4D, 2011 PMP Feasibility Report - Laserfiche WebLink

Home Browse Search

PROPOSED STI2EET IMPROVEMENTS Due to the existing conditions of the roadways as previously outlined and as shown in the soil borings, City staff recommends that all of the proposed roadways within the project be improved with a bituminous reclamation. Bituminous reclamation (or reclaim) involves grinding the existing asphalt surface and underlying aggregate base together, which creates a new uniform roadway base material. Some of the reclaimed material is then removed in order to meet the existing curb and gutter grades. Finally, the new base is graded and compacted in preparation for the new bituminous pavement. As shown on the soil borings, all of the existing roadways within the project have varyzng thicknesses of bituminous pavement and aggregate base. Refer to the Appendix for tl�e soil boring results. On average, the new section for all the roadways will have approximately Z- inches of reclaimed base material with 3.5-inches of new bituminous pavement. This recommended improvement will meet the City's minimum standard for a 7-ton design roadway, Projected PCI ratings for these roadways range from "problem" to "adequate." City staff has reviewed all of the streets and agree with the PCI ratings, with the exception of Colleeri Court which has an "adequate" PCI rating. This roadway has experienced an accelerated deterioration since 2008 and City staff recommends that Colleen Court be rated as "marginal." Roadways rated as "problem" would typically be considered for full street reconstruction. The "problem" roadways in the proposed project have curb lines that are generally in good condition. These roadways also have an existing aggregate base, and can be improved with a bituminous reclaim. However, these roadways may require additional subgrade corrections prior to bituminc�us paving. In the City's 2011-2015 Capital Improvement Plan, the improvement to Amble Road was proposed as a street reconstruction that includes the installation of concrete curb and gutter. Soil borings and a geotechnical analysis performed for this study indicate that the existing bituminous and aggregate base thicknesses for Amble Road would support bituminous reclamation as a viable improvement option for the roadway. Several Amble Road residents requested at the September 23, 2410 neighborhood meeting that Amble Road maintain its rural section and not include curb and gutter. At the October 11, 2010 Worksession, the City Council discussed the Amble Road resident feedback and technical analysis and directed staff to include Amble Road within the bituminous reclaim project. The new roadway will maintain its current 24-foc�t �idth and rural section. Refer to the Appendix for comments received from residents at the neighborhood meeting. All of the improved streets will maintain their existing widths and existing curb and gutter will only be removed and replaced where it is sunken or damaged. However, additional curb and gutter may need to be removed and replaced in areas where utility repairs are being proposed. By preserving the existing curb lines along the roadways, the new vertical alignments will matc�i ihe in-place alignments. Necessary corrections to the roadway subgrade will be made in �reas exhibiting more severe signs of distress prior to placing the bituminous pavement. G�