05-26-2015 Council Minutes - Laserfiche WebLink

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MINUTES OF THE ORONO CITY COUNCIL MEETING Tuesday, May 26, 2015 7:80 o'clock p.m. PUBLIC WORKS DIRECTOR/CITY ENGINEER'S REPORT 9. BALDUR PARK ROAD DESIGN GUIDANCE Edwards stated the purpose of this action item is to gain Council approval of a design option for the Baldur Park Reconstruction Project. At the end of last year, beginning of this year, the Council was notified that FEMA fiwds were secured for a portion of this project. Approximately two months ago the Council authorized Bolton & Menk to compile some design options and testing. Edwards stated he would recommend Option No. 3, which is the partial depth reconstruction. David Martini, Consulting City Engineer, reminded the Council of the significant flooding experienced in this area last year. At the time the area was experiencing the flooding, discussions were held with the residents about the overall condition of the road. Since that time the residents have requested some improvements be made once the waters receded. Martini displayed the project area on the overhead. Martini indicated the yellow section is the area that was ultimately determined by FEMA to be necessary for some repair due to the flooding and that the FEMA money is earmarked for that area. The existing conditions of the road consist basically of two to three inches of bituminous, an average aggregate base thickness of 6 to 12 inches, and subgrade soils consisting of swamp deposits. Martini stated all of the options include maintaining the existing profile of the road and replacing the culvert crossings so that existing drainage patterns are maintained. No flood mitigation is recommended at this time since FEMA did not fund mitigation related improvements. Martini requested the City consider the following options: Option 1, is a full depth reconstruction. This option would consist of complete removal of the existing pavement structure along with removal of unstable materials below the subgrade. This option will require excavation to a depth of at least three feet with a width that extends at least three feet beyond the existing pavement edge on both sides of the road. The advantages of this option include the removal of potentially unstable subgrade materials, construction of a consistent pavement structure throughout the project area, and the life of the roadway would be longer compared to alternatives with a reduced scope of work. Some of the disadvantages of this option would be higher initial construction cost compared to alternatives with a reduces scope of work, poor drainage in this area will still be a factor which limits the life of the road, and the construction will require significant disruption to the adjacent properties. The total estimated cost is $413,780. The second option would be a full depth reclamation, which would consist of pulverizing the existing bituminous pavement along with a portion of the underlying aggregate base. A portion o the reclaimed material would be removed to maintain the existing grade of the road so that drainage patterns are maintained and the underlying subgrade materials are not surcharged by the additional weight of the road. Advantages of this option include a rehabilitated aggregate base and new pavement structure at a lower initial construction cost compared to full depth reconstruction and minimal disruption to adjacent properties during construction. Page 8 of 22