1618 HOLBROOK AVE 2018-01-02 MF Import

Temporary Ultra_ Block Wall Detail (Not to Scale) 12.5-feet 2.5-feet 12-in. (min.) Native Medium Dense Subgrade Note: Overexcavate Loose Material and Replace with Rock Spalls 1-foot minimum Top Row: Row 5 (see table below) 2 to 4-inch Rock Spalls Bottom Row: Row 1 (see table below) 4 Rigid Perforated Drain Pipe Mirafi 140N Filter Fabric Basal Crushed Rock Layer: 6-inch Minimum Number Or Blom WullW reb now Design Wall Height 1 2 7 4 5 5.0 1 1 x z x 7.5 2 2 1 x x 10.0 12.5 I 2 2 2 2 1 1 1 1 x 1 SPECIFICATIONS FOR WALL General 1. The contractor shall have an approved set of plans and specifications on site at all times during the construction of the wall. The wall layout is the responsibility of the contractor. 2. Nelson Geotechnical Associates (NGA) should observe and monitor the construction of the wall. 3. The joints between blocks should be staggered. Subgrade Preparation 1. The ground should be prepared by removing surficial unsuitahle soil, down to dense, inorganic, native soils as approved by the geotechnical engineer. 2. The excavation shall be cleaned of all excess material and protected, as necessary, from construction traffic to maintain the integrity of the subgrade. 3. The base of the excavation should be deep enough to satisfy a minimum embedment of "-foot to final grade at the toe of the wall, and should be sloped down toward the cut to provide a batter of 1 H:9V to the face of the wall. Drainage 1. A drainage blanket 12 inches in width should be installed directly behind the block facing and shall consist of 2- to 4-inch rock spalls or washed rock. All of the drainage materials shall have a fines content no greater than three percent passing the number 200 sieve. A 4-inch rigid perfo-mled pipe embedded in a minimum of one foot of pea gravel or washed rock and wrapped with filter fabric should be installed at the bottom of the drainage blanket 2. Suitable clean -outs should be installed for future ma7ntenance and the drain should be tightlined to daylight with a minimum fall of one percent. Design Parameters Retained Soil: 34 degrees, 0 PSF, 125 PCF Foundation Soil: 34 degrees, 0 PSF, 125 PCF External Stability of Wall Minimum Factor of Safety against Base Sliding: 1.5 Minimum Factor of Safety against Overturning: 2.0 Minimum Factor of Safety against Bearing Capacity: 2.0 Inspection Wall construction shall be periodically inspected under the direction of an engineer registered in the state of Washington with experience in the design of retaining walls. Y U r m W w m 5 CD J 6 Z 00 U Lo w 0 O cc 7i 2 7 0) LL