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and proximity to tree roots and its expansion potential, consolidation settlement potential, and subgrade conditions near storm drain crossings, etc. BSK Associates will then evaluate their findings and perform a geotechnical engineering analysis to develop conclusions and recommendations for the anticipated improvements. Consultant Selection BSK Associates was selected as part of the City's on-call consultant selection process. Following the preliminary study, City staff worked with BSK Associates to develop a detailed scope of work. City staff has reviewed and evaluated the proposal and verified that previous work performed by BSK Associates was satisfactory and recommends the award of the design contract to BSK Associates. The proposal outlined a geotechnical investigation on West Las Positas Boulevard, from 1-680 to the west and Santa Rita Road to the east, for a not-to-exceed amount of $234,784.45. The investigation of roadway from 1-680 to Hopyard Road and from Stoneridge Drive to Santa Rita Road are listed as optional tasks No. 6 and No. 7 in the proposal for a cost of$57,000 and $33,000, respectively. Staff recommends that the primary study section from Hopyard Road to Stoneridge Drive, which includes a post- report consultation, is authorized to BSK Associates as the first order of work for a not- to-exceed amount of$144,200. This will study the areas with the most distress, covering all possible forms of failure. The optional tasks No. 6 and No. 7 for the additional sections will be authorized by City staff, if necessary, based on the results from the primary study. Long Term Roadway Repair Solution It is anticipated that the long-term repair will require the entire roadway section, including the subgrade, to be removed, perhaps up to 4 feet below the base, and be replaced with an engineered roadway fill material. The road base and asphalt layers will then be installed over the engineered fill. The roadway will then "bridge" over the deeper clay soils which should maintain relatively consistent moisture content and not experience the same differential settlements that are currently observed. This will most likely require all existing curb and gutters, landscaping, and adjacent sidewalks to be removed and replaced in the settled areas. The permanent repair and reconstruction will incorporate the recommended bike and pedestrian improvements currently under development by the Traffic Division. It is anticipated that some of the utilities will require repair and replacement to address possible settled locations as the roadway is reconstructed. As part of the study phase, a detailed condition assessment of the utilities will be completed to ensure that they will not require replacement soon after the roadway reconstruction, as excavations for the repair of utilities may impact the engineered fill section. The utility investigation will be completed under the on-call contracts for CCTV through the Utilities Division. The roadway repair strategy selected will be prescriptive on how to backfill the utility excavations that will eventually occur in the future. The roadway reconstruction costs will not be fully known until the repair strategy is selected and the final roadway cross-section is identified. However, West Las Positas Boulevard, from Hopyard Road to Stoneridge Drive, is approximately 6,000 feet in length, with a paved roadway surface of approximately 470,000 square feet. Conventional pavement reconstruction runs between $8 to $10 per square foot, and it is Page 4 of 5