2802 HOYT AVE EVERETT ELKS Geotech Report 2018-01-02 MF Import

GeotechnicahEngineering Evaluation Everett Elks Club November 7, 2006 NGA File No. 751106 Page 6 We recommend that the adjacent structure and sidewalks be monitored for any distress that may result from the excavation and construction operations on this site. The monitoring program could include visually surveying the existing structures both prior to and during construction, and also by measuring elevations of strategic points on these structures. This can be better evaluated at the start of construction. A sky bridge is planned to be constructed across Hoyt Avenue from an existing parking garage to an upper floor on the eastern side of the new building. Supports for the bridge will be founded in the sidewalk areas oil the eastern and western sides of Hoyt Avenue. This is further discussed in the Foundations subsection of this report. The soils that are expected to be encountered during site development are considered moisture -sensitive and can disturb in wet conditions. We recomiend that the site be developed during the dry season. if construction takes place during the wet season, additional expenses and delays should be expected. Additional expenses could include the need for additional excavations and the need for placing a blanket of rock spalls on exposed subgrades and construction traffic areas prior to placing structural fill. Also, in wet weather, all-weather material may need to be used for structural fill and groundwater may need to be controlled. Erosion Control Measures The erosion hazard for the on -site soils is considered slight, but will be dependent on how the site is graded and how water is allowed to concentrate. Best Management Practices (BMPs) should Ua used to control erosion. Areas disturbed during construction should be protected from erosion. Measures taken may include diverting surface water away from the exposed areas and incorporating temporary sediment control measures before pumping runoff into the existing storm system. Temporary Slopes Temporary cuts will be needed for the construction of the underground parking garage. Temporary, unshored cut slope stability is a function of many factors, including the type and consistency of the exposed soils, depth of the cut, surcharge loads adjacent to the excavation, length of time a cut remains open, and the presence of surface or groundwater. it is exceedingly difficult under these variable conditions to estimate a stable, temporary, cut slope angle. Therefore, it should be the responsibility of tiie contractor to maintain safe slope configurations since he is continuously at the job site, able to observe NELSON GEOTECHNICAL ASSOCIATES, INC.