Agenda - Council - 08/08/2016 - Laserfiche WebLink

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Based on existing conditions,MnDOT State Aid operations Chapter 8820, Section 9936,requires the following minimum design standards for these street segments. . 12' drive lanes •2' curb reaction • 8' - 10' parking lanes* * Parking is allowed on MSAS streets when posted speeds are 45 mph or less. The pavement sections on both streets are generally in poor condition with the surfaces exhibiting numerous types of deformation. The pavement on Alpine Drive is exhibiting significant"tenting"along the frequent transverse cracks(extending across the street,perpendicular to the lanes),particularly in winter months when the ground is frozen. This results in extensive heaving of the pavement surface along the transverse cracks, often on the order of several inches,which can be extremely uncomfortable for drivers and is more importantly a safety issue due to the frequency of tires not being in contact with the surface of the street. While this street is only 15 years old,the extent of the tenting that occurs in winter months is such that staff feels this is a significant enough safety issue to warrant reconstruction. Soil borings will be completed as part of the Feasibility Report. This will allow staff to evaluate whether subgrade soil corrections will be required as part of this project,similar to the Garnet Street reconstruction project. The soil borings will also reveal the elevation of the groundwater table to determine whether dewatering operations will be required for any of the proposed improvements. The pavement on Sunwood Drive is exhibiting numerous types of cracking including alligator,block,transverse and longitudinal cracking. The alligator cracking is occurring in numerous areas,particularly east of Jaspar Street. Overlaying streets with significant alligator and block cracking is typically not effective or recommended because cracking typically reflects through new overlay pavement sections within several years. While this is typically is not an issue with infrequent transverse and longitudinal cracking due to the fairly wide spacing of the cracks, it becomes a bigger issue when alligator and block cracking are present in the existing pavement due to the close proximity of these types of cracks. Taking soil borings in areas where alligator cracking exists will allow staff to evaluate whether subgrade soil corrections will be required as part of this project, similar to the Garnet Street reconstruction project. The soil borings will also reveal the elevation of the groundwater table to determine whether dewatering operations will be required for any of the proposed improvements. At this time, Staff is confident that entire segment of Alpine Drive between Armstrong Boulevard/CSAH 83 to Variolite Street requires reconstruction. However, Staff is not as confident as to whether the entire segment of Sunwood Drive between Ramsey Boulevard/CSAH 56 and Bunker Lake Boulevard/CR 116 requires a full reconstruction,or whether one or more portions could receive mill and overlay improvements instead. This will be fully evaluated during preparation of the Feasibility Report. Off-street pedestrian facilities exist along both corridors.Alpine Drive has an off-street bituminous trail along the south side of the street,and Sunwood Drive has an off-street bituminous trail along the north side. The existing trails will not be evaluated as part of the Feasibility Report since they are being evaluated as part of the Trail Maintenance Policy that Staff is currently developing. This will allow Staff to evaluate all of the City's trails systematically to ensure that the proper trails will be maintained at the proper time. Storm sewer exists along both street corridors and will need to be evaluated as part of preparing the Feasibility Report. Public water supply and sanitary sewer utilities exist along the Sunwood Drive corridor,but not along the Alpine Drive corridor. These systems will also be evaluated as part of preparing the Feasibility Report regarding the need to repair or replace any of the existing utilities. Proposed Improvements— Due to the poor condition of the pavement sections,both segments are currently proposed to be reconstructed in 2017. The reconstruction of this segment of Alpine Drive is included in the City's adopted Capital Improvement