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<br /> ' Mat[ Rodrigues <br /> December 11, 2008 <br /> Page 2 <br /> 2-lane section to support partial depth reconstruction over the existing aggregate base while meeting the <br /> grade constraints imposed by the curbs, gutters and driveways. Due to the apparent need for <br /> reconstruction, we have included laboratory testing of bulk samples of subgrade soil from the core <br /> explorations in order to evaluate the feasibility of subgrade compaction and/or the need for subgrade <br /> stabilization to support the reconstruction work. <br /> Coburg Rd <br /> The road has a 5-lane section with moderate crown and continuous bike lanes on each side. The <br /> pavement in the outer lanes of both directions is in fait condition with isolated areas of medium <br /> severity alligator cracking and the pavement in the inner lanes of both directions is in fair to good <br /> condition with ,isolated areas of low severity cracking. Much of the cracking in both the inner and <br /> outer lanes appears to be "top-down" cracking. The section south of Frontier Dr appears to be in very <br /> good condition. The City's PMS records indicate that the road received a 2 inch overlay in 1998 north <br /> of Cal Young and in 2000 south of Cal Young. The PMS records also indicate that from [he north <br /> project limit to street number 470 (at approximately 1,860 fr north of the south limit of the project) the <br /> pavement section consists of 9 inches AC (including the recent 2 inch overlay) on 16 inches of AB. <br /> From street number 470 to the south limit of the project, the PMS records indicate that the pavement <br /> section consists of 10 inches of AC on unlrnown base. <br /> It appeazs likely that the pavement can be rehabilitated by inlay with possibly partial depth <br /> reconstruction in isolated areas. Overlay does not appear to be feasible due to the grade constraints <br /> imposed by the concrete islands, continuous curb and gutter and numerous driveways. <br /> W 13"' Ave <br /> The pavement between Adams and Jefferson appeazs to be in good condition with occasional low <br /> severity transverse cracking, longitudinal cracking and intermittent panel joint cracking. The pavement <br /> between Jefferson and Washington is in fair to poor condition with isolated aeeas of medium to high <br /> severity cracking that appears to be reflected from corner breaks, cracks and joints in underling PCC <br /> slabs. <br /> We investigated the section between Monroe and Willamette in 1991 and at that time the pavement <br /> consisted of 1.5 to 3 inches of AC on 6 to 7 inches of PCC. The pavement condition then was <br /> relatively poor with significant alligator cracking in the AC surface course and extensive reflective <br /> cracking of corner breaks, divided slabs and joint faulting from the underlying PCC. According to the <br /> City's PMS records, the section between Monroe and Washington received a 3 to 4 inch overlay in <br /> 1997, which appears to have performed very well over the past i l years based on the pavement's <br /> relatively good current condition. The PMS records indicate that the pavement in the section between <br /> Adams and Monroe also received a 3 inch overlay in 1997 and now consists of 10 inches of AC on AB <br /> of unknown thickness. <br /> Reconstruction will likely be required between Jefferson and Washington due to the distress caused by <br /> the underlying PCC pavement. Given the apparent good performance of the 3 to 4 inch overlay placed <br /> between Monroe and Jefferson in 1997, 3 to 4 inch inlay is a likely option to extend the life another l0 <br /> yrs., However, reconstruction would be necessary to provide a 20 yr life due to the potential of <br /> reflective cracking from the underlying PCC. The section between Monroe and Adams likely can be <br /> rehabilitated with inlay since the existing AC appears to be relatively thick based on the PMS records. <br /> Due to the apparent need for reconstruction between Jefferson and Washington and possible need for <br /> reconstruction between Washington and Monroe,'we have included laboratory testing of bulk samples <br /> of subgrade soil from the core explorations in order to evaluate the feasibility of subgrade compaction <br /> and/or the need for subgrade stabilization to supporrthe reconstruction work. <br /> Services Provided by the City <br /> We have assumed that the City will provide the following information for the design analysis: <br /> • traffic volume counts classified by truck axle category and estimates of traffic growth rate <br /> during the design period <br /> <br />