11419 19TH AVE SE Geotech Report 2018-01-02 MF Import

� ( ' 12.0 Pavement Recommendatiuns, continucd � Arcas to be pavcd should be preparcd in accordance with Section 7.0. After the paved areas are prepared in such a manner, the exposcd ground should bc recompacted to a minimum of 92 percent � of ASTM: D1557 and to a firm, non-yieldin�condition. If required, structural fill may then be placed to achieve desired subbase grades. If the subgrade contains too much moisture to achieve the required compaction, the wet material should either be removed and replaced or cement and/or fly � ash may be used ro dry the materiaf in place. The amount of cement and/or fly ash needed to be tilled or disked into the soil �viil depend on the moisture content of the wet azeas at the time of construction and should be determined by the geotechnical engineer. Upon completion of the � recompaction and placement of structural filf if necessary, we recummend tha[ subgrade be prooF rolled with a large, fully loaded dump truck across the entire azea to be paved under the observation � of our;eotechnical engineer. In this way, any soft or yielding azeas may be identified and repaired prior to placing the pavement. Rutting or pumping shall indicate an unsatisfactory subgrade condition and that material should be overexcavated as directed by the soils engineer,then backfilled � with structural filL Proof ro(lir.g should be performed when weather and soil moisture conditions permit. � Once the proof roll has been completed and all soft or yielding areas repaired, the subbase material should be placed and compacted. The subbase should consist of Z inches of 5/8 crushed rock surfacing top course over 3 inches of 1-1/4 inch crushed rock base course as the recommended � minimums. The crushed rock base courses must be compacted to 95 percent of theic maximum dry density (ASTM: D1557). A minimum 3 inch thickness of Washington State Class B asphalt concrete pavement should then be placed and suitably compacted. � 13.0 Project Design and Construction Mooitoring 1 At the time of thi< report, grading plans and structural design drawings for the site had not been completed. We recommend tha[a representative of our firm perform a geotechnical review of tlta plans and specifications prior to final design completion. In this way, our earthwork and foundation 1 recommendations may be properly interpreted and implemented in the design. We are aiso available ro provide geotechr.icai engineering and monitonng services during ' construction. The integrity of the foundation depends on proper site preparation and construction procedures. In addition, engineering decisions may have to made in the fteld in the event that � variations in the subsurface conditions become apparerrt. � ' 1 � � ��6 I MAYES TESTING ENGIN�ERS