Consider City Council Recommendation to Accept Feasibility Report for 2020 Pavement Overlay Improvements, Improvement Project No. 20-02

Purpose:
The purpose of this case is to consider providing a City Council recommendation to accept the Feasibility Report for 2020 Pavement Overlay Improvements, Improvement Project No. 20-02.

Background:
Pavement and Surface Evaluation Rating (PASER) values are assigned annually to all public street segments. Street segments with a PASER value between 3 and 6 indicates the segments may be good candidates for overlays. Overlays are typically completed every 20 years on bituminous pavement sections, until such time that the street needs to be reconstructed.

Overlay improvements increase the structural capacity of the pavement section, and help prevent stormwater runoff from infiltrating into the underlying aggregate base and subgrade sections. Overlays are one tool the City uses to cost-effectively maintain streets over their serviceable life, which when properly constructed is anticipated to be 60 years.

Attached is a figure showing the street segments proposed to receive overlay improvements in 2020 per the 2020 – 2029 Capital Improvement Program (CIP). The streets are located in the following residential developments:

• Klemish and Flores
• Sunfish Square
• Sunfish Square 2nd Addition
• Windemere Woods
• Windemere Woods 2nd Addition

On December 10, 2019, the City Council ordered Staff to prepare a Feasibility Report to explore numerous aspects of the proposed improvements including whether they are feasible, necessary and cost-effective, whether they should be completed alone or in conjunction with other improvements, and to explore design options, if necessary. Estimated project costs and funding sources are also being explored in more detail than was done to develop the Capital Improvement Program (CIP). A preliminary project schedule is also being developed within the Feasibility Report.
 
(This paragraph was modified January 17th)  A copy of the draft Feasibility Report is attached.  In summary, the proposed improvements were not found to be feasible and cost-effective from an engineering standpoint, and Staff does not support construction of the 2020 bituminous overlays as identified within the current CIP. These streets would be most cost-effectively maintained by reconstructing them after such time as their PASER ratings fall to a rating of 3 or below. Instead, Staff recommends reviewing the current CIP to identify other street segments for 2020 mill and overlay improvements based on available funding, and authorizing Staff to prepare a new Feasibility Report for proposed 2020 mill and overlay improvements under City Improvement Project No. 20-02.

The proposed improvements are designated as City Improvement Project #20-02, 2020 Overlay Improvements.

Staff estimates 20 minutes will be required to present this case and respond to questions.

Observations:
No ground penetrating radar or pavement coring data existed for these streets and Staff had intended to complete field reviews and to research as-built plans and other documentation to determine if any of the street segments had degraded to the point that mill and overlay improvements were no longer feasible, meaning the street required reconstruction instead.
 
While reviewing as-built plans it was determined that the existing pavement sections were generally constructed with less than 3½ inches of pavement, which makes it difficult to complete mill and overlay improvements.  Staff therefore contacted WSB and Associates to order pavement corings along each street segment to verify pavement section thicknesses.  The corings revealed that the bituminous pavement sections generally varied between 2 and 3 inches.  This would make it difficult to complete a standard mill and overlay project. In addition, the corings revealed significant degradation of the pavement in most areas meaning the pavement structure was inadequate to support an overlay in most areas. Staff met with Mr. Thomas Wood from WSB on January 16th to discuss the pavement coring results and options for moving this project forward.  Three options were generally identified as being feasible.
 
The first option would be to repair damaged curb and gutter and complete a variable-depth mill and paving project in 2020 by milling all existing pavements to full depth, then leveling, shaping and compacting the underlying aggregate base, then paving all streets with about 2½ -inches of new bituminous pavement.  The cost for this option would be significantly more than a standard 2-inch mill and overlay, and the resulting anticipated pavement life would be roughly 25 years.
 
The second option would be to repair damaged curb and gutter and reconstruct the streets using a full-depth reclamation process in 2020.  Though the cost for this option would be significantly more than the first option, the resulting anticipated pavement life would be 60 years.
 
The third option would be to wait to reconstruct the streets until the end of the useful life of the pavement, which is estimated to be 5 to 10 years out.
 
(This paragraph was modified January 17th) Staff recommends the third option as noted in the draft Feasibility Report.  If the Feasibility Report is accepted as is, the City Council will be approving Staff’s recommendations to not mill and overlay the streets identified within the 2020 - 2029 CIP, but instead review the current CIP to identify other streets that are the best candidates for 2020 mill and overlay improvements based on available funding sources, and authorize Staff to prepare a new Feasibility Report for proposed 2020 mill and overlay improvements under City Improvement Project No. 20-02.

This winter and spring, Staff intends to review our current pavement rating system and processes for adding pavement management projects to the Capital Improvement Plan (CIP) to ensure that projects included in the CIP moving forward are identified accurately and can be constructed as proposed.

Before the pavement coring results were received and Staff was able to discuss the findings with Mr. Wood from WSB, notices were mailed to property owners having direct access to streets proposed to receive mill and overlay improvements inviting them to a public engagement workshop on Wednesday, January 22nd.  The purpose of the workshop was to explain the need for and scope of the proposed improvements, anticipated construction impacts, estimated costs, proposed funding program, and preliminary project schedule.  Based on the findings of the pavement corings and Staff’s discussions with Mr. Wood from WSB, a second letter was mailed to the same property owners on January 17th canceling the workshop for January 22nd.

Alternatives:
Alternative #1 – Motion to recommend City Council acceptance of the Feasibility Report for the 2020 Pavement Overlay Improvements, Improvement Project No. 20-02.

Alternative #2 – Motion of other.

The Feasibility Report was prepared in-house as part of Staff’s normal duties.

Staff recommends alternative #1.

Motion to recommend City Council acceptance of the Feasibility Report for the 2020 Pavement Overlay Improvements, Improvement Project No. 20-02.