located along the south side of Flightline Avenue between Division Street and Tanana Street. Refer to Table 1, pipe segments 7-22. This pipe is 24 inches in diameter as expected. Sewer flows in the main increased substantially downstream of Division Street where liftstation 507 begins contributing to the flow. The occurrence of heavy debris in the pipe, especially RV dump hoses increased after this lift station location.

Defects found in this section included surface and structural damage, as well as operation and maintenance defects such as compacted deposits of sand and gravel, protruding lateral connections, inflow and infiltration (I/I) and grout intruding into the pipe. Below are a series of photographs taken showing some of the typical defects found in this portion of the project. The length of this section of 24-inch concrete pipe is 5,099 feet.

Photo 7 shows debris taken out of MH 145, upstream Pipe Segment 6. Notable are the RV discharge hoses removed from the pipe, this is an operational problem with the system and is covered in more detail in Section 4.1 of this report.

Photo 7 - MH 145 Debris removed from

PS 6

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Photo 8 shows a lateral connecting to the 24-inch main through the side wall. The invert of the service tap, as well as the main line pipe wall has been eroded over time. The service is active but in need of repair or replacement. The PACP code for this type of defect is TBD for “Tap Break In Defective”.

Photo 9 shows a portion of a joint with mortar missing and soil showing beyond the pipe wall. Mortar missing or protruding was common throughout the un-lined portion of the project. This is also a good example of the defect code Surface Aggregate Visible (SAV) where the surface is still relatively smooth but concrete fines have been corroded away as a result of aggressive sewer gases. It is important to note that the upper portion of the project, the 18-inch main and the 24-inch main down to MH14, all were noted as SAV while the lower portion of the 24-inch un-lined main was consistently noted as Surface Aggregate Projecting (SAP). This pipe section is marked by a dramatic increase in the presence and severity of pipe corrosion damage, especially downstream of Broadway Street. At this location, additional lift stations begin contributing to the sewer flows, but the wastewater is “older” and becoming septic (a low oxygen condition) after prolonged residence time in the collection system. Septic sewage increases the generation of corrosive sewer gases, which condense on and attack the concrete pipe.

Photo10 is a good example of a lateral intruding into the main line. All of the lateral taps within the project varied somewhat but the majority were similar to this one with more or less lateral pipe exposed. Service taps intruding into the mainline are an operation and maintenance problem, at higher flows they can collect solids, impeding flow, they are a barrier to cleaning and inspection equipment, and they will need to be cut flush with the pipe wall prior to any method of pipe lining.

Photo 8 PS 7, MH145-MH19 at 124.1 feet (TBD) Lateral Connection Defect

Photo 9 - PS 9, MH18-MH17A at 12.2 feet (H) Hole

Photo 10 - PS 12, MH16-MH15 at 106.7 (TBI) Tap Break-in Intruding

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Photo’s 11, 12, and 13 show examples of I/I, the first appears to be a small hole located at a joint, the second a weeping joint evidenced by the staining, and finally a hole with bubbling flow into the sewer. Water staining at the joints was the most common defect noted relating to I/I, with 5 areas noted as infiltration gusher or runner.

Note that the sewer video inspection was performed after snow melt, and during a relatively dry spring period.

The I/I flows are likely higher during spring melt, and in the August / September fall rainy period.

Photo 11 - PS 10, MH17A-MH17 at 85.4 (IG) Infiltration Gusher

Photo 12 - PS 12, MH16-MH15 at 3.8 feet (IS) Infiltration Stain

Photo 13 - PS 18, MH12A-MH12 at 5.9 feet (H,IG) Hole, Infiltration Gusher

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Photo 14 shows a good example of mortar missing from a joint, Table 1 shows this as a common occurrence. The absence of mortar at the joints contributes to I/I and overall joint deterioration. In low groundwater conditions, sewage may be leaking out of the pipe into the surrounding soil. Finally, photo 14 shows an example of Surface Aggregate Projecting (SAP).

Within this 5099 foot long segment of pipe, gross defects noted included:

• 400 feet of pipeline with multiple and longitudinal cracking;

• 4 holes in the pipe wall;

• 2402 feet of pipeline noted as surface aggregate visible;

• 2696 feet of pipeline noted as surface aggregate projecting;

• 17 instances if protruding service line pipe or protruding grout at the joints;

• 4 areas of compacted gravel in the invert of the pipe; and

• Grout noted as missing and I/I throughout the pipe joints in this section of the project.

As with the upstream 18-inch portion of the study area, the above listed defects all indicate a pipeline near, or past, the end of its design life and in danger of unexpected failure. This portion of the project transits some of the most densely developed area on EAFB adding to the critical nature of the need for continuous operation. As noted above, there are significant defects in this section that will need to be addressed in the next 2-3 year time frame; rehabilitation of the highly corroded pipe in segments 16 through 22 has been prioritized as Phase II.

Section 5 details the work included in Phase II and III, which between these two phases encompasses the rehabilitation of the remaining un-lined sewer pipe, 18 and 24-inch, within this project.

2.2.3 MH 9 to MH 0-2 – 24-inch unreinforced concrete pipe with CIPP liner installed

This section of the project is located along the North side of Flightline Avenue between Tanana Street and Kijik Loop (WWTP). Referring to Table 1, this final section from MH 9 to the WWTP includes Segments 23-34.

Photo 14 - PS 18, MH12A-MH12 at 6.6 feet (SZ) Surface Other, Grout Missing from Joint

Photo 15 - PS 22, MH9A-MH9 at 0 feet (SAP) Surface Aggregate Projecting

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This section of the project had a CIPP liner installed in 2000, so the CCTV field observations, and many of the defects noted were associated with the liner. These are either defects occurring over time or defects associated with the original installation of the liner. Below are a series of photographs taken showing some of the typical defects found in this portion of the project. The length of this section of 24-inch previously lined concrete pipe is 5,423 feet.

Photo 16 shows blistering of the liner surface which likely occurred shortly after or during curing of the installed liner. This defect minimally adds to the roughness of the pipe surface but does not appear to impact the operation of the system.

Photo 17 shows a defect where the liner meets MH8. The picture is taken looking down at the channel of the MH where the liner begins. It appears there is a wrinkle or fin in the original liner; over time liner material or sealant has eroded away. There is one other location (MH 0-1) where the liner connection to the manhole is defective

Photo 18 appears to be a case of the liner deforming into a flat section, not so much a bulge but nevertheless a defect as the pipe is out of round. This defect may encourage settling out of sewer solids in this area under some flow conditions, but should not affect system performance significantly.

Photo 16 - PS 23, MH9-MH8 at 2 feet (LFB) Lining Failure

Photo 17 - PS 24, MH8-MH7 at 0.0 feet (LFDE) Liner Failure Defective End

Photo 18 - PS 25, MH7-MH6 at 2.3 feet (LFZ) Lining Failure Other

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Photo’s 19, 20, and 21 show a typical liner wrinkle, bulge and joint with joint tape peeling. The bulges tend to be along the invert parallel to the flow. Normal flow is mostly unimpeded. These are defects that likely occurred during the installation of the CIPP liner. The liner is pulled into place or inverted into place, then typically cured with hot water (Section 3 covers this in more detail). There are many factors such as I/I, selection of liner materials and size of liner to be used; pipe grade and alignment; condition of pipe surface, etc., that can influence liner installation. Wrinkles are often related to an oversized liner being used; because older concrete pipes vary in size, it is difficult to get a liner that fits exactly in all segments of the pipe. In this case these construction defects should have been corrected/ mitigated prior to acceptance by grinding of the protrusions followed by resin application. However, these defects are limited in length, and review of the video shows these areas are exception to the otherwise good liner installation..

Photo 21 shows where the factory seam tape is coming free from the liner joint, it did not appear that the operation of the system would be affected by this defect.

Photo 19 - PS 30, MH3-MH2 at 550 feet Photo 20 - PS 31, MH0-2-MH0-1 at 213 feet

Photo 21 - PS 31, MH2-MH1 at 556.4 feet (LFZ) Lining Failure Other (Factory Seam Failure

REPAIR SEWERLINE ON FLIGHTLINE AVE PH 1

(B9039)

Photo 22 shows a close up of a deposit of unknown material in the invert of the pipe. In relation to the overall pipe the deposit is small and does not dam the entire invert (see Video). The debris is strongly adhered to the pipe as repeated jetting did not remove the material. This is typical of 3 other defects noted as (OBZ).

Photo 23 shows where the pipe coming into MH 0-2 is lower than the manhole channel causing ponding in the pipe. Review of the video in this section is useful in understanding this photo. This is an O&M issue that should be investigated further when Phase IV is undertaken, it is not currently significant to operation of the system but ideally would be corrected along with other liner defects in Phase IV.

The defects found in this 5,423 foot section of previously CIPP lined pipe are as follows:

• 108 feet of bulged liner;

• 38 feet of wrinkled liner;

• 3 locations where unknown debris is adhered to the liner;

• 4 factory seam failures; and

• Discoloration of the liner throughout.

Generally, this portion of the system is in good operational condition with relatively minor defects; the liner project completed in 2000 was successful in extending the useful life of the 24-inch sewer main in this area. A 50-year design life is commonly referenced in product literature and technical specifications associated with CIPP liner projects. The majority of work associated with additional rehabilitation is where the existing liner meets the manholes and within the manholes themselves. This work is the lowest priority and may either be accomplished with another phase or left until last.

Photo 22- PS 31, MH2-MH1 at 556.4 feet (LFZ) Lining Failure Other (Factory Seam Failure

Photo 23- PS 33 MH0-1-MH0-2 at 0.0 feet (OBZ) Obstacle Other (Pipe invert offset at manhole

REPAIR SEWERLINE ON FLIGHTLINE AVE PH 1

(B9039)

2.3 SEWER MANHOLE ASSESSMENT

Sewer manholes (31) were individually assessed after the sewer main CCTV work was completed. Three manholes were located under pavement and inaccessible. Each manhole was recorded using a video camera mounted on a pole. Each individual MH inspection started the video recording at the cover of the MH and ended near the pipe invert. The camera was rotated through 360 degrees then lowered and the process repeated until full coverage was achieved. Additionally, each MH was visually inspected for condition and the physical dimensions recorded; several still pictures were taken for each manhole. The manholes were also located using GPS survey equipment accurate to 1 meter. Refer to Table 2 on page 2-19 for detailed information for each manhole surveyed. The MACP reports are provided in Appendix E, and USKH manhole inventory forms with attribute data are provided in Appendix F.

Throughout the project, the predominant manhole structure is a rectangular cast-in-place concrete structure with a flat slab concrete top. Access and grade adjustment is accomplished with an octagon shaped cast-in-place manhole chimney with an iron manhole lid and frame cast into the concrete (Photo 24). The interior of the typical MH is oriented with the long side parallel to the direction of flow; the pipe invert connects on the short side (Photo 25). There are a few other manhole configurations but this rectangular MH appeared to be the standard used during the original construction of the sewer system. The other configurations appeared to be newer additions or modifications required as the system aged or changes were made. Photo 26 shows the standard cover used for this system. The manholes throughout the study area appear to be well built, and are in relatively good condition for the age of the system.

Photo 24 provides a good example of the exterior of the standard manhole that was used throughout the system, as noted previously the MH’s are cast in place concrete, with a flat slab top and octagon riser. In this particular picture the concrete is in sound condition and the manhole operational.

Photo 25 is an interior picture of the standard manhole, with 24-inch inlet and outlet. It is an example of the MACP code Surface Aggregate Projecting (SAP) as it relates to the concrete condition of a manhole. All of the un-lined manholes in the study area had some level of concrete corrosion with five MH’s noted with the more severe defect SAP.

Photo 24 - MH 9A Typical Cast-in-Place Manhole

Photo 25 - MH 9A Interior View (24-inch Main)

REPAIR SEWERLINE ON FLIGHTLINE AVE PH 1

(B9039)

Photo 26 is an example of the typical frame and cover. Generally the frames and covers were in good condition with varied degrees of corrosion.

Photo 27 is another example of concrete corrosion near the invert of the main sewer where a service line extends into the system. Left unchecked, the manhole surface corrosion will continue adding sand and gravel to the sewer system and exposing increased surface area for corrosive sewer gasses to attack. The rehabilitation/ protection of the project manholes will increase in cost as the surface corrosion increases.

The concrete weathering shown in Photo 28 is typical of 4 MH risers. The repair for this defect is to demolish the existing riser and replace, including a new frame and cover. Photo 29 (next page) shows an example of a corroded iron frame that should be replaced at some point in the normal course of maintaining the overall system. The majority of the frames and covers inspected were in fair condition and have significant useful life remaining.

Photo 27 - MH 13 (SAP) Surface Aggregate Projecting

Photo 26 - MH 9A MH Cover (Typical)

Photo 28 - MH 15 Concrete Weathering

REPAIR SEWERLINE ON FLIGHTLINE AVE PH 1

(B9039)

Manholes previously lined in 2000 are showing signs of deteriorating condition, in many cases the liner that was applied is coming away from the walls of the manhole as depicted in Photo 30. This type of defect was noted in 9 of the previously lined manholes. This defect could cause operation problems if large sheets peel away from the concrete and end up as a blockage in the pipe, it also provides an unventilated area between the peeling liner and the concrete for aggressive sewer gases to accumulate.

The defects noted during the survey included interior concrete surface corrosion, exterior concrete weathering, corroded cast iron frame and covers, and liner failure in those manholes that were previously rehabilitated. The manholes throughout the system were generally in good operational condition, with the exception of the defects noted below:

• 14 noted with Surface Aggregate Visible;

• 5 noted with Surface Aggregate Projecting;

• Liner failure in 9 manholes;

• 4 weathered concrete risers; and

• Varied levels of corrosion of cast iron frames and lids.

Photo 29 - MH 9A “Pitted” Cast Iron Frame Photo 30 - MH 4 Manhole Liner Failure (Typical)

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(B9039)

(B9039)

TABLE 1: SEWER MAIN INSPECTION SUMMARY

Start (Ft) Finish (Ft) Fracture Hole Surface Damage Lining Failure Deposit Infiltration Obstacle Construction

0.0 136.5 (SAV) Aggregate Visible

0.0 8.3 (DSGV) Gravel 15%

130.8 -- (H) Hole

132.3 134.4 (FS, FL, FM)

Multiple Yes

148.8 -- (FM) Multiple Joint

184.3 197.5 (DSGV) Gravel 10%

247.8 252.3 (DSGV) Gravel 5%

0.0 130.0 (SRI) Roughness Increase

130.0 422.4 (SAVZ) Aggregate Visible

345.5 -- (HSV) Soil Visible

2.0 408.0 (SAV) Aggregate Visible

24.8 -- (TBI) Tap Break-In Intruding 8" Intrusion

49.1 -- (ISGT) Intruding Grout

0.0 187.7 (SAV) Aggregate Visible

158.4 168.1 (DSGV) Gravel

186.1 -- (TBI) Tap Break-In Intruding

10" Intrusion, Blocked Video Passage

0.0 216.4 (SAV) Aggregate Visible

0.0 -- (DSC) Compacted 5%

32.8 -- (IR) Runner

122.0 -- (DSC) Compacted 5%

161.8 174.1 (DSC) Compacted 5%

215.9 -- (TBI) Tap Break-In Intruding

10" Intrusion, Blocked Video Passage

0.0 239.1 (SAV) Aggregate Visible

73.5 -- (ISGT) Intruding Grout

128.0 193.4

(FL,FH4)

Longitudinal & Hinge

Yes

223.5 -- (HVV) Void Visible

236.8 -- (DSC) Compacted 10%

0.0 325.2 (SAV) Aggregate Visible

210.4 -- (ISGT) Intruding Grout

307.2 -- (CL) Crack Longitudinal

4 (Up) 22 21 18 216.4

5 21 20 18 239.1

Defect Rehabilitation Phasing PriorityNotes3Inter-mittent2 Defect Location1Upstream

Manhole Pipe

Segment Downstream

Manhole Diameter

(In) Surveyed

Length (Ft) 18 259.9

4 (Down) 22 21 18

145 18 325.26 20

187.7

3 23 22 18 408.0

2 34 23 18 422.4

1 702

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(B9039)

Start (Ft) Finish (Ft) Fracture Hole Surface Damage Lining Failure Deposit Infiltration Obstacle Construction Defect Rehabilitation

Phasing PriorityNotes3Inter-mittent2

Defect Location1Upstream Manhole

Pipe Segment

Downstream Manhole

Diameter (In)

Surveyed Length (Ft)

0.0 487.4 (SAV) Aggregate Visible Grout in Joints Missing

99.5 286.2 (CL, CM) Crack Multiple Yes

124.1 -- (TBD) Tap Break- In Defective

166.3 -- (IS) Intruding Sealing Material

0.0 67.6 (SAV) Aggregate Visible

226.0 -- (DSC) Compacted 5%

0.0 180.9 (SAV) Aggregate Visible

12.2 18.3 (H) Hole Yes Holes at Joints

18.3 33.1 (IS) Intruding Sealing Material Yes

0.0 178.6 (SAV) Aggregate Visible

0.0 -- (CL) Crack Longitudinal Joint

85.4 -- (IG) Gusher Joint

0.0 498.8 (SAV) Aggregate Visible

174.0 406.0 (IS) Intruding Sealing Material Yes

0.0 499.6 (SAV) Aggregate Visible

3.8 150.0 (IS) Intruding Sealing Material Yes

10.1 16.0 (DSGV) Gravel 5%

67.2 -- (TBI) Tap Break-In Intruding 5" Intrusion

106.7 -- (TBI) Tap Break-In Intruding 4" Intrusion

118.8 -- (DAE) Attached Encrustation 5%

122.0 -- (IR) Runner Joint

137.3 -- (IG) Gusher

491.8 495.5 (IS) Intruding Sealing Material

0.0 320.3 (SAV) Aggregate Visible

2.0 36.4 (IS) Intruding Sealing Material Yes

91.3 166.1 (IS) Intruding Sealing Material Yes

0.0 71.0 (SAV) Aggregate Visible

4.3 40.8 (CL) Crack Longitudinal Yes

8.4 54.9 (IS) Intruding Sealing Material Yes

314 114A 14A 24 71.0

13 15 114A 24 320.3

12 16 15 24 499.6

9 18 17A 180.9

8 19 18 24 67.6

7 145 19 24 487.4

11 17 16 24 498.8

10 17A 17 24 178.6

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(B9039)

Start (Ft) Finish (Ft) Fracture Hole Surface Damage Lining Failure Deposit Infiltration Obstacle Construction Defect Rehabilitation

Phasing PriorityNotes3Inter-mittent2

Defect Location1Upstream Manhole

Pipe Segment

Downstream Manhole

Diameter (In)

Surveyed Length (Ft)

0.0 98.8 (SAV) Aggregate Visible

0.0 98.8 (CL) Crack Longitudinal Yes

0.0 398.7 (SAP) Aggregate Projecting

147.1 -- (SZ) Other Grout Missing from Joints Throughout Line

0.0 498.7 (SAP) Aggregate Projecting

29.3 177.7 (DSF) Fine

143.0 -- (TBI) Tap Break-In Intruding 6" Intrusion

155.3 182.2 (CL) Crack Longitudinal Yes

316.3 331.6 (IS) Intruding Sealing Material Yes

320.2 -- (SZ) Other Grout Missing from Joint

331.6 -- (IS) Stain Infiltration Stains Throughout Line

402.9 498.7 (SZ) Other Grout Missing from Joint

461.8 -- (TBI) Tap Break-In Intruding 5" Intrusion

461.8 -- (CL) Crack Longitudinal

0.0 400.4 (SAP) Aggregate Projecting

5.9 -- (H) Hole Joint

5.9 -- (IG) Gusher

6.6 400.4 (SZ) Other Grout Missing from Joints Throughout Line

18.4 -- (IS) Stain Infiltration Stains Throughout Line

377.7 395.6 (CL) Crack Longitudinal

392.0 -- (TBI) Tap Break-In Intruding 4" Intrusion

0.2 286.0 (SAP) Aggregate Projecting

11.4 286.0 (SZ) Other Grout Missing from Joint

249.6 272.8 (CL) Crack Longitudinal

2.0 302.3 (SAP) Aggregate Projecting

2.5 -- (IW) Weeper

3.8 302.3 (SZ) Other Grout Missing from Joints Throughout Line

140.2 -- (TBI) Tap Break-In Intruding 6" Intrusion

202.3 281.9 (IS) Stain Yes

302.3 -- (MSA)…