Agenda - Council - 08/08/2022 - Laserfiche WebLink

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Staff review of the geotechnical report found the majority of sub -base material to be poorly graded sand and poorly graded sand with silt, these materials are well suited for pavement support and are considered non -frost susceptible and are also free draining materials. An approximately 600-foot section of 167th Lane east of Armstrong Boulevard found undesirable materials in the top 3 feet of sub -base. These materials are proposed to be replaced with 2 feet of select granular material on top of geotechnical fabric. For the project east of Armstrong Boulevard, Staff if proposing to use the current standard City pavement section of 4 inches aggregate base, and 3.5 inches new bituminous pavement. The 4 inches of aggregate base is proposed to be composed of recycled reclamation material. For the project west of Armstrong Boulevard, Staff is proposing to use a modified reclamation rehabilitation. This will include reclamation of the existing bituminous and underlying aggregate base, removal of 2 inches reclamation material, and placement of 2 inches new bituminous pavement. This will leave 4 to 5 inches of reclamation material in -place as support for the new 2 inches of bituminous pavement. This method will remove the need to remove and replace driveway tie-ins, and greatly reduce the required boulevard restoration. This project proposes to add a half cul-de-sac to the dead end on 169th Avenue west of Rabbit Street. The half cul-de-sac can be constructed within the existing right-of-way on the south half of 169th Avenue. Extensive review found no right-of-way or roadway easements currently exist for the north half of 169th Avenue. Internal Staff discussions with public safety and public works support this proposed improvement. Any improvements beyond the existing roadway would require easements, and would have severe impacts on the property along the north side of 16h Avenue. The current swales along the streets are not proposed to be re -graded as part of this project beyond minor grading associated with replacing the street culverts, no issues with the drainage was discovered during project design. The existing metal culverts crossing the streets are proposed to be removed and replaced with concrete culverts. This is to ensure the culverts will last at least through the proposed 60-year design life of the fully reconstructed streets. Build Process .Install traffic control and erosion control measures o These are maintained throughout the project . Project removals (streets east of Armstrong Blvd) o Perform any subsoil corrections • Place new concrete curb and gutter (approx. 400-foot section of 167th Lane west of Armstrong Blvd) o Existing bituminous curbing will not hold up to reclamation process . Remove excess reclaim material, shape and compact remaining material o Remove approx. 1.5 inches on streets east of Armstrong Blvd 0 Remove 2 inches on streets west of Armstrong Blvd o Excess reclaim is stockpiled and will be used on future City projects • Place first lift of bituminous pavement on streets east of Armstrong Blvd • Finish driveway repairs . Restore the boulevard in any impacted areas 0 2 inches topsoil, seed and hydro -mulch o Due to project timing, dormant seeding may be required • Traffic Control devices are removed as the project allows • Place the final lift of bituminous pavement • Erosion control measures are removed after restoration has been completed Preliminary Schedule Remaining • Council Awards Contract to the lowest responsible bidder o August 8, 2022 • Contractor begins construction o August 2022 • Contractor Substantially Completes construction