DEPARTMENT: Transportation
FILE TYPE: Consent Action
TITLE
title
Authorization To Execute Third Contract Amendment With Alliant Engineering, Inc., For Professional Engineering Services For County Road Retaining Wall Assessments And Final Design Of County State Aid Highway 38 (McAndrews Road) Retaining Walls, County Project 97-218
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PURPOSE/ACTION REQUESTED
Authorize execution of the third contract amendment with Alliant Engineering, Inc. to complete additional engineering design services required to address newly identified site constraints, structural design complexities, and extended project coordination necessary for the successful delivery of County Project (CP) 97-218.
SUMMARY
Dakota County is advancing CP 97-218 to analyze, repair, and replace deteriorating retaining walls along County roadways to maintain safe and reliable infrastructure. Twenty-four retaining walls have been evaluated to determine condition, prioritize repairs, and support capital planning needs. Four priority walls along County State Aid Highway (CSAH) 38 were advanced into final design due to documented deterioration and the potential for impacts to roadways and bike/pedestrian facilities (Attachment: Location Map).
During design development, significant and unanticipated physical constraints were encountered, including extraordinary wall height, reduced construction areas, sightline limitations, and the need to avoid private property impacts. These conditions required substantial modification to the original scope, including extensive geotechnical review, specialized structural design, and multiple design iterations to ensure constructability within the County’s right of way.
As walls 11 and 14 presented more complex design challenges, the project team determined that separate plan sets would be required for walls 12/13 and walls 11/14. TKDA was added as a subconsultant to provide specialized structural engineering and quality control for these advanced design elements. These scope additions and extended coordination efforts now require a third contract amendment.
The negotiated additional cost is $105,670 (Attachment: Additional Tasks Estimate), bringing the amended contract amount to $508,993. The current engineer’s estimate for construction of the four walls is $10.6 million, placing the consultant design contract at 4.8 percent of anticipated construction costs-consistent with the typical range for projects of similar scale and complexity.
Need for Amendment
Additional work outside the original scope has been identified as necessary to complete project design:
• Project Management and Coordination. Extended design schedule, additional review cycles, and increased inter-disciplinary coordination due to evolving site constraints: $23,240.
• Final Construction Plan Preparation. Separation into two plan sets and specialized engineering for walls 11 and 14, including cast-in-place design solutions required to remain within the County right of way and resolve long-term sightline issues: $32,680.
• Specialized Geotechnical and Structural Analysis. Additional investigation and design necessitated by extraordinary wall heights, confined construction zones, and constructability limitations: $29,850.
• Subconsultant Quality Assurance/Quality Control Review. Additional technical review and engineering validation by TKDA to ensure the structural feasibility of wall types under consideration: $19,900.
These tasks are essential to deliver a complete, constructible, and safe final design.
RECOMMENDATION
recommendation
Staff recommends authorizing the third contract amendment with Alliant Engineering, Inc. for an amended contract value not to exceed $508,993.
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EXPLANATION OF FISCAL/FTE IMPACTS
The Transportation Capital Improvement Program includes $1.3 million for retaining wall repairs along the County’s roadway system. Sufficient funding is available to support this contract amendment.
CP 97-218 Countywide Retaining Wall Repair
|
Fund Source |
Total Approved Budget |
Total Available |
|
CSAH |
$1,331,678 |
$832,262 |
|
Total |
$1,331,678 |
$832,262 |
☐ None ☒ Current budget ☐ Other
☐ Amendment Requested ☐ New FTE(s) requested
RESOLUTION
body
WHEREAS, Dakota County is undertaking County Project (CP) 97-218 to evaluate, repair, and replace deteriorating retaining walls along the County roadway system; and
WHEREAS, four retaining walls along County State Aid Highway 38 have been identified as priority structures requiring full replacement or design solutions with equivalent service life; and
WHEREAS, the County Board previously executed Contract DCA20887 with Alliant Engineering, Inc. for engineering design services for CP 97-218, with subsequent amendments due to evolving project scope; and
WHEREAS, additional structural complexity, right of way limitations, sightline deficiencies, and constructability challenges have necessitated design modifications and specialized engineering not included in the original scope of work; and
WHEREAS, staff has negotiated the cost for the additional engineering services and determined the fee to be reasonable and consistent with industry standards; and
WHEREAS, sufficient funding exists within the adopted CP 97-218 budget to proceed with the requested amendment.
NOW, THEREFORE, BE IT RESOLVED, That the Dakota County Board of Commissioners hereby authorizes the Assistant County Manager: Physical Development to execute the third contract amendment with Alliant Engineering, Inc. in an amount not to exceed $508,993, subject to approval by the County Attorney’s Office as to form.
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PREVIOUS BOARD ACTION
23-427; 9/26/23
ATTACHMENTS
Attachment: Location Map of 4 Walls
Attachment: Additional Tasks Estimate
BOARD GOALS
☐ Thriving People ☐ A Healthy Environment with Quality Natural Resources
☒ A Successful Place for Business and Jobs ☐ Excellence in Public Service
CONTACT
Department Head: Erin Laberee
Author: Imran Ahmed