4937 SEA BREEZE WAY 2017-01-13 - Laserfiche WebLink

� Geotechnical Engineering Evaluation Pepe Retaining Wall Everett, VVashington NGA File No. 916915 April 27, 2015 Page 2 Our initial visit to the site was on February 16, 2015 wllere we met with the realtor, Ms. Joyce Morill of RemaY Northwest Realtors, to observe the existing conditions in an Initial Assessment eval�►ation. We observed that the sidewalk along the housc in this area was undermined by several inches. On the soutl�ern side of the house, we observed areas of past s(ope instability including a large evergreen tree that was leaning towards the house. Sevei�al severe cracks were observed within the garage and lower level of the house, inclucling a crack on the outside in the foundation on the southern side of the ho�ise. At that tiine, we observed that the roof drains were directed into pipes in the ground and the pipes were outletting on the slope below the wall. We did not obsecve any other drainage systems s��ch as foundation drains around the periineter o1'the house. Also, we did not evaluate the remainder of the house due to all of the slleet rock and walls had been removed prior to our visit. We should stress that this study is only for the failing wall and not for the ]louse or the overall site. Additional explorations and analysis wo�ild be needed to provide specitic recommendations on how to remedy tlle issues within the house and the overall site. We recommend that sticll a study be conducted as there was strong evidence that the house and remainder of the property are eYperiencing distress that wo�ild not be initigated by tl�e proposed repairs to the wall. SCOPE The purpose of this st�idy is to explore and characterize the site s�irface and subsurface conditions only aro�ind the failin� retaining wall, and provide general recommendations for repairs and stabilization of the retaining wall. Specifically, our scope of�services includes thc following: 2. 3. 4. 5. 6. 7. 8. Review existing soils and geologic maps of the area. Explore the subsurface soil and gro�indwater conditions within the wall vicinity with trackhoe-excavated test pits. Trackhoe was subcontracted by NGA. Map the conditions on the slope below the wall and to the south of the residence, perform hand-tool excavations, and evaluate current slope stability conditions. Perform grain-size sieve analysis and classification of soil samples, as necessary. Provide our opinion of tlle existing retaining wall and the most cost-effective measures for repair or replacement of the wall. Provide general recommendations for earthwork. Provide general recommendations for temporary and pennanent slopes. Provide recommendations for improving site drainage and erosion control. NELSON GEOTECHN/CAL ASSOC/ATES, INC.