University Ave Embankment Failure funding
D~~~E
~Yk-~
MEMORANDUM
January 25, 2006
TO: The Honorable Mayor and City Council Members
FROM: Michael C. Van Milligen, City Manager
SUBJECT: ER Project No. ER - 2100 (636) -- 58 - 31
University Avenue Embankment Failure
ER Funding - Betterment Cost Justification
I respectfully recommend Mayor and City Council approval for the City to request
consideration for Federal Emergency Relief Funding to complete permanent repair work
for the University Avenue Embankment Failure project.
(iJj ,:;fJti ~
Mict~ael C. Van Milligen
MCVM/jh
Attachment
cc: Barry Lindahl, Corporation Counsel
Cindy Steinhauser, Assistant City Manager
Gus Psihoyos, City Engineer
i, ~
.
DU~~E
~Yk.~
City of Dubuque
50. W. 13th Street
Dubuque, IA 52001
(563) 589-4270
(563) 589-4205 FAX
January 9, 2006
Mr. LeRoy Bergmann
Secondary Roads Engineer
Iowa Department of Transportation
Office of Local Systems
800 Lincoln Way
Ames, Iowa 50010
Phone:
Fax:
515.239.1528
515.239.1966
RE: ER Project No. ER - 2100 (636) -- 58 - 31
University Avenue Embankment Failure
ER Funding - Betterment Cost Justification
Dear Mr. Bergmann:
The City of Dubuque has submitted a Detailed Damage Inspection Report (RRW-31-01)
and requested consideration and approval for Federal Emergency Relief (ER) Funding
to complete permanent repair work for the above referenced project site.
The following supplemental information is provided for your review and demonstrates
justification that it would be beneficial for the FHWA to authorize the expenditure of ER
Betterment Funds for the permanent repair of the University Avenue Embankment
Failure site to prevent the potential future damages from another flood event.
DAMAGE SUMMARY
Since the damages to University Avenue occurred on a minor arterial as per the Federal
Functional Classification System map for Dubuque, repairs are not FEMA eligible, thus
the City is requesting that the site be considered for Federal ER Funding eligibility.
The site is located in the 3300 block of University Avenue. On May 22, 2004 heavy rains
resulted in a flooding event that adversely affected approximately 500 feet of
embankment on the north side of University Avenue. The existing creek located along
the bottom of the slope became flooded and caused the toe of the slope to erode and
scour, which caused the embankment slope to fail. The failed slope is in a near vertical
position that has encroached within approximately four feet of the existing curb line at
several locations and has undermined a section of the adjacent supported roadway.
Within the road right-of-way there are several existing underground and overhead
utilities in the immediate area of the embankment failure. These utilities are main
service lines for much of the west end of Dubuque. The owners of the utilities expressed
concern that it is not possible to temporarily relocate these service lines.
Should future rain events result in similar flooding, further erosion and scour may occur
which could cause damage to extend to the existing roadway and severely damage the
existing utilities.
SITE HISTORY
As a result from the May 1999 flood event, prior damage had occurred along an
approximate 100-foot section of the northerly side of the 3300 block of University
Avenue. In December 1999, a temporary pile-bracing wall was constructed within City
right-of-way to prevent further undermining of the roadway and to protect the existing
overhead and underground utilities in the area. No permanent repairs were performed.
This event, in May, 2004 resulted in an additional 350 feet of the embankment
experiencing damage to some degree.
COST ESTIMATES
The following cost information is provided to show that it would be beneficial for FHWA
to spend betterment funds to prevent the potential future damages from another ER
event. All the information and documentation used to calculate the costs is contained
within the project file kept at the City of Dubuque Engineering Office and is available for
review by FHWA.
COST TO RESTORE TO PRE-FLOOD CONDITION
The proposed construction would be to restore the existing embankment to a 1: 1 slope
and armor the bank with revetment. This is not considered to be a permanent solution
due to the potential for the toe of the slope to continue to erode and the potential slope
failure which would occur due to the unstable 1: 1 slope. Should future rain events result
in similar flooding and scour, the potential slope failure plane could cause damage to
extend under the existing roadway and severely damaging the City watermain and other
existing utilities.
The embankment failure section is approximately 500 feet long with variable widths and
depths. The depth of the failure varies from approximately 30 feet to 6 feet. To
reconstruct the slope and armor the bank with riprap resulting in a 1:1 slope would
restore the embankment to a pre-flood condition. The existing slope was heavily
vegetated which reinforced the embankment soils and held the steep slope in place.
The construction to restore the pre-existing 1: 1 embankment would incorporate the
placement of stabilization stone and riprap along the toe of the slope since it is not
possible to recreate the vegetative root structure which previously stabilized the
embankment.
In addition there is approximately 150 feet of PC curb and gutter and 200 feet of w-
beam guardrail damaged due to undermining of the roadway. In order to place the
embankment material and revetment an additional 350 feet of PC curb and gutter and
300 feet of w-beam guardrail will need to be removed and replaced to facilitate top side
construction. With the removal of the curb and gutter a 500 feet by 2 feet section of
HMA patch will be necessary.
To fill in the eroded area within the right of way, to protect with riprap, and repair
damaged roadway, would cost approximately $156,100. Some of this repair will be to an
area that was damaged prior to May 22, 2004. This proposed repair may not prevent
future mitigation of the creek towards University Avenue.
I Description of Work
I Quantity I Unit Cost I
Cost
Earthwork, Embankment-In-Place 4,000 CY $ 15.50 $ 62,000
Engineering Fabric 1,500 SY $ 2.25 3,375
Revetment, Class E 1,200 Tons $ 18.00 21,600
Curb & Gutter, P.C. Concrete, Per Plan 500 LF $ 14.00 7,000
Guardrail, Removal and Replace 500 LF $ 7.75 3,875
Roadway Pavement, HMA Patch 75 Tons $ 90.00 6,750
Traffic Control Lump Sum $ 7,500 7,500
Erosion Control Lump sum $ 15,000 15,000
Mobilization Lump sum $ 9,000 9,000
Right-of-Way Acquisition Lump sum $ 20,000 20,000
I RESTORE TO PRE-FLOOD CONDITION - TOTAL:
POTENTIAL RISK TO THE ER PROGRAM
$156,100 I
There are two known major slope failures in this area - in the years 1999 and 2004.
The damage to be repaired in both years was similar in extent. The estimated cost for
restoration for the 2004 event is approximately $156,100. If a 5 year cycle of failure and
the 2004 restoration cost estimate is assumed, the cost of restoration in a 15 year
period is $468,300. Potentially, the ER program has a $468,300 risk exposure over the
next fifteen years.
PROPOSED BETTERMENT JUSTIFICATION
Heavy rains similar to those of May 22, 2004 could result in additional damage to the
existing roadway and utilities. Due to the high average traffic volumes on University
Avenue and the proximity of the many utilities to the embankment it is necessary to
determine a method to protect the area with a permanent type repair. Two alternates
were investigated in evaluation of a proposed betterment. Repair Alternate No. 1
considered relocation of the existing stream to accommodate the construction of a 2.5:1
armored slope. This alternate will require right-of-way acquisition from the abutting
property owner and an individual permit from the Army Corps of Engineers (COE). The
City retained the Office of the State Archaeologist to complete a Cultural Resources
Evaluation of the impacted area. The determination has been made that there are no
items of archeological significance within the proposed project corridor. The City has
already contacted the COE and based on the findings of the Cultural Resources
Evaluation, preliminary indications are that the COE does not anticipate significant
issues through the permit process.
The second Repair Alternate NO.2 does not relocate the stream or require an individual
permit from the COE, instead a soldier pile retaining wall is constructed along the
embankment toe of slope and the existing stream, thus minimizing the impacted area.
REPAIR ALTERNATE NO.1
RELOCATION OF STREAM TO ACCOMIDATE A 2.5: 1 SLOPE
Repair Alternate No. 1 proposes to move and realign the existing stream away from the
existing embankment toe of slope creating a more stable 2.5 : 1 slope, and placing
stabilization stone and riprap on the embankment slope which will reinforce and prevent
future erosion and scour. As a result of moving the stream bed, an existing sanitary
sewer located along the bottom of the existing slope will require approximately 450 feet
of sanitary sewer to be relocated. Approximately 500 feet of guardrail will have to
removed and reinstalled and there will be 500 feet of curb and gutter that will need to be
replaced. Upon completion of the embankment repair, it is anticipated that
approximately a 500 feet by 2 feet section of HMA roadway patch will be necessary to
repair the northerly edge of pavement.
Repair Alternate No. 1 will require a permanent construction I maintenance easement or
right-of-way acquisition from the abutting land owner. City staff has met with the
property owner and obtained a preliminary verbal agreement for a permanent
construction easement to gain access to the abutting property to complete the repairs.
However, if negotiations are unsuccessful, eminent domain procedures may be
required.
I Description of Work Quantity I Unit Cost I Cost
Earthwork, Embankment-In-Place 4,500 CY $ 15.50 $ 69,750
Excavation, Class 13 2,100CY $ 8.00 16,800
Clearing and Grubbing Lump Sum $ 15,400 15,400
Engineering Fabric 1,500 SY $ 2.25 3,375
Revetment, Class E 1,650 Tons $ 18.00 29,700
Curb & Gutter, P.C. Concrete, Per Plan 500 LF $ 14.00 7,000
Guardrail, Removal and Replace 500 LF $ 7.75 3,875
Roadway Pavement, HMA Patch 75 Tons $ 90.00 6,750
Sanitary Sewer Relocate w/Utility Access 450 LF $ 195.00 87,750
Seeding, Fertilizing, Mulch 2,800 SY $ 6.75 18,900
Topsoil, Furnish and Place 2,800 SY $ 8.75 24,500
Traffic Control Lump Sum $ 7,500 7,500
Erosion Control Lump sum $ 15,000 15,000
Mobilization Lump sum $ 9,000 9,000
Right-of-Way Acquisition Lump sum $ 25,000 25,000
I ALTERNATE NO.1-TOTAL:
I $ 340.300 I
REPAIR ALTERNATE NO.2
CONSTRUCTION OF A SOLDIER PILE RETAINING WALL AT THE TOE OF SLOPE
Repair Alternate NO.2 considers the construction of a soldier pile retaining wall adjacent
to the embankment toe of slope and the existing stream and would not require stream
relocation or an individual permit from the COE. The wall initially investigated would
require drilling sockets into the existing rock below the normal channel streambed and
then placing HP 12x53 at 8'-4" on center into the socket, then installing precast concrete
panels or planks between the soldier piles. The total length of the wall would be
approximately 375 feet and the wall height examined will allow for a minimum 3:1 slope
from the guard rail to the top of the wall. Due to the presence of existing overhead
power lines and the vertical distance between the roadway and the existing stream bed,
it does not appear that top side construction will be an option and that construction of
the soldier pile retaining wall will occur along the bottom of the embankment slope. As a
result, it is anticipated that less roadway curb and guardrail will be impacted and only
150 feet of curb and gutter and 200 feet of w-beam guardrail damaged due to
undermining of the pavement will need to be replaced and reinstalled. Upon completion
of the embankment repair, it is anticipated that approximately a 200 feet by 2 feet
section of HMA roadway patch will be necessary to repair the northerly edge of
pavement. Scouring during future events would be prevented by placing revetment at
the toe of the wall and keying the soldier pile into the bedrock.
Repair Alternate No. 2 will also require a permanent construction I maintenance
easement or right-of-way acquisition from the abutting land owner.
I Description of Work
I Quantity I Unit Cost I
Cost
Earthwork, Embankment-In-Place 3,500 CY $ 15.00 $ 54,250
Clearing and Grubbing Lump Sum $ 15,400 15,400
Excavation, Class 13, Channel 475 CY $ 20.00 9,500
Soldier Pile Wall System, Furnish & Install 375 LF $ 1275.00 478,125
45-HP12x53 with Precast Concrete Panels
Revetment, Class E 150 Tons $ 18.00 2,700
Curb & Gutter, P.C. Concrete, Per Plan 200 LF $ 14.00 2,800
Roadway Pavement, HMA Patch 25 Tons $ 90.00 2,250
Guardrail, Removal and Replace 200 LF $ 7.75 1,550
Engineering Fabric 400 SY $ 2.25 900
Topsoil, Furnish and Place 700 SY $ 8.75 6,125
Seeding, Fertilizing, Mulch 2,000 SY $ 6.75 13,500
Traffic Control Lump Sum $ 7,500 7,500
Erosion Control Lump sum $ 15,000 15,000
Mobilization Lump sum $ 15,000 15,000
Right-of-Way Acquisition Lump sum $ 15,000 15,000
I ALTERNATE NO.2 - TOTAL:
I $ 639.600 I
. '.
BETTERMENT JUSTIFICATION
The proposed betterment (Repair Alternate No.1) will require fewer funds than the
future risk to the ER Program and demonstrates justification that it would be beneficial
for the FHWA to authorize the expenditure of ER Betterment Funds for the permanent
repair of the University Avenue Embankment Failure site to prevent the potential future
damages from another flood event. Repair Alternate No.2, although it reduces the
impact on the existing channel, has a greater cost than the Repair Alternate No. 1
option.
As a result of the pre-existing condition and the previously sustained damage in May
1999, the City, Iowa DOT and FHWA staff agreed that the prior embankment failure
area would not be eligible for ER funding and that only 80% of the estimate of probable
cost would be considered eligible. Based on the cost for Repair Alternate No.1, the
eligible cost for ER funding is as follows:
Repair Alternate No. 1 - Cost Estimate =
Eligible Cost - Adjusted =
$340,300
80% x $340,300 = $272,240
80% x $272,240 = $217,792
20% x $272,240 = $ 54,448
ER Funding Request
City Cost Share
=
=
Should you have any questions or need additional information, please contact me at
563/589-4270.
Sincerely,
wSW
Robert D. Schiesl, P.E.
Assistant City Engineer
City of Dubuque
Enclosure
cc: Michael Van Milligen, City Manager
Cindy Steinhauser, Assistant City Manager
Gus Psihoyos, City Engineer
Roger R. Walton, P.E., District Engineer
Ken Vanna, P.E., Local Systems Engineer
Max Grogg, PE, FHWA - Iowa Division