616 PECKS DR 2018-01-01 MF Import

� � � Everett School District W-68F 1 cy{� N 15 June 1990 Page 8 H Z N �< y (� v "' y ° all footings be evaivated by an RZA representative prior to placement of gravel, quarry � � �` spalls, concrete, or structural fill to confirm that the bearing soils are undisturbed and are °� � o in a condition consistent with recommendations contained within this report. � :° R � H M y Slab-on-Grade Floors � o y In our opinicn, site conditions are suitabie for the use of slab-on-grade fioors, provided � � � the subgrade is properly prepared. Ideally, to minimize fioor settlement and associated N cracking, all existing root-laden soils, or any uncontrolled fill material should be removed and replaced with compacted structural fill. Alternatively, if the owner can accept some risk of floor slab settlement and cracking, it would be acceptable to remove anly the upper 2 feet of inedium dense fill soils and replace them with at least 2 feet of properly compacted structural fill. Regardless of which floor option is selected, the floor subgrade areas should be prepared as described in the Site Preparation section of this report, and structural fill should be placed and compacted as described in the Structurai Fill section. � � We recommend that the floor slab be underlain by a 4-inch minimum thickness of clean � �� sand and gravel, washed rock, or pea gravel to serve as a capiliary break. The capillary break material should contain at lest 40 percent (by weight) gravel-sized particles 1 �� retained by the U.S. No. 4 Sieve, and the fines content should be limited to 3 percent or ��.� less, based on the soil fraction passing the U.S. No. 4 Sieve. Also, an impervious moisture barrier should be placed between the slab and the capillary break material. �� Based on the soil and groundwater conditions encountered in our borings, we do not I �'�� presently anticipate that an extensive below-slab drainage system would be required, provided a perimeter footing drain is installed as described in the Drainage ��) Considerations section in this report. The final decision regarding the need fo� a below slab drainage system should be made based on a field evaluation of on-site greundwater , '� seepage patterns at the time of construction. V�'e wouid be able to offer additional �� design recornmendations should such a drainage system become necessary. � .. Backfilied Walls �1� Althcugh the site plan provided us does not indicate that backfilled walls are included in the buiiding design, �ve are offering the follo�ving recommendations in the event that backfilled �valls may be required. Walls constructed to allow some defiection (on the order of G.1 percent of the wail heiqht) durino bad<fill placement may be designed to