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Jenifer Willer - <br />! <br />September _10, 2005 ; <br />Page <br />The City is planning to retain an engineering geologist to conduct a .Level investigation of the depth to <br />rock rock digability and groundwater conditions; for design of the underground utility trench work: This <br />-investigation will include a number of 10 to 15 ft deep borings spaced throughout the project. <br />Soils data from the Lane County Soil Survey mapping indicates that the soli profile to 5 ft below ground <br />surface (bgs) generally consists of low to - medium plastic silty CLAY (CL). between the. surface and 6 to <br />12 inches bgs over highly plastic CLAY (CH)'that extends down to weathered be at depths varying <br />from 14 inches to 42 inches bgs. <br />Services Provided by the' City <br />We have assume that the will provY e: t - e o owing in ormation far the design analysis: <br />■ traffic volume counts classified by truck axle category-and estimates of traffic growth rate during <br />the design period <br />■ weekly bus volumes for each route on the prof ect segments <br />■ base maps of the street segments with the basis for the project stationing <br />Proposed work Scope <br />Project Reconnaissance <br />The project engineer will inspect . the streets to become familiar with site and pavement • conditions and to <br />.refine the testing : program . ; <br />-Non-destructive Deflection . T'esting <br />N6117 destructive ' deflection testing will be conducted .using . our .. KUAB.- Failing - • weight Deflectometer. <br />: (FWD), which • fully complies with ASTM D4694 and ' is annually reference calibrated at the FHWA <br />Western 'Regional FWD calibration center (current reference calibration conducted 1 0109107). The. testing. <br />will be accomplished in accordance with ASTM D4695 Level -2 at 200 -ft intervals in, the outer., wheel <br />paths of both lanes with 100 ft of stagger in the .testing interva.t between - lanes. The tests will - be <br />conducted during the, normal workweek between' -the hours. of 9 AM and • 4 PM. -One day of testing : is.... <br />planned and we will provide traffic control consisting of signing and flaggers to direct traffic around the <br />.testing operation. The in -situ resilient modulus (Mr) of. the subgrade •soil at the FWD- test locations. will <br />'be backcalculated using our PAVBACK '- software that directly takes. into account the - effects. of a' rigid <br />layer, e.g. bedrock, at shallow depth or non- linear, stress - - softening soil behavior. <br />Pavement Boring .explorations <br />Pavement core and boring explorations will be conducted to a .maximum depth of 5 ft or to, bedrock *f <br />encountered at less • than 5 ft- bgs. one day . of borings , at up . to 8 locations - is planned. The exploration <br />r <br />locations, will be selected - from review ' of the backcalculated M • values and - coordinated with the <br />exploration locations .of the City's engineering - geologist to, avoid duplication. ; <br />Drilling through the bound pavement layers will be conducted by diamond bit. core drill. Dri Ming below <br />. bound. layers will be conducted by solid stem :auger operated by our subcontractor, custom Hole . DrilTing. <br />The work • will. be directed by our- technician who will log . and classify the pavement layers and subgrade <br />soil. Bulk samples of Pavement and subgrade materials will .be' collected far laboratory. testing. Sufficient <br />samples: of subgrade soil and base materials also will be•' collected in case: laboratory testing ' f in place <br />recycling is later authorized. <br />The explorations will be conducted during_ the normal workweek between the hours of 9 AM and 4 PM. <br />We will provide traffic - control consisting of signing and flaggers to direct traffic around our work areas. <br />