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Date
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August 7, 2006
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Agenda Item No.
9 Roll Call No.
06- Communication No. 06-501 Submitted by: Jeb E. Brewer, P.E. City Engineer and William G. Stowe, Assistant
City Manager/Public Works/
Engineering
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AGENDA
HEADING:
Approving
and authorizing the execution of Iowa Department of Transportation (IDOT)
Change Order No. 2 to Keo Way Phase 2 Storm Sewer Outlet not to exceed City
cost of $124,716.53.
SYNOPSIS:
City
Council approved a preconstruction agreement with IDOT for Keo Way (Birds Run)
Phase 2 Storm Sewer related to I-235.
As part of this agreement, change orders exceeding $25,000 in additional
City contribution must be approved by the Des Moines City Council. Change Order No. 2 in the amount not to
exceed $374,149.58, City share being $124,716.53, is for boring the sewers
underneath the utilities.
FISCAL
IMPACT:
Amount:
$124,716.53
Funding
Source: 2006-2007 CIP, Page Street-23, I-235 Storm
and Sanitary Sewer Improvements, STR197, Storm Sewer Utility Funds.
Amount:
$124,716.53
Funding
Source: Iowa Department of Transportation State
Funds.
Amount:
$124,716.52
Funding
Source: Qwest Communications
ADDITIONAL
INFORMATION:
The
City and IDOT entered into a preconstruction agreement where the City will
repay IDOT an estimated 57% of the storm sewer cost, 100% for any enhanced
storm capacity, and 100% of sanitary sewer cost. The repayment will begin in FY 2007-08. Change orders affecting the City’s final cost will be approved by
the City.
Change Order No. 2 is for the cost to bore 40 lineal feet of 54-inch sanitary sewer with casing and 84 lineal feet of 10 ft. x 5 ft. reinforced concrete box storm (RCB) sewer underneath the Qwest communication utilities. Various alternatives to construct the 54-inch sanitary sewer and 10 ft. x 5 ft. RCB underneath the utilities were discussed between the City, IDOT, and Qwest.
· The first alternative was to perform open cut construction. IDOT’s consultant had chosen this alternative in the original construction documents, as Qwest indicated that their ducts could be supported over the open trench. However, Qwest has determined that their ducts at this location do not have structural integrity to allow the contractor to support the duct bank over the open cut sewer construction; therefore, construction is not feasible as originally planned.
· A second alternative was explored to completely replace the Qwest ducts. Qwest ducts must be reconstructed from access manhole to access manhole, which is approximately 900 feet long from south of Keo Way north to Crocker Street. Construction of the new duct would require several stages of traffic control across Keo Way, additional construction time, and coordination between the two projects.
·
A third
alternative was explored to bore the sanitary and storm sewers under the Qwest
ducts, which would minimize the disruption to traffic flow on Keo Way, meets
the project schedule coordination with IDOT for traffic flow from I-235 this
fall, and does not extend construction time.
This option requires additional cost on the sewer contract. Since this option is beneficial to Qwest as
it eliminates their cost to relocate the duct, beneficial to the IDOT in order
to keep traffic phasing on schedule, and beneficial to the City in order to
minimize downtown access disruptions, all three parties have agreed to share
the cost equally and proceed with this option.
The total change order cost is $374,149.58, with the City’s share being
$124,716.53.
PREVIOUS
COUNCIL ACTION(S):
Date: May
22, 2006
Roll
Call Number: 06-977
Action:
Authorizing
execution of Iowa Department of Transportation Preconstruction Agreement for
Keo Way (Birds Run) Phase 2 Storm Sewer Outlet. (Council
Communication No. 06-294).
Date: August
31, 2000
Roll
Call Number: 00-3634
Action: Approving Iowa Department of Transportation
Predesign Agreement for Interstate 235, from the west City limits to the north
City limits. (Council
Communication No. 00-411).
BOARD/COMMISSION
ACTION(S): NONE
Date:
Board/Commission
Action:
Action:
ANTICIPATED
ACTIONS AND FUTURE COMMITMENTS: NONE