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City of Eugene Contract #2010-00218 <br />Exhibit B - Scope of Work <br />CONSULTING ENGINEERS FOR PAVEMENTS <br />PAVEMENT SERVICES, INC. 547 N.E. 20" AVENUE, SUITE 107 <br />PORTLAND, OREGON 97232-2862 <br />503.235.0377 • FAX 503.235.2885 <br />PSI@PSIPDX.COM <br />October 7, 2009 <br />j Jenifer Willer, PE <br />Eugene Public Works Engineering <br />99 E Broadway, Suite 400 - <br />Eugene, OR 97401 <br />Re: Patterson St -%E 13a' to E 19`h Pavement Design Proposal <br />Jenifer, <br />We are pleased to present the following proposal to provide pavement design recommendations for <br />rehabilitation of the above section of Patterson St. Our understanding of the project is described below <br />based on the information that you provided and our prior pavement design investigations for the <br />sections of Patterson from E Broadway to E 13d' and from E 196' to E 23rd. <br />Understanding of Project <br />The project section is a minor, arterial one-way, street with two travel lanes and parking lanes on each <br />side and' is approximately 2,400 ft long. It appears that the block from E 131 to E 141 has a composite <br />pavement (APC) section consisting of asphalt concrete (AC) on portland cement concrete (PCC). The <br />remainder of the project appears to have a conventional flexible pavement (ACP) section consisting of <br />AC on aggregate base (AB). <br />- <br />According to the Lane County Soil Survey maps, there are three soils units within the . project <br />consisting of the Malabon-Urban land complex (between 13' and 14d`), the Coburg-Urban land <br />complex (between 14d' and 16' Alley) and the Urban land-Hazelair-Dixonville complex (between 161 <br />Alley and 19'h). The soils in these units are' described as low to moderately plasticity SILT (ML) or <br />CLAY (CL) and by their description should be amenable to in-place cement treatment if necessary for <br />reconstruction. <br />The APC section that we encountered in our prior investigation north of 131 consisted of 4 to 5 inches <br />AC on 5 to 6 inches of PCC. If the APC in the project has a similar section and reconstruction is <br />necessary, in-place cement treatment of the subgrade soil would likely be preferable compared to <br />aeration and compaction of the subgrade or excavation and stabilization of the subgrade by aggregate <br />backfill. The ACP section that we encountered in our prior investigation south of 19' consisted of 6 to <br />7 inches of AC on 7 to 25 inches of AB. If the ACP in the project has a similar section and <br />reconstruction is necessary, in-place cement treatment of the existing AB would be preferable to avoid <br />re-working of the existing subgrade. Hence, our proposed work scope includes laboratory testing for <br />in-place cement stabilization of either subgrade soil or existing AB (but not both) if reconstruction is <br />necessary. <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 />■ weekly bus volumes for each route on the project segments <br />