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~: <br /> <br />3) The piers should be reinforced their full length with at least one #5 reinforcing rod for each 16 <br />inches of pier perimeter. <br />4) The piers should be properly cleaned and dewatered prior to steel and concrete placement. <br />5) A 4-inch void should be provided beneath grade beams to prevettt the swelling soils from exerting <br />uplift forces on the grade beams and to concentrate pier loadings. Avoid should also be provided <br />beneath necessary pier caps. <br />7) This office should be retained by the client observe the pier drilling operations. <br />An alternative deep foundation system to the drilled piers is a helical screw pile foundation system. The <br />helical screw pile foundation system should be designed by a qualified engineer, using industry standazds <br />and be installed by a licensed/certified installer. A minimum penetration of 3 feet into the underlying <br />bedrock materials is recommended. We strongly recommend that at least one test pile be advanced at the <br />site so that the torque versus depth relationships can be established and the proper shaft and helix size and <br />type can be determined. <br />Floor Slabs: We have assumed that structures will be constructed utilizing concrete slab-on-grade floor <br />• systems. The on-site soils, with the exception of the topsoil and organic materials, aze suitable to support <br />slab-on-grade construction. However, floor slabs present a diffiwlt problem where potentially moisture <br />sensitive materials are present near floor slab elevation because sufficient dead load cannot be imposed on <br />them to resist the uplift pressure generated when the materials are wetted and expand. Based on the <br />moisture-volume change characteristics of the natural encountered at this site, we believe slab-on-grade <br />construction may be used, provided the risk of distress resulting from slab movement is recognized and <br />special design precautions are followed. <br />The following measures should be taken to reduce the damage, which could result from movement should <br />the underslab soils be subjected to moisture changes. <br />1) The floor slabs should be separated from all bearing walls, columns and they foundation supports <br />with a positive slip joint. We recommend the use of/z-inch thick cellotex or impregnated felt. <br />2) Interior non-bearing partition walls resting on the floor slabs should be provided with a slip joint, <br />preferably at the bottom, so that in the event the floor slab moves, this movement is not transmitted <br />to the upper structure. This detail is also important for wallboazd and doorframes and is shown in <br />Figure # 10. <br />3) A minimum 6-inch gavel layer should be provided beneath all floor slabs to act as a capillary <br />break and to help distribute pressures. Prior to placing the gravel, the excavation should be shaped <br />• so that if water does get under the slab, it will flow to the low point of the excavation. In addition, <br />fob Number: 03-5838 NWCC, Inc. Page 6 <br />