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<br />May 21, 2015 <br /> <br />City of Orono <br />Attn: Adam Edwards <br />PO Box 66 <br />Orono, MN 55323 <br /> <br />RE: Baldur Park Road – Improvement Options <br /> <br />Dear Adam: <br /> <br />As authorized, American Engineering and Testing (AET) has provided the City with an evaluation of the <br />existing pavement and soil conditions for Baldur Park Road between North Shore Drive and its terminus <br />(approximately 1150 ft. to the northwest). AET’s report indicates the following existing conditions: <br /> <br />• Average bituminous thickness of 2” to 3” <br />• Average aggregate base Thickness of 6” to 12” <br />• Subgrade soils consisting of swamp deposits (peat) <br /> <br />Since the subgrade materials are highly compressible and frost susceptible, AET recommends a preferred <br />option that consists of removing the swamp deposits to a depth of 3’ below the subgrade and replacing the <br />material with suitable fill. The recommended pavement section would consist of sand, aggregate base <br />and new pavement. With the understanding that the City’s budget and/or other factors may limit the <br />amount of full depth reconstruction work that is practical in this area, full-depth reclamation has been <br />recommend by AET as a less desirable alternative. <br /> <br />Based on the evaluation and recommendations provided by AET, we recommend that the City consider <br />the following options. All of the options include maintaining the existing profile of the road and <br />replacing the culvert crossings so that existing drainage patterns are maintained. No flood mitigation is <br />recommended at this time since FEMA did not fund mitigation related improvements. <br /> <br />Full Depth Reconstruction <br />This option would consist of complete removal of the existing pavement structure along with removal of <br />unstable materials below the subgrade. This option will require excavation to a depth of at least 3’ with a <br />width that extends a least 3’ beyond the existing pavement edge on both sides of the road. The <br />recommended pavement structure is as follows: <br /> <br />• 3.5” of bituminous <br />• 6” of Class 5 aggregate base <br />• 12” of select granular material <br />• Geotextile fabric <br /> <br />The advantages of this option include the following: <br />• Removal of potentially unstable subgrade materials <br />• Construction of a consistent pavement structure throughout the project area <br />• The life of the roadway would be longer compared to alternatives with a reduced scope of work <br />Entire Council Packet 05/26/15 [Page 327 of 378]