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HomeMy WebLinkAboutr.20 Plan Review Comments_01222016 (2).pdfPLAN REVIEW COMMENTS U14000114 January 07, 2014 Name: CANYON TERRACE - Summit Homes Application Date:12208 SE 192nd St Renton, WA 98058-7526 Site Address: Instructions: Please be prepared to submit corrections to address ALL plan review comments at one time, including a narrative letter explaining how the comments have been addressed. Please include this document as part of your revision submittal. You will be given a revision form to be completed at the tim of resubmittal. ENG - Construction Permit Review Version 1 | January 22, 2016 Engineering Review Comments Contact: Ann Fowler | 425-430-7382 | afowler@rentonwa.gov Driveway comments Provide driveway stationing for lots 35 54. Pond Breach Repair Comments 1) Provide the following information: a) a summary of the design plans and specifications for the berm location, b) logs of existing subsurface explorations in the Pond berm area, along with a site plan showing the exploration locations and a summary of these conditions, and c) a description of grade changes as a result of mass grading for the Canyon Terrace project (how much fill has been placed at the Pond berm location). 2) Provide details for additional subsurface exploration which should be completed to properly evaluate the conditions of the overlying fill and the depth to the “top of the dense soil.” As a note, the hand auger method of exploration is not adequate for obtaining this subsurface data at this location considering the expected soil conditions and depth of exploration (more than 10 feet). Exploration should be completed with mechanized drilling equipment capable of Standard Penetration Test (SPT) soil testing. If no explorations are to be completed, provide adequate reasoning for not obtaining subsurface data that provides a basis for the cement treated key being an adequate method of repair. 3) Provide additional details regarding the “cement treated key” that is proposed for the berm repair including: a) The settlement and potential cracking caused by differential settlement for this type of rigid seepage barrier. b) How deep the key will need to be constructed (provide specific description of the character of the underlying “dense soils” and seepage conditions based on subsurface data). c) Discussion and recommendations, for the junction with the existing concrete wall and the new fill berm/key (a possible seepage zone). d) Should the key be embedded a specific depth into the underlying dense soils? e) Slope stability analysis should be completed using the cross sectional berm geometry, groundwater conditions at full pond level and rapid pond drawdown conditions. Is the existing berm, even with a key, adequate in cross section and level of compaction, to provide long term slope stability? f) Describe any other issues related to constructability of the key, or at least provide a discussion on how this key can be constructed (shallow groundwater, caving soils in the key excavation, and other issues). g) Are there conditions such that groundwater seepage may go “around” the key and destabilize the adjacent fill slope? h) Are there other alternatives for the key other than cement treated base or controlled density fill? 4) Is reconstruction of the existing crushed rock berm needed? If not, provide an explanation. 5) Provide recommendations for monitoring the reconstruction of the berm and installation of the key. This monitoring should be completed by a professional engineer or licensed engineering geologist. It is essential that extending the key into the underlying “dense soils” is well documented. Wall Drain Comments Clean outs are required at pipe bends. Recommend the pipe to run parallel to the roadway, crossing the roadway at a 90 degree angle and entering the catch basin. Planning Review - Construction Permit Comments Contact: Rocale Timmons | 425-430-7219 | rtimmons@rentonwa.gov 1. Landscaping Plan not included in submittal. Page 1 of 1Ran: January 22, 2016