5213 GLENWOOD AVE 2017-03-09 - Laserfiche WebLink

r Revised Red-Rock Retaining Wil Design Western Geotechnical Consultants,rnc. 52XX Glenwood Ave_Property tr 14 91 2 Everett,WA April 17,2015 top block. When the wall is 9 blocks or less, the wall can be constructed as a gravity wall. The transition between the gravity wall and the MSE geogrid wall will require the geogrid to extend one block into gravity wall (from the top of the base block to the base of the top block) to convert to a gravity wall in a unifrn-m way. Below we provide a design for both a gravity wall and a MSE wall. Gravity Wall (:53: Blocks High) The retaining wall proposed will vary in height from 2 blocks high to 15 blocks high. Where the retaining wall is less than 9 blocks high,a gravity wall may be constructed. Where a gravity wall is utilized the width of the blocks will vary from 28 inches at the top to 60 inches wide below -- feet Appendix B contains design cross-sections for walls between 4 and 9 blocks high. The blocks above the 60 inch deep base blocks required are to be 41 inch deep blocks except for the top block. The top block on all wall heights is to be a 28 inch deep block. Wall cross-sections and supporting calculations arc presented in Appendices B and C" to this report We analyzed wall heights up to 9 blocks high (15 foot maximum height). We analyzed wall sections for the site using the Redi-Rock gravity wall design computer program. We were unable to print out our cross sections from the Redi-Rock gravity wall design computer program that provided sufficient detail for the wall builder, so we went to the Redi-Rock web site and we obtained typical preliminary wall sections appropriate for the subject site, which provide the Redi-Rock wall sections that are appropriate for this design_ We have included the computer generated cross- sections together with our supporting calculations in Appendices B and C' to this report together with hand calculated stability analyses for a 10 block wall (15 feet), The design cross-sections contained in Appendix B should be used by the wall contractor in building the wall. Note that the cross sections are called preliminary, but these wall sections were checked and they are appropriate for the design conditions at the subject site. The wall design calls for crushed stone backfill behind the wall meeting the minimum standards of ASTM No. 57 (crushed stone with an internal friction angle of 40 degrees required). Note that the high quality gravel (ASTM No. 57) used as backfill is why this wall is stable to the heights desired as a gravity wall. Otherwise, geogrid will he required behind the Redi-Rock wall, as detailed in the next section to this report. A. non-woven geotextile is required between the crushed stone backfill and the native soil as shown on the Typical Cross-Section in Appendix A. We recommend TcnC'ate Cieosynthetics, Mirafi 160N as the appropriate geotextile for the given soil conditions. I1)SE V4 gill (> 9 Blocks Hight Due to the height of the wall, the lateral loading caused by the backfill soils, as well as possible earthquake loading, we designed a Mechanically Stabilized Earth(MSE) wall using Redi-Rock Facing for all wall sections with greater than 9 blocks. The MSE wall consists of geogrid reinforced select fill behind the wall with the geogrid connected to the Redi-Rock system to provide a stable wall section for the design loading. A typical cross-section of an MSE Redi- rock wall is included in Appendix A to this report. 4