10200 25TH AVE SE Geotech Report 2018-01-02 MF Import

f. Proposed b.o irn.iEation nnd Additions to Subsurface Exploration, Geo[ogic Hazardr, Eisenhower l9iddle School and Geotechnical Engmeering Repon Everea, Wiuhin ron �� Desixn Recommend:tions from the building. In addition, al: retaining walls and modular block walls sb.ould be lined with a minimum 12-inch-thick washed gravel blanket provided to within 1 foot of the top of wall, and which ties into the fcnting drain. Modular block walis should also be provided with chimney drains. Roof and surface runoff should not discharge into the footing drain system but should be handfed by a separate, rigid, tightline drain. Exterior grades adjacent to walis should be sloped downward away from the structure to achieve surface drainage. 14.0 PAVEMENT RECOMMENDATIONS Pavement design will depend ro some extent on the soil that esists beneath the area to be paved. Where paving is planned above areas of existing fill we recommend that the paving section be constructed above at least 2 feet of new, properly compacted, granular structural fill or the existing fill recompacted to the minimum specified compaction required for structural fill. The 2 feet of structural fill below the pavement can be provided hy the removal and recompaction of existing fili soils where moisture is within the compa[ible range. The new structural fill will not be required beiow paving areas that are dirPrtly underlain by suitable till. We recommend that paving subgrades be :•ompacted to 95 �;ercent of the modified Proctor maximum dry density as determined by ASTM:D 1557 and to a firm, unyielding condition. Following compaction, the areas to be paved should be proof-rolled with a loaded dump truck or other suitable equipment under the observation of the geotechnical engineer. Any soft, loose, or yieiding areas identified by proof-rolling should be repaired prior to further work. Following subgrade preparation, we recommend a passenger car pavement section consisting of a 2�h-inch compacted asphalt pavino above a 4-inch compacted crushed rock base. In areas where buses, garbage trucks, fire trucks, defivery trucks, or other heavy vehicles will be driven or parked, we recommend a paving section consisting of 4 inches of asphalt paving above 6 inches of crushed rock base. Pavement thickness desion is a compromise beiween higher initial cost wit;: longer design life II and lower maintenance, and lower initial cost with higher maintenance requirements and �� shorter design life. The recommended pavement sections are intended to provide a 20-year service life with normal maintenance. Normal maintenance rypically includes periodic sealing, and at least one renovation that includes repair and overlay of damaged areas. 15.0 PROJECT DESIGN AND RECOMNIENDATIONS FOR FURTHER STUDY We are available to provide additional georechnical consultation and exploration where the project design chan;es from that upon which this report is based. We recommend that AESI perform a geotechnical review of the plans prior to final design completion. In this way, our earthwork and foundation recommenda[ions may be properly interpreted and implemented in J°7O�n� �3• ��'� dSSOG.aT£D E�RTN SCI£�VCES. 6VC. � .4lT�ld-XEOJ:J.4:1J-Prn�rntiClXli:i9lKE�lYP-117K P3gE ZO �