1b. Approve Contract Amendment No. 3 for West 78th St Detachment and Downtown Improvements C ITYOF
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CHANHASSEN
' 690 COULTER DRIVE • P.O. BOX 147 • CHANHASSEN, MINNESOTA 55317
(612) 937 -1900 • FAX (612) 937 -5739
MEMORANDUM
TO: Don Ashworth, City Manager
FROM: Charles Folch, Director of Public Works /City Engineer
' DATE: October 5, 1993 `' }
' SUBJ: Approve Contract Amendment No. 3 for West 78th Street Detachment and
Downtown Improvements
During the process of constructing the new roadway embankment along Powers Boulevard
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' (County Road 17) in the transition area from the four -lane urban section to the two -lane rural
section north of West 78th Street, poor existing subsoil conditions were encountered. Upon
further investigation, via test pits and soil borings conducted performed by the project's
' geotechnical engineers, Braun Intertec. It was determined that the extent of the poor subsoil
conditions along the roadway embankment was approximately 250 feet long with maximum
depths of 50 to 60 feet. It is apparent that the fuluvially deposited subsoil material through this
' section of County Road 17 is very loosely compacted and would be highly susceptible to
settlement with the additional embankment loading associated with the road widening.
' Over the past two months, the project engineer, geotechnical consultants, Carver County engineer
and City staff have meet a number of times to discuss this subsoil problem and how it might be
remedied yet still be able to accomplish the needed roadway improvements associated with the
' project. A number of options were evaluated ranging from implementing a direct surcharge of
the area which would require County Road 17 to be closed for nearly two years, to the use of
light - weight fill on the embankment slope which was found to economically unfeasible for this
application. It was the general consensus of this group that the recommended solution involve
minimizing the additional embankment load by steepening the side slopes and implementing a
uniaxlial grid reinforcement to provide internal stability of the slope. The process will involve
' installing grid layers with intermediate lifts of compacted fill material. Installation of the
embankment slope stability grid will require that a portion of the city's existing watermain along
County Road 17 be relocated approximately 15 feet further east through this area.
A cost ro osal consisting of specific work items and associated unit prices has been prepared
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for the soil correction and watermain relocation. The total cost for this work is estimated to be
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I Don Ashworth
October 5, 1993
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1 $54,850.17. It is important to note that had this limited poor soil area been discovered during
the design phase of this project, it still would have had to have been resolved by corrective
measures such as the one being proposed and would not have made an economic difference
1 whether this work was included as a part of the original plan or accomplished through as a
project change order. In any case, this proposed soil correction work will probably allow County
Road 17 to be paved and opened up prior to freeze up this fall.
I It is therefore recommended that contract amendment char a order no. 3) for the West 78th
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Street Detachment and Downtown Improvement No. 92 -3 for the watermain relocation and soil
I corrective work on County Road 17 (Powers Boulevard) in the amount of $54,850.17 be
approved. This revised contract amount wi9a4 be $2,733,718.31.
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I Attachment: Change Order No. 3
c: Dave Hempel, Assistant City Engineer
I Jim Dvorak, SRF
David Juliff, SRF
Randy Reiner, C.S. McCrossan
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OCT- T.- .33 TUE 3:06 SRF P.0
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SRF No. 0921634
October 5, 1993 1
CHANGE ORDER NO. 3 1
City of Chanhassen 1
690 Coulter Drive 1
P.O. Box 147
Chanhassen, Minnesota 55317
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PROJECT: West 78th Street 1
Chanhassen Project No. 92 -3
S.A.P. NO. 10-617 -10 I
CONTRACTOR: C.S. McCrossan, Inc. I
Maple Grove, Minnesota
WHEREAS: The City of Chanhassen desires the construction of the west I
embankment of Powers Boulevard to be reinforced with geotextile
fabric, due to the extremely poor soil conditions discovered during
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construction.
THEREFORE: In accordance with the terms of the contract, you are hereby 1
authorized and instructed to construct the west embankment of
Powers Boulevard, and to relocate the existing watermain as I
shown on the attached drawings. Payment will be based on the
unit prices as itemized below:
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I C'CT- 5-9:3 TUE 3 : OE SRF P - 0.
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1 - 2 _ October 5, 1993
Change Order No. 3
1 * *INCREASE **
Lterr!.NQ Item pescriptitZn n
Lionlity Unit Price Total Price
1 Wat rm ain Relocatinn 4 148.13 $ 592.52
0504.602 12" x 22 1/2 Degree Bend Each . 599 52
0504.603 12" DIP CL 52 Lin, Ft. 40 $ 18.73 $
0504.601 Labor & Equipment Lump Sum 1 $$8,7240.00 . ,740.00
I 0504.601 Flush & Chlorinate Lump Sum
1 m.. nkm - n i h -.ark
0105.609 eogrid Sq. Yd. 1,820 $ 5.21 $ 9,482.20
I 2105.501 Common Excavation (EV) Cu. Yd. 5,625 $ 4.46 $ 25,
2021.501 Mobilization 9,393.75
0105.603 Place Geogrid /Backfill Cu.
um Sum 5 1 $ 575.00 $ 575.00
Lump
1 Total Increase in Contract Amount $ 54,850.17
(Change Order No. 3)
1 Previous Increases in Contract Amount $ 55,719.66
1 Original Contract Amount
$2,623,148.48
Revised Contract Amount
$2,733,718.3
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ISSUED BY;
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STRGAR- ROSCOE- FAUSCH, INC. DATE
1 ACCEPTED:
1 C.S. McCROSSAN, INC. DATE
1 APPROVED;
1 CITY OF CHANHASSEN DATE