7815 E GLEN DR 2016-01-01 MF Import

i 5.3 L�uefaction It is our opinion, that the risk of damage to the proposed structure by liquefacuon during a seisu�ic event is low due to the relatively dense state and coarse, granular nature of the bearing , sedimenu. 5.4 Ground Motion Based on the site stratigraphy and our visual reconnaissance of the site, it is our opinion that :uiy earthquake damage to the proposed savcture, when founded on a suitable bearing stratum in accerdance with the recommendations of this report, would be caused by the intensity and acceleration associated with the event and not any of the above discussed impacts. Structural design of the building should follow Uniform Building Code (UBC) standards for Seismic Zone 3 (Z factor = 0.3) (1997 UBC Table 16-n and a seismic ccefficient of 0.33 (1997 UBC Table 16-Q), corresponding to an S� soil type (1997 UBC Table 16-.n. 6.0 LANDSLIDE tiAZARDS AND MITIGATION As previously discussed, the portioa of the site in which the proposed duplex is to be located consists of an east-facin�• �:�pe. Slope gradients on the westem, upper portion of the slope range from approxima�ely 30 to 65 percent. During our reconnaissance of the property, we did not observe features indicative of significant earth movement such as tension cracks, soil slumps, or debris flows. To our knowledge, there is no history of landsliding in the vicinity of the properry. �� As previously discussed, natural soils underlying [he slope generaliy consist of inedium dense to very dense, lodgement till sediments overlain by uncontrolled fill and loose, organic topsoil or topsoil fill. We anticipate that much of the fill and loose surficial topsoil or topsoil fiU will be removed from the building area during construction. We recommend that these materials be disposed of off-site. Additionally, we anticipate that grading between the west side of the p:oposed duplex and East Glen Drive during construction of the proposed driveway will decrease the gradient of the steep portion of the slope in this area. Given the encountered subsurface conditioas and the performance of the exisdng slopes at the site, it our opinion that the risk of damage to the proposed structure and adjacent properties due to landslide hazards will be minimal, provided the recommendadons in this report aze properly followed. Additionally, construction of the foundation for the proposed structure and installation of drainage systems and re-vegetation of disturbed areas as describ..d herein, should maintain or improve the long-term stabiliry of the site slopes. 7.0 EROSION HAZARDS AND MITIGATION The on-site sedimencs contain significant amounts of silt and fine sand-sized particles and will be sensitive to erosion, especially given the sloping nature ot the site. To reduce the amount of 6