1617 EDGEMOOR LN 2016-11-10 - Laserfiche WebLink

4= �■■■�� civil & structural ENGINEEFUNG engineering & planning Project: McKinnon Residence Retaining Wall Purpose: Final Observation Letter Location: 1617 Edgemoor Lane, Everett, WA Date: June 9, 2016 CG Project: 15038.10 Permit # B1505-004 Report: 1 Client•' Bruce McKinnon General Contractor: Advanced Foundation Supports & Bodine Construction Services Field Rep: Greg Guillen, PE, SE As requested by the city of Everett construction inspector Randy Allen, a field representative from CG Engineering was on site on to review the completed construction of a new retaining wall system and drainage improvements project at the above referenced address. This field observation was attended with the geotechnical engineer of record Mr. Khaled Shawish, PE of Nelson Geotechnical to review the final constructed project from a structural and geotechnical perspective. During construction several minor modifications were implemented to the construction drawings due to a shorter than predicted wall height from 5 feet anticipated to approximately 3 feet. Also the small steel premanufactured garden shed that was to be located further down slope at the northwest side of the property line was moved up into the yard to save costs on the wall requirements. The original plan showed the wall jogging out downslope creating a fill situation and costly wall construction so this minor change was completed in the field with a modification to the drawings on July 21, 2015 (Photo 4). Many minor changes to the drainage systems were performed by Bodine Construction Services once the existing drainage pipes and catch basins were investigated. These changes have been well documented by the owner of the property above. The notes on the grading and drainage plan call for the drainage contractor to connect all the roof, footing, and catch basin drains to the new Nyloplast catch basin located behind the wall near the southeast of the project. The contractor installed a perforated drain near the patio that essentially runs the entire length of the back yard. All the drainage from this property is then taken downslope approximately 125 feet to an old logging road where a dispersal "T" is installed that lets the water out slowly over a larger area (Photos 1 & 3). OBSERVATIONS & RECOMMENDATIONS The retaining wall was constructed in a professional manner and the drainage systems appeared to be functioning correctly with the exception at the dispersal "T" near the logging road where it was discovered that the northern end cap had blown off of the dispersal "T". This we believe is due to concrete paste washed off of the newly placed exposed aggregate concrete drive way completed with this project (Photo 2). It appears as though that the concrete paste from the exposed aggregate concrete placed has plugged the two sets of holes drilled in the "T". We recommend that the drainage contractor go back to the site and clean out the concrete paste out of the dispersal "T" and re -level the "T" so that storm water can flow out the system evenly. The 250 4th Avenue South, Suite 200 Edmonds, WA 98020 ph.425.778.8500 1 f.425.778.5536 www.cgengineering.com