3214 BROADWAY SEPA 017 - 004 Geotech Report 2025-04-14

American Property DeveloF.,,ient ES-0599.05 January 16, 2015 Page 4 Updated January 22, 2015 Everett's municipal code designates slopes of forty percent or greater, landslide hazard areas, seismic hazard areas and erosion hazard areas to be geological hazardous areas. Wetlands, flood plains and known erosion sensitive areas are listed as sensitive environmental features. A review of the Everett Department of Public Works and Planning (DPWP) records did not uncover any documentation indicating the subject property (or adjacent properties) possess geological hazardous areas or sensitive environmental features. Nor did interviews with departmental personnel reveal any oral record or known history of geologically hazardous activities or environmental sensitive features in the subject property's vicinity. Furthermore, ESNW has researched the subject's property's history back to 1894 and did not uncover any incidents indicating a geological hazard impacting the subject property. Based on our review of the available resources, the subject site is not located within any DPWP designated geologically hazardous areas or environmentally sensitive features. DISCUSSION AND RECOMMENDATIONS General Based on the results of our study, construction of the proposed assisted living facility at the subject site is feasible from a geotechnical standpoint. The primary geotechnical considerations associated with the proposed development include temporary slope excavations, excavation support, and foundation support. Based on the results of our study, the proposed building structure can be supported on conventional spread and continuous footings bearing on competent, undisturbed native soil. Based on the proposed excavation, we anticipate competent native soils suitable for support of foundations will be exposed at the foundation subgrade elevation. Where loose or unsuitable soils are exposed at the foundation subgrade elevation, the soils should be overexcavated and replaced with a suitable crushed rock material in foundation areas. Where sufficient space is available, a portion of the lower level excavation may be completed using temporary open cut excavations. Temporary shoring or a combination of shoring and temporary slopes will be necessary where the building will be sited in close proximity to the property limits. In our opinion, where shoring is necessary, the use of a conventional cantilever or tieback shoring system is feasible for temporary support of excavations. In our opinion, soil nailing is also a feasible alternative for excavation shoring. For purposes of this study, recommendations for conventional shoring and soil nailing are provided. With respect to adjacent property surcharge loading on the shoring system, further assessment of adjacent building structures and foundation elevations relative to the shoring system and foundation walls will be needed, as appropriate, based on the final siting and design finish floor elevation of the building. For purposes of this study, we have provided preliminary surcharge values for design of temporary shoring and permanent foundations walls, as appropriate. As previously, discussed, localized zones of groundwater seepage could be encountered. As such, groundwater seepage could be encountered in the proposed excavation which is anticipated to be advanced to depths of approximately eighteen to twenty five feet below existing grades. The presence of groundwater seepage in deeper utility excavations should also be anticipated. Earth Solutions NW,LLC