2007/11/21 Council Agenda Packet

r V Two pipelines under Chestnut Street will be subject to the fill loads. They are 48- and 72-1nch diameter parallel farce stain sewer pipelines. Chestnut Street is a south -north -oriented road that is Parallel to the west bank- of the Snohomish River, and extends from 36"' Street at its south end to Pacific Avenue at its north end. A BNSF track is located between Chestnut Street and the river. "I'hrce pipelines under 36"' Street at Chestnut Street %vill be subject to the fill loads. They are 60-, 36- and 30 -inch diameter parallel torce main sewer pipelines. In Phase I it was tound that the 60 - and 36- inch pipelines at another 36"' Street location would not be impacted by a BNSF rail track so they will not be evaluated in Phase 4. The 30 -inch pipeline will be evaluated in Phase 4. lnlorination (.)it the pipelines that is currently known to URS is as follows: • 72 -inch Pipeline under Chestnut Street: Based on the information provided by the City and from Sheets CA to C81 G32 and G35 of Brown and Caldwell 1995 "Snohomish River CSO (nterceptor - drawings, the 72 -inch pipeline along Chestnut street has the following features: I _ Type - Class V 72 -inch reinforced concrete cylinder ?. Wall thickness - 6 inches (off Sheet G32) or 7.75 inches (if Class V) 3. pipe designation - SM L2995 Gq A (provided by the City) 4. I, stirnated soil cover - 5 to 12 feet S. Pipe invert - approximately EI. 1.5 6. Pipeline support -- wood pile pair units at 12 -toot spacing 7. Pile unit capacity - 40 -ton piles for total capacity of 80 tons S. Installation date - 1995 • 48 -inch Pipeline under Chestnut Street: The 48 -inch pipeline is shown on the --South End Interceptor" 1982 Cl -42M Hill design drawings and the 1983 Arneron product detail drawings. Based on the information from the City, Ameron Sheets J -I to J-3. and CH2M Hill Sheets 2, 6, 7. and S. the 48 -inch pipeline along Chestnut Street has the followin1, features: 1 . Type — PC -100 48 -inch pre -stressed cylinder concrete, single waq).. 2. Nall thickness — 5 inches 3. Design eriteria 144ciot cover and 54 psi internal pressure 4. Pipe designation: SML2995 Q03 (provided by the City) 5. Estimated soil cover - 10 to 15 feet. 6. Pipe invert - approximately Ll. -2.5 7. Installation date - 1983 • 30 -inch Pipeline under 36"' Street: Based on Sheet C3 of the Brown and Caldwell 1995 drawings for the '- Snohonlish River CSU Interceptor" and Sheet 33 of the CH2M E{ill 1983 drawings for the -'Southwest Interceptor". the 30 -inch pipeline has the following features: URS 1 . -Type - 30 -inch reinforced concrete cylinder 2. Wall thickness -- no shown on available drawings 3. Pipe designation: SML2995 014 (Provided by the City) 4. Soil cover - 10 to 15 feet. 5. Pipe invert - approximately El. -2.5 6. Installation date — 1984 (City work order number 1 577) 102 Page 7 of 10 1L L