900 PACIFIC AVE WOMEN AND CHILDREN PAVILLION 2018-01-02 MF Import

i i I Providence Family Services Center 9-91M-�2�z3-0 August25, 1999 Page10 � � 6.0 CONCLUSIONS AND RECOMMENDATIONS Development plans call far construction of a new four- or five-story at-grade building, with the � possible addition of one or two future stories. We offer the following general geotechnical � conGusions and recommendations conceming this project. I • Feasi ili : Based on our field explorations,research, and analyses,the proposed building appears feasible from a geotechnical standpoint, contingent on proper design, layout, and construction. ! • Foundation Ontions: On our opinion, shallow spread fooGngs are not generaily suitable for supporting the proposed structure,due to the variable thidcness of loose i to medium-dense fill and native soils. For the northwestem portion of the building, ! we recommend the use of a pile or pier foundation extending downward to the very dense glacial till deposit, which lies at depths ranging up to 30 feet below existing i grades. However, spread footings appear feasible for the southeastem portion of the building, where the glacial till horizon is less than about 5 feet deep. Spread footings aiso might be feasible for other portions if a basement is included beiow the Ibuilding. • Floor Ontions: Soil conditions are not generally amenable to the use of a I soil-supported slab-on-grade fleor,due to the extreme variation in thickness of the loose to medium-dense soil deposits. To minimize settlements of the northwestem portion of the fioor, we recommend using a structurally supported floor, such as a post-tensioned concrete slab, reinforced concrete slab,orjoist-supported dedc. A soil-supported floor might be suitable for this portion if some settlements can be tolerated. The southeastem portion of the buildir.�footprint is better suited for use of a soil-supported slab-on-grade floor. • Retainina Wall O�tions: In our opinion, conventional backfilled, cast-in-place concretewallswillad� ;�atelysupportpartialbasementexcavations, loadingdodcs, utiliry vaults, and other below-grade features. These walls shouid be designed to � withstand appropriate lateral pressures. • Ravine Setbacks: The currently proposed building footprint lies approz,mately 100 fest horizontally from the existing ravine brink. In our opinion, based on our slope stability analysis, this distance constitutes a conservative se!back from the ravine;a lesser setback could be used For the building if desired,but we recommend that the final setback distance not be less than 50 feet. For pavements, utilities, luminaires, and other minor elements, we recommend maintaining a minimum setback of 15 feet from the brink; this would p;ovide adequate protection from a seismically induced slope failure, which our analysis indicated is most likely to � originate at a distance of about 10 to 12 feet from the brink. '' S\WORDPROC�59Vrolec15�5otCe�1100Gs1f712]RaCinsomPrm+CenceMmo�Rpl.wpE �17\ � �