3301 SEAWAY BLVD Geotech Report 2022-10-25

January 13,2016 Project No. T-7342 With wall backfill placed and compacted as recommended, and drainage properly installed, we recommend designing unrestrained walls for an active earth pressure equivalent to a fluid weighing 35 pounds per cubic foot (pcf). For restrained walls, an additional uniform load of 100 psf should be added to the 35pcf. To account for typical traffic surcharge loading, the walls can be designed for an additional imaginary height of two feet(two- foot soil surcharge). For evaluation of wall performance under seismic loading, a uniform pressure equivalent to 8H psf, where H is the height of the below-grade portion of the wall should be applied in addition to the static lateral earth pressure. These values assume a horizontal backfill condition and that no other surcharge loading, sloping embankments, or adjacent buildings will act on the wall. If such conditions exist, then the imposed loading must be included in the wall design. Friction at the base of foundations and passive earth pressure will provide resistance to these lateral loads. Values for these parameters are provided in Section 4.5 of this report. 5.8 Site Walls Rockeries A rockery is not intended to function as an engineered structure to resist lateral earth pressure as a retaining wall is. The primary function of a rockery is to cover the exposed soil face to reduce the potential for erosion. All rockery construction should conform to the Associated Rockery Contractors (ARC) Standard Rock Wall Construction Guidelines. We recommend limiting cut rockeries to a height of ten feet when facing undisturbed dense native soils,and four feet where placed against unreinforced structural fill. Where buildings will be constructed above and adjacent to rockery construction,the foundations should be lowered to prevent surcharge loading on the rockery. Foundation depths should provide for a theoretical 1:1 influence line extending from the footing edge to pass beneath the rockery base. Where rockeries of four feet or less will be constructed against structural fill, the structural fill should be overbuilt and then cut back prior to constructing the rockery. This will provide a more competent and stable soil face behind the rockery. If rockeries placed against fill will be surcharged,and in those locations where rockeries against fill will be greater than four feet, the fill should be reinforced using a geogrid or geotextile material. A detail illustrating typical reinforced fill rockery construction utilizing geosynthetics is presented on Figure 5. Mechanically Stabilized Earth (MSE)Block Walls MSE Block retaining walls may be constructed in addition to or in lieu of rockeries. These retaining walls can be constructed using a segmental block product such as Keystone, Lock + Load, or Ultra Block. Typical MSE Block retaining wall construction details and notes are shown on Figure 4. Once the grading plan has been finalized,we can provide wall designs for project construction, if requested. Page No. 12