11611 AIRPORT RD Geotech Report 2018-01-02 MF Import

� � Geo[echnical Gngineering Keport Vroposed Ahn �i'arehouse May l l, 2001 C'G File No. 1121 Page 12 dmining material. A Icss permeable soil should be placed in the last 1 foot to reduce surface infiltration into the wall drain. All wall backfill materials should be approved by the geotechnical engineer prior to placement. A slotted drainpipe having a minimum diameter of 4 inches should be embedded in pca gravel or some other free-draining material, at the base of the wall, along its entire length. This drainpipe should discharge into tightlines leading to an appropriate collection and discharge poinL Roof drains should not be connected to wall or footing drains. Slabs-Ou-Grade Slab-on-grade areas should Ue prepared as recommended in the Site Preparation and Grading subsection. To minimize settlement and potential cracking of the concrete slab, it is best to support the slabs on medium dense to very dense native soils, or on structural fill extending to these soils. To reduce potential settlement of the slab,we recommend that the upper 2 feet of fii] of the slab be replaced with structural fill. This should be accomplished as described in the Structural Fill subsection of this report. Where moisture control is a concern, we recommend tiiat slabs be underlain by 6 inches of free- draining sand or gravel for use as a capillary break. A suitable vapor bamer, such as heavy plas[ic sheeting, should be placed over the capillary break If desired, a sand blanket could be placed over the vapor barrier to aid in curing of the concrete. Drainage We recommend that runoff ftom impervious surfaces, such as roofs, driveway and access roadways, be collected and routed to an appropriate stornt water discharge system. Final site grades should allow for drainage aH ay from any buildings. We suggest that the {inished ground surface be sloped at a gradicnt of 3 percent minim�m for a distance of at least 10 feet away :rom the buildings. Surface water should be collected by permanent catch basins and drain lines, and be discharged into a storm drain system. We rccommend that ti�oting drains be used around all of the structures where moisture contrul is important. 'Ihe site soils wi11 tend to pond water. [t is good practice to use footing drains installed at Icast I foot below planned Finished floor slab elevation. 1f drains are omittec:around Cornerstone Geotechnical, Inc. � J �j) ;��