2007/11/21 Council Agenda Packet

v For the geotecttnical drilling, the City painted the 48- and 72-1nch pipeline centerlines along 100 feet of' the road surface at the south end of Chestnut Street. URS measured the centerline of the 48 -inch pipeline to be about 8 feet east of the west edge of the road, and the centerline of the p- inch pipeline to be about 9 feet cast of the 48 -inch pipeline and 17 feet east of the west edge of the road. SCOPE OF WORK URS .vill complete the following four tasks for Phase 4: • Task 70100: Geotechnical Investigation • Task 70200: Pipeline Impact Evaluation • Task 70300: Pipeline Protection Options • Task 70400: Review Meetings • Task 70500: Technical Memorandum • Task 70600: Undefined Services For Phase 4. URS will maintain staffing continuity from the Phases 1, 2, and 3 of the project: • Cecil Urlich, P.E. - Project manager and Engineer of Record • \iangdong [-fail. Ph.D.. P.E. and Marty McCabe, Ph.D.; P.E. - Geotechnical engineentig • Enam Kazi, P. En��. and Vichai Vitsupakorn, P.E. — Structural en<gineerirrg • Richard Smith. C.E.T. —Cost estimating. Task 70100: Geotechnical Investigation: This geotechnical investigation includes field explorations, laboratory testing, and engineering analyses. Iwo borings (13-1 and Q-2) were completed on September 20, 2007 in order to expedite the work and take advantage of an available drill ng. The borings were completed near the south end of Chestnut Strcct and therefore only represent geotechnical conditions in the south end area. Tire focus Of the work was to investigate: • The existing pipelines and their supporting structure conditions • Soil and ground water conditions, including soil profile. • Other underground structures encountered, if any. The right-of-way and permits for the field work were obtained by the City. URS sub -contracted the drilling to Environmental Drilling Inc., of Snohomish. Dr. Han inspected the boring activities, collected samples, and prepared logs of soils encountered. Soil penetration tests were conducted at 5 -foot intervals of depth, and results were converted to equivalent standard penetration test (SPT) values. Relatively undisturbed samples were collected from soft soils using Shelby tubes. Field pocket penetration (PP) strength tests were completed on undisturbed cohesive soils. The borings show that the soils in the area consist of sandy gravel fill from 0 to 5 feet, peat with clay and silt from 5 to 20 feet. and medium dense sand below 20 feet. Groundwater was found at a depth of 8 feet. Therefore, the pipelines at the south end of the area appear to be buried in peat with the 48 -inch pipeline below water and the 72 -inch pipeline partly below water. All saved and labeled soil penetration test samples together with the Shelby tube samples were taken to the URS laboratory in Seattle for cliecking soil classifications and the following testing: URS 1�3 Page 8of10