HomeMy WebLinkAboutApplicant Response to Secondary Geotechnical Review Comments
Corporate Office
17522 Bothell Way Northeast
Bothell, Washington 98011 Phone 425.415.0551 ♦ Fax 425.415.0311
www.riley-group.com
October 23, 2020
Ms. Valery Kalashnikov
Nord West Properties, LLC
13220 42nd Avenue East
Tacoma, Washington 98446 RE: Response to Draft Comments
Aberdeen Townhomes
957 Aberdeen Avenue Northwest
Renton, Washington
RGI Project No. 2018-223
References: Encompass Engineering and Surveying, Preliminary Grading and Drainage Plan
dated October 8, 2020
The Riley Group, Inc. Geotechnical Engineering Report revision dated September
2, 2020
Dear Ms. Kalashnikov:
As requested, The Riley Group, Inc. (RGI) is providing this letter to respond to the City of Renton
Draft Comments dated October 15, 2020
Comment 1: In Section 4.6.6, RGI states “RGI completed a stability analysis for the currently
proposed conditions as shown on the plans and included the proposed drainage facilities.” and
indicates modifications that were made to the reviewed plans from a previous version. We
suggest that RGI reference a date or other unique indicator of which version of the plans were
reviewed and used as a basis of analysis. Alternatively, RGI could provide a review letter or other
appropriate confirmation indicating that they have reviewed the final plan set and that it is
consistent with their assumptions and recommendations as they recommend in Section 6.0.
RGI Response: RGI reviewed the referenced preliminary civil engineering plans and found them
consistent with the referenced geotechnical engineering report.
Comment 2: In Appendix B, RGI states “The analyses were performed for the existing conditions
under static and seismic loading condition, as well as the proposed conditions.” The existing
condition analysis was not provided, and the results of the existing condition analyses were not
indicated. These should be provided so the calculated stability of the existing conditions can be
compared to the calculated stability of the proposed conditions. This comparison can directly
demonstrate that the development meets the criteria of Renton Municipal Code Section 4-3-
050F.2.a.ii.(a) “The proposal will not increase the threat of the geological hazard to adjacent or
abutting properties beyond pre-development conditions”. This is specifically critical for Section
B-B’ that extends to the adjacent property to the north.
RGI Response: The analyses for existing conditions are attached.
Comment 3: The analysis indicates that a horizontal seismic coefficient of 0.2g was applied. It is
not clear what seismic design level (i.e., return period) this is based on or if a reduction was
included. A seismic event with a 2 percent probability of exceedance in 50 years (about 2,475-
1.6001.600111.6001.600Material NameColorUnit WeightlStrength TypeCoheionlPhiWater SurfaceRuSilty sand125Mohr-Coulomb20036Piezometric Line 1Silt110Mohr-Coulomb40034None0Safety Factor0.0000.2500.5000.7501.0001.2501.5001.7502.0002.2502.5002.7503.0003.2503.5003.7504.0004.2504.5004.7505.0005.2505.5005.7506.000+275250225200175150125-120-100-80-60-40-20020406080100120Analysis DescriptionExisting Static A-A'CompanyRiley Group, Inc.Scale1:310Drawn ByELWFile NameExisting Static A-A'.slimDate11/20/2018, 10:14:49 AMProjectAberdeen TownhomesSLIDEINTERPRET 6.009
1.6671.66711.6671.667Material NameColorUnit WeightlStrength TypeCoheionlPhiWater SurfaceRuSilty sand125Mohr-Coulomb20036Piezometric Line 1Silt110Mohr-Coulomb40034None0Safety Factor0.0000.2500.5000.7501.0001.2501.5001.7502.0002.2502.5002.7503.0003.2503.5003.7504.0004.2504.5004.7505.0005.2505.5005.7506.000+275250225200175150125-150-125-100-75-50-250255075100Analysis DescriptionExisting Static - B-B'CompanyRiley Group, Inc.Scale1:322Drawn ByELWFile NameExisting Static B-B'.slimDate11/20/2018, 10:14:49 AMProjectAberdeen TownhomesSLIDEINTERPRET 6.009
2.0402.04012.0402.040Material NameColorUnit WeightlStrength TypeCoheionlPhiWater SurfaceRuSilty sand125Mohr-Coulomb20036Piezometric Line 1Silt110Mohr-Coulomb40034None0Safety Factor0.0000.2500.5000.7501.0001.2501.5001.7502.0002.2502.5002.7503.0003.2503.5003.7504.0004.2504.5004.7505.0005.2505.5005.7506.000+300250200150-175-150-125-100-75-50-250255075100125Analysis DescriptionExisting Static - C-C'CompanyRiley Group, Inc.Scale1:374Drawn ByELWFile NameExisting Static C-C'.slimDate11/20/2018, 10:14:49 AMProjectAberdeen TownhomesSLIDEINTERPRET 6.009
1.6001.60011 150.00 lbs/ft21.6001.600Material NameColorUnit WeightlStrength TypeCoheionlPhiWater SurfaceRuSilty sand125Mohr-Coulomb20036Piezometric Line 1Silt110Mohr-Coulomb40034None0Fill125Mohr-Coulomb036None0Safety Factor0.0000.2500.5000.7501.0001.2501.5001.7502.0002.2502.5002.7503.0003.2503.5003.7504.0004.2504.5004.7505.0005.2505.5005.7506.000+275250225200175150125-50-250255075100125150175200Analysis DescriptionProposed Static A-A'CompanyRiley Group, Inc.Scale1:311Drawn ByELWFile NameProposed Static.slimDate11/20/2018, 10:14:49 AMProjectAberdeen TownhomesSLIDEINTERPRET 6.009
1.6671.6671 150.00 lbs/ft21.6671.667Material NameColorUnit WeightlStrength TypeCoheionlPhiWater SurfaceRuSilty sand125Mohr-Coulomb20036Piezometric Line 1Silt110Mohr-Coulomb40034None0Fill/Tank100Mohr-Coulomb036None0Safety Factor0.0000.2500.5000.7501.0001.2501.5001.7502.0002.2502.5002.7503.0003.2503.5003.7504.0004.2504.5004.7505.0005.2505.5005.7506.000+275250225200175150-60-40-20020406080100120140160180Analysis DescriptionProposed Static - B-B'CompanyRiley Group, Inc.Scale1:290Drawn ByELWFile NameProposed Static B-B'.slimDate11/20/2018, 10:14:49 AMProjectAberdeen TownhomesSLIDEINTERPRET 6.009
2.0402.0401 150.00 lbs/ft22.0402.040Material NameColorUnit WeightlStrength TypeCoheionlPhiWaterSurfaceRuSilty sand125Mohr-Coulomb20036PiezometricLine 1Silt110Mohr-Coulomb40034None0Safety Factor0.0000.2500.5000.7501.0001.2501.5001.7502.0002.2502.5002.7503.0003.2503.5003.7504.0004.2504.5004.7505.0005.2505.5005.7506.000+300250200150-75-50-250255075100125150175200225Analysis DescriptionProposed Static - C-C'CompanyRiley Group, Inc.Scale1:374Drawn ByELWFile NameProposed Static C-C'.slimDate11/20/2018, 10:14:49 AMProjectAberdeen TownhomesSLIDEINTERPRET 6.009
1.0641.06411 150.00 lbs/ft21.0641.064Material NameColorUnit WeightlStrength TypeCoheionlPhiWater SurfaceRuSilty sand125Mohr-Coulomb20036Piezometric Line 1Silt110Mohr-Coulomb40034None0 0.23Safety Factor0.0000.2500.5000.7501.0001.2501.5001.7502.0002.2502.5002.7503.0003.2503.5003.7504.0004.2504.5004.7505.0005.2505.5005.7506.000+275250225200175150125-50-250255075100125150175200Analysis DescriptionProposed Seismic A-A'CompanyRiley Group, Inc.Scale1:310Drawn ByELWFile NameProposed Seismic A-A'.slimDate11/20/2018, 10:14:49 AMProjectAberdeen TownhomesSLIDEINTERPRET 6.009
1.1261.1261 150.00 lbs/ft21.1261.126Material NameColorUnit WeightlStrength TypeCoheionlPhiWater SurfaceRuSilty sand125Mohr-Coulomb20036Piezometric Line 1Silt110Mohr-Coulomb40034None0Fill/Tank100Mohr-Coulomb036None0 0.23Safety Factor0.0000.2500.5000.7501.0001.2501.5001.7502.0002.2502.5002.7503.0003.2503.5003.7504.0004.2504.5004.7505.0005.2505.5005.7506.000+260240220200180160140-40-20020406080100120140160180Analysis DescriptionProposed Seismic - B-B'CompanyRiley Group, Inc.Scale1:281Drawn ByELWFile NameProposed Seismic B-B'.slimDate11/20/2018, 10:14:49 AMProjectAberdeen TownhomesSLIDEINTERPRET 6.009
1.2981.2981 150.00 lbs/ft21.2981.298Material NameColorUnit WeightlStrength TypeCoheionlPhiWater SurfaceRuSilty sand125Mohr-Coulomb20036Piezometric Line 1Silt110Mohr-Coulomb40034None0 0.23Safety Factor0.0000.2500.5000.7501.0001.2501.5001.7502.0002.2502.5002.7503.0003.2503.5003.7504.0004.2504.5004.7505.0005.2505.5005.7506.000+300250200150-50-250255075100125150175200225Analysis DescriptionProposed Seismic - C-C'CompanyRiley Group, Inc.Scale1:374Drawn ByELWFile NameProposed Seismic C-C'.slimDate11/20/2018, 10:14:49 AMProjectAberdeen TownhomesSLIDEINTERPRET 6.009