4704 HARBOR LN 2018-01-02 MF Import

Engineors/Consultants Job#4057 180ct09 To: Chris & Todd Chase / Everett, WA From: Frank Pita, PE / Geotecimical & Civil Engineer RE: Engineering Comments / Concerns After Reviewing the Four Sheet Retaining Wall Design by CG Engineering (dated 24Sep09 / Job#09117.10) for the Anderson's at 4704 Harbor Lane, Everett, WA / Everett Plan Check No. 80910-019 I will comment on each sheet in order and summarize at the end. Sheet SO.1 • In the Scope of Work section; the designer states that his work will '...stabilize the existing slope.' 1 disagree with this statement. This soldier pile wall will ONLY prevent the top few feet of the hillside from eroding or failing but in will NOT make the hillside stable. Much more work is needed to do that. I recommend that the scope of work should be re -written to be more specific to what they are actually doing. • On the Site Plan there are several un-answered issues: o The surveyed pile of yard waste; is it to remain? Is it being placed there illegally in that it is dumping of material that is on the side slope of creek and could easily create a landslide onto adjacent property? o The north end of the wall is NOT detailed from an earthwork aspect. The contours do not show how the backfill is tied into the existing ground and the property to the north. The concern is will this work cause erosion or a landslide on the property to the north. o No elevations are given for the property on the southeast side of the house. Sheet SLI (the text portion) First column; • Code: designer refers to 113C, but does not the City of Everett, like most Washington Cities, use WSDOT specs as there standard design code? • Design Loads.... 3"t paragraph: indicates that '...lessor of 2 pile diameters...' the question is did the design use the steel width or the diameter of the hole? • Allowable grout to soil adhesion.... Where did value come from? There is no reference. Second column; • Erosion...: this designer refers to the geotech report for specifications but the geotech report is NOT complete and refers to the 'wetland' firm, which is not complete either. Therefore, the conclusion has to be that Erosion and Sedimentation is NOT being control properly. The recommendation to carry the water to the bottom of the ravine still requires an agreement with the adjacent property owner which is not discussed. 1109 1" Avenue, Suite 501, Seattle, Washington 98101 Phone: (206)5884200 Fax: (206)588-8201 Page I i371y