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Mr. Andrew Janzen December 22, 2023 <br /> Site Inspection Page 12 <br /> 3624 Upland Ave <br /> Everett, WA <br /> GEOLOGICAL SETTING AND SOILS <br /> The geologic setting in this area is comprised of deposits of clay silt and fine to very fine sand <br /> defined as Fraser Glaciation, Transitional Beds (USGS National Geologic Map Database). <br /> According to Washington Geologic Information Portal, the site is considered a high landslide <br /> hazard and is relatively sloped. <br /> Preliminary soil data was obtained from the Web Soil Survey from Natural Resources <br /> Conservation Service produced by the United States Department of Agriculture.This soils survey <br /> indicates that the primary soil at the structure is classified as Alderwood-Everett gravelly sandy <br /> loarns. This soil has a moderate to high infiltration rate and a moderate to high rate of water <br /> transmission. Alderwood-Everett gravelly sandy loams has a low shrink-swell potential and is <br /> considered non-plastic with a maximum Plasticity Index of 5. <br /> OBSERVATIONS <br /> Vegetation around the structure consists primarily of grassy areas with some small to large <br /> shrubs.The surface grades on the north and west sides of the structure appear adequate to drain <br /> water away from the foundation. The surface grades on the south and east sides of the structure <br /> appear to be negatively sloped toward the foundation. No areas of ponding water were observed <br /> on any side of the structure. <br /> Some evidence of foundation movement was observed during the inspection which is noted on <br /> the attached Foundation and Elevation Assessment Plan (SK-1). The evidence consisted <br /> primarily of cracks in the side of the wall. <br /> RECOMMENDATIONS <br /> It is our opinion that the erosion observed at the site is a result of storm water action associated <br /> with the sandy soil present on the slope. First and foremost, erosion needs to be detained to <br /> safeguard the integrity of the wall. We believe that a suitable repair can be achieved by using <br /> expansive foam and by installing helical piles and helical tiebacks. <br /> As a voluntary repair, and based on the straightforward assessment of the site conditions related <br /> to the erosion, a full geotechnical report is not necessary specifically for the erosion issue. The <br /> repairs proposed herein will address the immediate and necessary corrections of the damages <br /> caused by erosion. However, in order to assess the overall stability of the slope, which will go <br /> beyond the wall in question, a geotechnical report is recommended to provide additional <br /> recommendations. The global stability analysis is beyond the scope of this project. <br /> We recommend the injection of a two-part expansive foam to the depth of 4 ft in order to penetrate <br /> the voids created by erosion. Also,we recommend a total of five (5) helical steel piles and three <br /> (3) helical steel tiebacks be installed at the structure. Pile locations are shown on the Foundation <br /> and Elevation Assessment Plan (SK-1). The steel piling system used should have an evaluation <br /> service report (ESR) recognized by ICC-ES showing compliance with the currently adopted <br /> International Building Code (IBC). Refer to the attached drawings for the minimum allowable <br /> working load and the minimum installation torque for each pile and tieback. <br /> P.Q.BOX 10393/Eugene,OR,97440/541.393.7363/WWW.NWENGGROUP,COM <br />