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October 10, 2014 To: WRA Technical Committee Members: Jim Utter, Altoona Mark Mueller, Ankeny Pat Collison, Bondurant Bart Weller, Clive Albert Aguilar, Des Moines Royce Hammitt, WRF David Cubit, Johnston Gary Patterson, Pleasant Hill Bret Vandelune, Polk County David McKay, Urbandale Paul Drey, UWHSD Jason VanAusdall, UWHSD Tim Hoskins, City of Norwalk Duane Wittstock, West Des Moines John Gibson, City of Waukee Mike Shulte, Polk City Anthony Bellizzi, Cumming Re: WRA Technical Committee Meeting (October 14, 2014) A meeting of the WRA Technical Committee has been scheduled for Tuesday, October 14, 2014 at 1:30 p.m. The meeting will be held in the Administration Building Conference Room at the Des Moines Wastewater Reclamation Facility, 3000 Vandalia Road, Des Moines, Iowa. A meeting notice, agenda, and exhibits for the meeting and minutes from the September 9, 2014 meeting are attached. The notice, minutes, exhibits, and agenda will be sent via e-mail. If you have questions please contact me at 223-6231 or Scott Hutchens at 323-8031. Very truly yours, Bart Weller Chairperson WRA Technical Committee BW: STH Attachments
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DES MOINES WASTEWATER RECLAMATION ... OF MEETING DES MOINES WASTEWATER RECLAMATION AUTHORITY TECHNICAL COMMITTEE Des Moines Wastewater Reclamation Facility 3000 Vandalia Road Des Moines,

May 24, 2018

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Page 1: DES MOINES WASTEWATER RECLAMATION ... OF MEETING DES MOINES WASTEWATER RECLAMATION AUTHORITY TECHNICAL COMMITTEE Des Moines Wastewater Reclamation Facility 3000 Vandalia Road Des Moines,

October 10, 2014

To: WRA Technical Committee Members: Jim Utter, Altoona Mark Mueller, Ankeny Pat Collison, Bondurant Bart Weller, Clive

Albert Aguilar, Des Moines Royce Hammitt, WRF David Cubit, Johnston Gary Patterson, Pleasant Hill Bret Vandelune, Polk County David McKay, Urbandale

Paul Drey, UWHSD Jason VanAusdall, UWHSD Tim Hoskins, City of Norwalk Duane Wittstock, West Des Moines John Gibson, City of Waukee Mike Shulte, Polk City Anthony Bellizzi, Cumming

Re: WRA Technical Committee Meeting (October 14, 2014) A meeting of the WRA Technical Committee has been scheduled for Tuesday, October 14, 2014 at 1:30 p.m. The meeting will be held in the Administration Building Conference Room at the Des Moines Wastewater Reclamation Facility, 3000 Vandalia Road, Des Moines, Iowa. A meeting notice, agenda, and exhibits for the meeting and minutes from the September 9, 2014 meeting are attached. The notice, minutes, exhibits, and agenda will be sent via e-mail. If you have questions please contact me at 223-6231 or Scott Hutchens at 323-8031. Very truly yours, Bart Weller Chairperson WRA Technical Committee BW: STH Attachments

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NOTICE OF MEETING

DES MOINES WASTEWATER RECLAMATION AUTHORITY TECHNICAL COMMITTEE

Des Moines Wastewater Reclamation Facility

3000 Vandalia Road Des Moines, Iowa

October 14, 2014

1:30 p.m.

AGENDA

ITEM 1: Call to Order ITEM 2: Roll Call ITEM 3: Minutes for the September 9, 2014 meeting - Approval ITEM 4: WRF Ferrous Chloride Feed System Improvements – Bid Review &

Recommendation ITEM 5: Change Order No. 1 in the Amount of $269,350.00 with S.M. Hentges & Sons, Inc.

for Additional Work Associated with the WRA Southern Tier Interceptor, Phase 10, Segment 17 Project - Information

ITEM 6: Industrial Waste Ordinance – Information ITEM 7: Other Business ITEM 8: Adjourn

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ITEM 03

DES MOINES WASTEWATER RECLAMATION AUTHORITY

TECHNICAL COMMITTEE MEETING MINUTES

Des Moines Wastewater Reclamation Facility

3000 Vandalia Road Des Moines, Iowa

September 9, 2014

1:30 p.m.

ITEM 1: Call to Order Bart Weller, Chair Person, called the September 9, 2014, Technical Committee

meeting to order at 1:30 p.m. ITEM 2: Roll Call Technical Committee Members in Attendance

Jim Utter, Altoona Ken Plager, Ankeny Bart Weller, Clive

Albert Aguilar, Des Moines Tim Hoskins, Norwalk Bret Vandelune, Polk County Shane Kinsey, Johnston Jason VanAusdall, UWHSD Tim Royer, Waukee Royce Hammitt, WRF Others in Attendance Scott Hutchens, Operating Contractor

Tina Grove, Operating Contractor Roxane Vaughan, Operating Contractor

Larry Hare, Operating Contractor Bob Veenstra, Veenstra & Kimm, Inc. Winnie Gleason, Fox Engineering Carl Elshire, MSA Jeff May, Des Moines Karen Oppelt, Altoona Pat Ball, Stanley Consultants Allen Munsterman, Snyder & Associates James Lund, Stanley Consultants

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ITEM 03 ITEM 3: Minutes for the August 12, 2014 meeting - Approval

An error was noted, in the Technical Committee Members City, Shane Kinsey should be with the City of Johnston. The minutes will be amended to reflect the change.

Shane Kinsey made a motion to approve the minutes of the August 12, 2014,

Technical Committee meeting. Bret Vandelune seconded the motion. The motion carried unanimously.

ITEM 4: WRF Ferrous Chloride Feed System Improvements - Project Recommendation

Scott Hutchens explained the Operating Contractor has successfully demonstrated that ferrous chloride addition helps reduce the H2S in biogas from 1,000-4,000 ppm to less than 500 ppm and reduces struvite formation by sequestering phosphorus using iron salts. The engineer’s estimate for this project is $548,500.00, and the project will the project will be funded using the WRA Small Projects & Process Equipment Replacement fund. Bids will be taken on Tuesday, October 7, 2014, and will be presented to the Technical Committee at the October 14, 2014 meeting for review and recommendation to the WRA Board for consideration at the October 21, 2014 meeting.

Tim Royer made a motion to recommend this project to the Board for approval to bid. Bret Vandelune seconded the motion. The motion carried unanimously.

ITEM 5: WRA 2nd & Forest Diversion Structure Rehabilitation - Project Recommendation Scott Hutchens told the group that this improvement includes all labor, materials

and equipment necessary to replace an existing 36-inch buried pneumatic pinch valve with a 36-inch eccentric plug valve. The engineer’s estimate for this project is $104,500.00; bids will be taken on Tuesday, October 7th and presented to the Technical Committee at its October 14, 2014 meeting for review and recommendation to the WRA Board for consideration at its October 21, 2014 meeting. This project is funded from the small capital improvement projects fund

Jim Utter made a motion to recommend this project to the Board for approval to

bid. Ken Plager seconded the motion. The motion carried unanimously ITEM 6: Professional Services Agreement for Design & Construction Phase Services for the

2014 Fourmile Creek Streambank Stabilization Improvements with Snyder & Associates, Inc., in the amount of $220,950.00 – Review & Recommendation

Scott Hutchens reported Snyder & Associates was selected to submit a proposal

because of their extensive knowledge and history of working on the Fourmile Creek Watershed Study and working on similar stream bank restoration projects along Fourmile Creek. A waiver of the WRA’s Consultant Selection Policy for these reasons is requested. The agreement is for work associated with the Clean Water SRF Water Resource Restoration Sponsored Project program project, which the WRA was granted funding for earlier this year.

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ITEM 03 Albert Aguilar made a motion to forward the Professional Services Agreement to

the WRA Board for review and recommendation. Jason VanAusdall seconded the motion. The motion carried unanimously

ITEM 7: Supplemental Agreement No. 7 to the Agreement for Professional Services with the

Iowa Office of the State Archaeologist Granting a Time Extension Until December 31, 2014 for Curation Work and Final Tasks Associated with the WRA Combined Sewer Solids Separation Facility and Supplemental Agreement No. 4 to the Agreement for Professional Services with the Iowa Office of the State Archaeologist Granting a Time Extension Until December 31, 2014 for Curation Work and Final Tasks Associated with the WRA New Main Outfall – Recommendation

Scott Hutchens explained that at this time, OSA has submitted the final report to the WRA prior to the end of the close of business on September 5, 2014, and because they have met the requirements outlined in the sixth supplemental agreement for the CSSSF archaeological work and the fourth supplemental agreement for the New Main Outfall archeological work, OSA is now requesting a time extension to December 31, 2014 for curation work and final tasks. There are no costs associated with the fourth supplemental agreement for archaeological services associated with the New Main Outfall or with the seventh supplemental agreement for archaeological services associated with the CSSSF.

Bret Vandelune made a motion to forward the supplemental agreement to the WRA Board for approval Shane Kinsey seconded the motion. The motion carried unanimously.

ITEM 8: WRA New Main Outfall, Phase 17, Segment 8 Change Order No.1 with S.M.

Hentges & Sons, Inc. for Work Associated with the Elm Street Combined Sewer connection and City of Des Moines Grit Chamber Abandonment in the amount of $311,325.05 – Recommendation

Scott Hutchens told the group that the current plans for the WRA New Main Outfall, Phase 17, Segment 8 project do not address the re-routing of the flows from the Elm Street Combined sewer to the Des Moines River Outfall. To allow the WRA New Main Outfall, Phase 17, Segment 8 project to proceed, this connection must be made. In addition to the Elm Street sewer connection, this change order includes work to abandon the City of Des Moines’s Grit Chamber on the West Side Trunk. The abandonment of the Grit Chamber was contemplated after the award of the WRA New Main Outfall, Phase 17, Segment 8 project. This additional work was requested by the City of Des Moines to address ongoing concerns with the Grit Chamber. The City of Des Moines has reviewed and is an agreement with the proposal from S.M. Hentges for this work. All costs for work associated with the Grit Chamber will be reimbursed to the WRA by the City of Des Moines after the work has been completed.

Jim Utter made a motion to forward the Change order to the Board for approval David McKay seconded the motion. The motion carried unanimously.

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ITEM 03 ITEM 9: Biomethane Injection Project – Information

Royce Hammitt explained that The Des Moines Metro Wastewater Reclamation Facility produces biogas, a 63% methane fuel, which is used to produce on-site heat, electrical power, and is sold to Cargill for use as a substitute fuel in their process steam boiler. Biogas produced beyond that need for the above purposes is flared in a waste gas burner. Since 2011 WRF has worked to evaluate additional beneficial uses for biogas and will soon have two additional reciprocating engine generators that can operate using biogas. The WRF is conducting a marketing study and economic analysis. The biogas upgrade plant could be located either within the current WRF or at a nearby WRA owned property known as 3125 Vandalia Road.

ITEM 10: Industrial Waste Ordinance – Information

Larry Hare reported that 53 inspections were completed in the month of August and that most of these occurred in downtown Des Moines, Norwalk, Johnston, and Altoona. He also added that there one physical Constraint which was approved.

ITEM 11: Other Business Scott Hutchens announced that the CSSSF was turned on Sunday, September 9,

2014, and operated as intended with a few minor glitches. ITEM 12: Adjourn Moved by Bret Vandelune and seconded by Royce Hammitt to adjourn the meeting.

The motion carried unanimously. Meeting adjourned at 1:57 p.m.

tmg

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Item 04

Memorandum October 10, 2014 To: WRA Technical Committee From: Scott Hutchens Re: WRF Ferrous Chloride Feed System Improvements - Contract Recommendation The improvement includes all labor, materials and equipment necessary for the installation of a permanent ferrous chloride feed system in the Sludge Processing Building (Building 70) and electrical modifications in the Power Generation Building (Building 75) at the Wastewater Reclamation Facility. Work includes demolition, site improvements, structural modifications, bulk storage tank installation, chemical feed piping, pump, accessories, electrical modifications, and miscellaneous associated work, including cleanup, all in accordance with the contract documents. The engineer’s estimate for this project was $548,500.00, and bids were taken on October 7, 2014. Six bids were received and are tabulated below. Weidner Construction (Marshalltown, Iowa) $480,000.00 Woodruff Construction LLC (Ames, Iowa) $489,700.00 Brocon Services LLC (Johnston, Iowa) $495,000.00 Building Crafts, Inc. (Wilder, Kentucky) $570,863.00 Neuvirth Construction, Inc. (Blair, Nebraska) $595,000.00 Jasper Construction Services (Newton, Iowa) $605,400.00 Weidner Construction of Marshalltown, Iowa is the apparent low bidder with a bid of $480,000.00 which is 12.49% under the engineer’s estimate. With a recommendation from the WRA Technical Committee, the Operating Contractor anticipates having the item brought before the WRA Board at the October 21, 2014 WRA Board Meeting for approval. The project should be fully completed by April 30, 2015, and the project will be funded with WRA Small Capital Improvement funding (WRA106).

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DEPARTMENT OF ENGINEERING Activity ID 04-2015-001CITY OF DES MOINES, IOWA IDOT Project No: None

Bid Date: 10/7/14TABULATED BY: J. Beck APPROVED BY_______________________CHECKED BY: _______________________

CONTRACTOR'S BID TABULATION PROJECT: WRF Ferrous Chloride Feed System Improvements

----------------------------------------------------------------------ESTIMATE-----------------------------------------------------------------------

UNIT UNIT UNIT UNITITEM DESCRIPTION QUANTITY PRICE AMOUNT PRICE AMOUNT PRICE AMOUNT PRICE AMOUNT

1 WRF Ferrous Chloride Feed System Improvements 1 LS $548,500.00 $548,500.00 $480,000.00 $480,000.00 $489,700.00 $489,700.00 $495,000.00 $495,000.00

TOTAL CONSTRUCTION COST $548,500.00 $480,000.00 $489,700.00 $495,000.00PERCENT OF ENGINEER'S ESTIMATE -12.49% -10.72% -9.75%

Apparent Low Bidder

BID PRICE

1920 Philadelphia StreetSuite 102

Ames, Iowa 50010515-232-4535

Johnston, Iowa 50131515-278-2650

Suite 4

BID PRICE

BID SECURITY10% of Bid BID PRICE

10% of Bid

Marshalltown, IA 50158641-752-6665

10% of Bid

Brocon Services LLC6200 NW Beaver Drive

BID SECURITY BID SECURITY

Weidner Construction2607 255th Street

Woodruff Construction LLC

Page 1

Page 9: DES MOINES WASTEWATER RECLAMATION ... OF MEETING DES MOINES WASTEWATER RECLAMATION AUTHORITY TECHNICAL COMMITTEE Des Moines Wastewater Reclamation Facility 3000 Vandalia Road Des Moines,

DEPARTMENT OF ENGINEERING Activity ID 04-2015-001CITY OF DES MOINES, IOWA IDOT Project No: None

Bid Date: 10/7/14TABULATED BY: J. Beck APPROVED BY_______________________CHECKED BY: _______________________

CONTRACTOR'S BID TABULATION PROJECT: WRF Ferrous Chloride Feed System Improvements

----------------------------------------------------------------------ESTIMATE-----------------------------------------------------------------------

UNIT ITEM DESCRIPTION QUANTITY PRICE AMOUNT

1 WRF Ferrous Chloride Feed System Improvements 1 LS $548,500.00 $548,500.00

TOTAL CONSTRUCTION COST $548,500.00PERCENT OF ENGINEER'S ESTIMATE

UNIT UNIT UNITPRICE AMOUNT PRICE AMOUNT PRICE AMOUNT

$570,863.00 $570,863.00 $595,000.00 $595,000.00 $605,400.00 $605,400.00

$570,863.00 $595,000.00 $605,400.00+4.08% +8.48% +10.37%

$58,000 Bond 10% of Bid 10% of Bid BID PRICE BID PRICE BID PRICE

BID SECURITY BID SECURITY BID SECURITY

Wilder, Kentucky 41076 Blair, Nebraska 68008 Newton, Iowa 50208859-781-9505 515-480-7200 641-792-8650

Building Crafts, Inc. Neuvirth Construction, Inc. Jasper Construction Services2 Rosewood Drive 7386 Co. Rd. P35 928 N. 19th Ave. E.

Page 2

Page 10: DES MOINES WASTEWATER RECLAMATION ... OF MEETING DES MOINES WASTEWATER RECLAMATION AUTHORITY TECHNICAL COMMITTEE Des Moines Wastewater Reclamation Facility 3000 Vandalia Road Des Moines,

Item 5

Memorandum October 14, 2014 To: WRA Technical Committee From: Scott Hutchens Re: Change Order No. 1 in the Amount of $269,350.00 with S.M. Hentges &

Sons, Inc. for Additional Work Associated with the WRA Southern Tier Interceptor, Phase 10, Segment 17 Project - Information

On October 6 the WRA Board held a special meeting to consider Change Order No.1 in the Amount of $269,350.00 with S.M. Hentges & Sons, Inc. for Additional Work Associated with the WRA Southern Tier Interceptor, Phase 10, Segment 17 Project. In the best interest of the WRA staff decided to initiate the process to have a special WRA Board meeting to consider Change order No.1 knowing the Technical Committee would not meet prior to the WRA Board action on the change order. The WRA Board passed Change Order No.1 at the special meeting. This item is now be presented to the Technical Committee as an informational and discussion item.  As part of the WRA Southern Tier Interceptor, Phase 10, Segment 17 project, the contractor was required to tunnel approximately 515 feet under Highway 5 to allow a new 16” and 30” force mains to be installed. The contractor began installing the tunnel and advanced the tunnel approximately 62 feet before encountering large pieces of concrete debris. Upon encountering the debris, the contractor began experiencing delays and requested direction from the WRA on how to proceed. The WRA instructed the contractor to proceed and indicated that the debris encountered would be addressed under the WRA’s Tunneling specification.

The contractor resumed their effort to install the tunnel but continued to encounter large debris creating major delays. After advancing the tunnel an additional eight feet the contractor again suspended their operation and requested discussion on the matter with the WRA. The contractor provided their observations of the debris encountered in the tunnel and the WRA gathered additional information as to how and why the debris may have been placed under the highway. The WRA’s research indicated that the Iowa Department of Transportation allowed their roadway contractor to place a Class 12 backfill at the base of the embankment. The allowable material in a Class 12 backfill included the materials consistent with what the WRA’s tunneling contractor had been encountering. Based on the information gathered by the WRA and its contractor, it has been determined that there is a very high likelihood that the contractor will continue to encounter similar

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Item 5

debris throughout the entire length of the tunnel and that proceeding with the current tunnel operation would be economically impracticable for the WRA’s contractor. The Operating Contractor’s staff has determined that it is in the best interest of the WRA to instruct the contractor to abandon the current tunnel operation and begin a new tunnel operation at an alternative location. The WRA has performed additional research and chosen an alternative location for the tunnel which is believed to have the least likelihood of encountering conditions that would prevent a successful tunneling operation. The Operating Contractor’s Staff and Veenstra & Kimm, Inc. have reviewed the work items and costs from S.M. Hentges & Sons, Inc. to abandon the current tunnel and construct a new tunnel at an alternative location under Highway 5 and are in agreement with the work items and costs. The attached change order is full compensation to the contractor for additional costs associated with the above noted item. Also attached is a letter from Veenstra & Kimm that has additional information regarding this change order.

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Existing Southern Tier Interceptor

Proposed Southern Tier InterceptorPhase 10, Segments 15-17

End Segments 15 &16(Gravity Sewer)

End Segment 17(Force Main)

----------------------------------------Begin Segments 15 &16

(Gravity Sewer)

Begin Segment 17(Force Main)

Southern Tier High LiftPump Station Upgrades

(Separate Project)0 1,250 2,500 3,750 5,000625

Feet

WRA Southern Tier InterceptorPhase 10, Segments 15-17 Location Map

/

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VEENSTRA & KIMM, INC. 3000 Westown Parkway • West Des Moines, Iowa 50266-1320

515-225-8000 • 515-225-7848(FAX) •800-241-8000(WAT5)

September 30, 2014

Dave L. Miller WRA Director City of Des Moines 3000 Vandalia Road Des Moines, Iowa 50317

WASTEWATER RECLAMATION AUTHORITY SOUTHERN TIER INTERCEPTOR PHASE 10, SEGMENT 17 ACTIVITY ID NO. 07-2012-011 HIGHWAY 5 TUNNEL RECOMMENDATION FOR ABANDONMENT CHANGE ORDER RECOMMENDATION

Approximately two weeks ago The Driller, LLC, a subcontractor to S.M. Hentges & Sons Co., Inc. started the tunnel under Highway 5 as part of the construction of the WRA Southern Tier Interceptor Phase 10, Segment 17 project. The tunnel is 515 feet long and encompasses the roadway and significant fill sections on both the north and south side of Highway 5. The tunnel extends well beyond the right-of-way of Highway 5 due to the height of the fill sections.

For the first several days the contractor was able to make reasonable progress for tunneling. The contractor indicated it bid the project anticipating would be able to progress at a rate of approximately 20 feet per day. While the progress during the first week of tunneling was somewhat slower than the subcontractor anticipated the subcontractor expressed no concern regarding the tunnel. Early in the week of September 22, 2014 the contractor began to encounter what appear to be buried concrete at the fact of the tunnel. Concrete became more significant shortly after it was encountered.

During the week of September 22, 2014 the contactor spent approximately three full days trying to chip, saw, and otherwise remove various pieces of concrete encountered at the face of the tunnel. Because the contractor opted to use a single 51-inch diameter casing pipe it was possible for the contractor to work at the face of the tunnel to remove the concrete. _ _ _

SEP 10 2014

West Des Moines • Coralville • Omaha .Moline • Mason City • Sioux ciy • u&FQT OF PUBLIC WORKS CITY OF DES MOINES, IOWA

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Dave Miller September 30, 2014 Page 2

Through approximately three full days of work during the week of September 22, 2014 the contractor was able to progress the tunnel by approximately 8 feet. Before the contractor encountered the concrete it was able to tunnel 62 feet and after encountering the concrete, the contractor was able to tunnel 8 feet in about the same length of time.

What became apparent from observation of the concrete during the week of September 22, 2014 was the material was not casual deposits of concrete and did not appear to be the type of concrete that would be placed along a road or stream bank for stabilization. The concrete pieces tended to be arrayed horizontally and were tightly packed in clay. The concrete appeared to be in the nature of an engineered fill section rather, than casual debris or concrete.

It appeared there were three possible sources for the concrete that were identified by various parties. One source of the concrete was thought to be the old road leading to the Area B Wastewater Treatment Facility and the WRA Southern Tier Pump Station. The concrete was encountered approximately 75 feet to 90 feet west of the road and the road to the treatment plant and pump station was never paved with concrete. This source of the concrete appears to have been eliminated due to location and the nature of construction of the original road.

The second possible source of the was concrete or riprap that had been placed along the small south flowing stream channel located in the vicinity of the tunnel. A comparison of coordinates would suggest the tunnel was in relatively close proximity to the creek. One set of coordinates suggested the tunnel was coincident with the location of the creek, while another set of coordinates suggested the tunnel was located just the east of the creek. It is known the channel was stabilized in some areas in the vicinity of the project. However, the type of material excavated was not consistent with what would be encountered in a creek stabilization. While creek stabilization could not be fully eliminated as the source of the concrete it appears very unlikely the concrete was from a creek stabilization.

The third possible source is if the concrete fill material placed by the Iowa Department of Transportation when Highway 5 was constructed about 1999. In this area Highway 5 is constructed on a significant fill section.

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Dave Miller September 30, 2014 Page 3

Originally the Iowa Department of Transportation indicated they did not have any records of the type of fill in the area. Later the Iowa Department of Transportation indicated the construction inspector's diary suggests Class 12 material, including buried debris, was placed in this area. The Iowa Department of Transportation records suggest the debris is from the demolition of farmsteads and out buildings in this area. The Iowa Department of Transportation records do not indicate the placement of concrete. However, the material observed clearly appears to be consistent with Class 12 embankment that would allow for the placement of concrete in clay fill.

Observation of the concrete suggests it is not from a local source involved with demolition in the general area. The concrete that was observed included 8-inch reinforced concrete street pavement, sidewalk sections of approximately 4-inch thickness and other pieces of concrete suggesting it was removed from a concrete street with curb and gutter. The concrete appears to be more associated with a street removal and not with the type of demolition that occurred as the Iowa Department of Transportation cleared the right-of-way for the Highway 5 corridor. In this area the Highway 5 corridor was undeveloped and any debris that would have been encountered from the demolition of farmsteads was not of the nature observed.

The Iowa Department of Transportation has not been able to provide any specific information concerning the scope and extent of the fill. The Iowa Department of Transportation has made anecdotal comments suggesting there could be fairly extensive fill material in this area. The scope and extent of the fill could not be determined from the conversations and exchange of information with the Iowa Department of Transportation.

The contract for the WRA Southern Tier Interceptor Phase 10, Segment 17 project utilizes the WRA's standard contract language. This standard language excludes the language in the Statewide Urban Standard Specifications referred to as the changed site condition provision. The contract language includes the WRA's standard provision that would provide for payment if the contractor encountered boulders or other casual rocks during the tunneling. This language was added to the contract several years ago at the request of the subcontractor involved with this tunnel.

Under the contract documents the contractor and tunneling subcontractor bear the risk of unforeseen conditions that would be encountered during construction. The only explicit remedy under the contract would be the payment of $3,000 each for up to eight boulders for an amount totaling $24,000. This amount for boulder payment is made after the contractor is responsible for the first boulders encountered. Also, any boulders in excess of the initial allowance and eight compensable boulders under the contract are the responsibility of the contractor.

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Dave Miller September 30, 2014 Page 4

The concrete encountered during construction would not be considered a boulder under the definition in the contract. On previous projects the WRA has been willing to be flexible in defining a boulder if the contractor encounters a condition that would be considered similar to a boulder, but would not meet the definition of a boulder.

Not explicitly set forth in the contract are common law concepts of impracticability or impossibility. While the WRA contract language excludes the standard changed site condition language that derived from federal contract law, the WRA has recognized the concepts of economic impracticability and impossibility.

Economic impracticability is generally defined as a condition is which the work could physically be completed, but the economic impact on the contractor to complete the work under those conditions is so onerous as to require relief under the contract. This slightly differs from impossibility under which the contractor could not construct the project as it currently is designed.

Based on the information available from the Iowa Department of Transportation it is anticipated there will be more extensive buried debris in the tunnel path, including the possibility of concrete. The location of the tunnel is near the interface with the natural ground surface. This would be the most likely area where the contractor would place hauled in debris for incorporation in Class 12 backfill. Although it cannot be determined with any degree of certainty there appears to be a high risk the contractor could encounter continuing deposits of concrete and debris as it progressed forward.

With respect to the tunnel there are two separate, but related, issues that need to be addressed.

The first issue is the question of what is the appropriate course of action for the tunnel. One option would be to continue forward with the tunnel as it is constructed eventually working through the remaining 445 feet of the tunnel. If the contractor encountered debris in the balance of the tunnel face at the rate of progress the contractor made during the week of September 22, 2014 there would be approximately 38 weeks to complete the tunnel resulting in a total duration of the tunnel of 39 weeks, compared to the approximately 5 weeks the contractor anticipated to complete the tunnel.

The alternative to continuing the tunnel would be to abandon the existing tunnel and to start construction at a new tunnel location. Options were evaluated to shift the tunnel to the east or west as well as options to shift the tunnel to a higher elevation or to a lower elevation.

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Dave Miller September 30, 2014 Page 5

Any of the tunnel options that remain at or above the original wound elevation appear to have the same type of risk of encountering debris as the existing tunnel. Although there are several options available for an alternative location at or above the same elevation as the tunnel, all of these options were considered to be at the same risk as the existing tunnel.

The other option involved lowering the tunnel to an elevation below the natural ground elevation. Although this approach would require additional changes in the force main the available evidence would suggest the fill material placed by the Iowa Department of Transportation contractor was probably at or above the natural ground elevation. Lowering the pipe appears to reduce the likelihood of encountered buried debris in the tunnel. If a new tunnel is to be constructed at a lower elevation it will be necessary to move the tunnel away from the current location. The preferred approach appears to be shifting the tunnel east approximately 75 feet. This shift would place the tunnel well away from the old creek channel and would minimize the risk of encountering buried debris associated with the creek channel.

There are advantages and disadvantages of both continuing the existing tunnel and starting a new tunnel. The advantage of continuing the existing tunnel is the ability to use the 70 feet of tunnel already constructed. On the other hand, continuing construction in the area of the debris raises the potential for the tunnel to eventually fail due to the inability to remove debris in the tunnel face. Although the contractor has been successful in removing the concrete and debris at the tunnel face there is no assurance that will continue for the balance of the construction. For at least one of the pieces of concrete encountered it was questionable whether the contractor would be able to remove the concrete and push the casing pipe past the debris. The contractor was successful at that location, but there is a serious question whether that would be the case in all of the future debris that would be encountered.

The risk of a new tunnel is the conditions encountered would be similar to those encountered in the existing tunnel and starting a new tunnel would not improve the tunneling conditions.

It appears the conditions currently being encountered by the contractor are not likely to yield a successful tunnel. While the contractor was able to advance 8 feet with at least one of the concrete pieces risking a failure the probability of the contractor completing the remaining 400 plus feet of the tunnel is believed to be relatively low.

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Dave Miller September 30, 2014 Page 6

The likelihood of a successful tunnel appears to be much greater if the tunnel is lowered to an elevation below the original ground elevation where the likelihood the Iowa Department of Transportation contractor placed engineered fill material is much lower. The available evidence would suggest the contractor placed fill primarily above the natural ground surface and that tunneling below the natural ground surface would have a much lower risk of encountering debris and concrete.

On balance, the preferred alternative would be to abandon the existing tunnel and to construct a new tunnel approximately 75 feet east with the new tunnel being located at least 7 feet below the natural ground before the construction of Highway 5. While this change affects the construction of the force main it appears to be an alternative that is the most likely to succeed as it relates to the tunnel.

Construction of the new tunnel would be completed at the unit price in the contract as that work would be identical to the original tunnel. If the existing tunnel is abandoned there will be a cost to the contractor to abandon the tunnel. The cost for abandoning the tunnel includes the contractor's original unit price for labor and materials to install the 70 feet of tunnel, less the casing pipe and carrier pipe that can be reused in the new tunnel. There is the question of the time spent during the week of September 22, 2014 when the contractor progressed only 10 feet in one week of work. The contractor's labor and equipment costs for this 10 feet would be significantly higher than the costs incorporated in the standard unit price.

The contractor incurred a cost to construct the tunnel pit that will be abandoned. This effectively requires the contractor to build a new tunnel pit.

The contractor will need to remove the tunnel casing pipe in the failed tunnel in order to retrieve the $500,000 plus tunnel machine at the head of the tunnel. The contractor will incur a cost for removing this casing pipe and tunnel machine. Lastly, the contractor will need to fill the failed tunnel hole that extends approximately 70 feet into the tunnel.

The contractor will incur additional costs for a deeper tunnel pit at the new location. The force main will need to be modified to the new location of the tunnel. The new location of the force main will require additional bends and pipe joint restraints.

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Dave Miller September 30, 2014 Page 7

The preliminary cost provided by the contractor for the changes is as follows:

1. 70 feet of tunneling at $975/foot $ 68,250 2. 3.5 days labor and equipment $ 22,000 3. Tunnel pit excavation and backfill $ 35,000 4. Removal of casing pipe and tunnel machine $ 20,000 5. Flowable fill in existing tunnel hole $ 21,000 6. 40' of 30" restrained joint force main $ 14,000 7. 40' of 16" restrained joint force main $ 2,800 8. 4 30" Mi bends $ 20,000 9. 4 16" MJ bends $ 6,000 10. Additional depth of new pit $ 15,000 11. Alignment change on north side of Highway 5 $ 13,000 12. Overhead and profit $ 17,300

TOTAL $269,350

The second question to address is whether under the contract the WRA would be responsible for the cost of the abandonment of the tunnel. On some previous projects when the contractor has encountered difficulty in construction the WRA has determined those difficulties are in the nature of a changed condition and would not be compensable under the contract. When the contractor has encountered difficult construction conditions, such as the encountering of buried trees on the WRA West Des Moines Outfall or encountering a buried shale formation on the WRA Southwest Area Diversion Facility Phase 22, Segment 5, the WRA has determined those conditions are in the nature of what would normally be considered contractor's responsibility as they are costly, but not economically prohibitive or impossible.

On other projects when the contractor has encountered conditions that would not allow for construction or would be so difficult as to be impracticability the WRA has determined it is appropriate for it to provide compensation to the contractor under the doctrine of impracticability or impossibility. The most recent example where the WRA determined conditions were impracticable or impossible was a tunnel on the Four Mile Interceptor. On that project the WRA determined the conditions were such the contractor either could not physically complete the construction or the construction would be so difficult and costly that it was impracticable.

Based on the contract documents and the WRA's past practice it appears the appropriate test is to determine whether the conditions encountered would be considered in the nature of a changed site condition, which is not compensable under the WRA contract or is in the nature of a impracticable or impossible construction which would be considered compensable under the contract.

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Dave Miller September 30, 2014 Page 8

Although the WRA has not established a bright line test for determining the difference between a changed condition and an impracticable or impossible condition the WRA has generally looked at the nature of the conditions encountered in the tunnel in relationship to the overall scope and magnitude of the tunnel.

On projects where the WRA has determined the conditions encountered were in the nature of a changed site condition there was a clear definition to the extent of the conditions encountered on those projects. It was fairly certain once the obstruction was cleared the contractor could complete the tunnel. That does not appear to be the case for this tunnel as at this time it is entirely unknown what the conditions the contractor will encounter in the balance of the tunnel.

On the project on the Four Mile Interceptor involving the tunnel under the railroad the conclusion reached was the conditions encountered were such that tunneling could not be considered a viable alternative. In that instance the WRA changed the construction to open cut construction and compensated the contractor on the basis the tunnel was impossible or such an economic impracticability as to be the equivalent of an impossible form of construction.

The conditions encountered on the tunnel under Highway 5 appear to be much more in line with the conditions encountered on the railroad tunnel on the Four Mile Interceptor than conditions encountered on other tunnels where the WRA has determined the conditions are non-compensable.

On balance, it appears the WRA's practice with respect to. this type of condition would be consider the conditions encountered to be compensable under the contract not as a changed site condition, but either as an impracticability or impossibility for which relief would be implied under the general concept of construction law and not under the specific language of a changed site condition clause.

If the WRA is in agreement with this interpretation the change order to compensate the contractor for the cost of the failed tunnel would be appropriate. The contractor would be made reasonably whole for the cost incurred for the failed tunnel.

The contractor would be responsible to construct the tunnel at the new location and profile. The contractor's responsibility under the contract for the new tunnel would be the same as the existing tunnel and would be subject to the no changed site condition clause so the only relief would be if the contractor encountered a second instance of conditions that would compensable under the concept of impracticability or impossibility.

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Dave Miller September 30, 2014 Page 9

The writer would note if the second tunnel is completed successfully and no boulders are encountered the contractor would not be paid the cost in the contract for the boulders. The $24,000 boulder cost is included in the contract cost. If the contractor is able to complete the work without encountering boulders the net cost of the tunnel could decrease by the savings on the boulders.

If you have any questions or comments concerning the project, please contact the writer at 225-8000.

VEENSTRA & KIMM, INC.

H., R. Veenstra Jr.

H RVJ r: pj h 40063 cc: Scott Hutchens

Eugene Schmitt Nick Carter

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DES MOINES METROPOLITAN

WASTEWATER RECLAMATION AUTHORITY

OPERATING CONTRACTOR - CITY OF DES MOINES

WASTEWATER RECLAMATION FACILITY

3000 VANDALIA ROAD

DES MOINES, IOWA 50317-1346

ENGINEERING DEPARTMENTCITY OF DES MOINES, IOWA

CHANGE ORDER AGREEMENT NO. 1

Date:

Contractor:

Project: Activity ID: 07-2012-011WRA Southern Tier Interceptor, Phase 10,

Segment 17

INITIATED BY: Engineering

S. M. Hentges & Sons Inc.

September 30, 2014

DESCRIPTION OF CHANGE ORDER AND PURPOSE

1.01) Relocation of Tunnel Under Highway 5: As part of the WRA Southern Tier Interceptor, Phase 10,

Segment 17 project, the contractor was required to tunnel approximately 515 feet under Highway 5 to allow a

new 16” and 30” force mains to be installed. The contractor began installing the tunnel and advanced the

tunnel approximately 62 feet before encountering large pieces of concrete debris. Upon encountering the

debris, the contractor began experiencing delays and requested direction from the WRA on how to proceed.

The WRA instructed the contractor to proceed and indicated that the debris encountered would be addressed

under the WRA’s Tunneling specification.

The contractor resumed their effort to install the tunnel but continued to encounter large debris creating major

delays. After advancing the tunnel an additional 8 feet the contractor again suspended their operation and

requested discussion on the matter with the WRA.

The contractor provided their observations of the debris encountered in the tunnel and the WRA gathered

additional information as to how and why the debris may have been placed under the highway. The WRA’s

research indicated that the Iowa Department of Transportation allowed their roadway contractor to place a

Class 12 backfill at the base of the embankment. The allowable material in a Class 12 backfill included the

materials consistent with what the WRA’s tunneling contractor had been encountering.

Based on the information gathered by the WRA and its contractor, it has been determined that there is a very

high likelihood that the contractor will continue to encounter similar debris throughout the entire length of the

tunnel and that proceeding with the current tunnel operation would be economically impracticable for the

WRA’s contractor.

The Operating Contractor’s staff has determined that it is in the best interest of the WRA to instruct the

contractor to abandon the current tunnel operation and begin a new tunnel operation at an alternative location.

The WRA has performed additional research and chosen an alternative location for the tunnel which is

believed to have the least likelihood of encountering conditions that would prevent a successful tunneling

operation.

The Operating Contractor’s Staff and Veenstra & Kimm, Inc. have reviewed the work items and costs from

S.M. Hentges & Sons, Inc. to abandon the current tunnel and construct a new tunnel at an alternative location

under Highway 5 and are in agreement with the work items and costs.

The attached change order is full compensation to the contractor for additional costs associated with the above

noted item.

SETTLEMENT FOR COST OF CHANGED WORK

CHANGE ORDER AGREEMENT NO. 1Activity ID 07-2012-011 Page 1 of 3

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ITEM DESCRIPTION UNITS UNIT PRICE AMOUNT

B. ITEMS FOR WHICH CONTRACT UNIT PRICES ARE NOT ESTABLISHED:

1.01 Relocation of Tunnel Under Highway 5 $269,350.00 $269,350.00 1.0000 LS

NET CHANGE PART B $269,350.00

$269,350.00 TOTAL

Original Contract Amount

Previous Change Orders

Amount of Change By This Change Order

New Contract Amount Including This Change Order

Percentage of Change Orders to Original Contract

$2,234,941.75

$0.00

$269,350.00

$2,504,291.75

12.05%

Nicholas F. Carter, P.E.

Civil Engineer 1

Date Pamela S. Cooksey, P.E. Date

Des Moines Interim City Engineer

David L. Miller, P. E.

WRA Director

DateS. M. Hentges & Sons Inc. Date

WRA Board Resolution No. Date

Distribution: Original - Project File

Copy - Prime Contractor

Copy - Contract Compliance

Copy - Finance Department

Copy - Inspection

Nicholas F. Carter, P.E.Copy -

Civil Engineer 1

Copy - Bob Veenstra - Veenstra & Kimm,

Inc.

FUNDING INFORMATION

CIP Page

Object Code

Organization

Project

Activity ID

32

543040

WR809855

WR103a

072012011

Reviewer

Adequate

Transfer $

Object Code

Organization

Project

CHANGE ORDER AGREEMENT NO. 1Activity ID 07-2012-011 Page 2 of 3

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Relocation of tunnel under Highway 5 due to obstructions creating an impracticable condition preventing

contractor from completing the original tunnel.

CHANGE ORDER AGREEMENT NO. 1Activity ID 07-2012-011 Page 3 of 3