Laserfiche WebLink
4, <br />Ruffridge Johnson Equipment Company <br />Centerville, Minnesota <br />NTI Project No. 17.61877.100 <br />Without documentation of the placement of the fill soils (Parcel B), it is NTI's opinion that they are <br />not suitable for direct support of the foundations or floor slabs and that they may not provide a <br />uniform subgrade support. Additionally, the organic laden soils are not suitable for support of <br />foundations or slabs. These may be limited in extent, but, even with documentation, we recommend <br />that they be removed from the building area. <br />If the floor slab is to be supported on the existing, non-organic, fill soils, there is the potential for <br />increased distress within the floor slab. If this option is selected, the modulus of subgrade reaction <br />(k) design value should be reduced to 150 pci (pounds per square inch per inch of depth). The risk of <br />differential settlements in the slab could be reduced if the upper 1 foot, or more, of the slab <br />subgrade is over -excavated and replaced with properly compacted granular backfill. <br />If the floor slab is to be constructed directly over documented engineered fill or non-organic, <br />competent native soil as described in the Site Preparation section of our geotechnical report, the <br />design of the floor slab may be based on an estimated modulus of subgrade reaction (k) of 200 pci. <br />Maximum net allowable soil bearing pressure recommendations for founding the foundation on <br />native soils with on-site documented backfill that should be used for design is 2,500 pounds per <br />square foot (psf). Maximum net allowable soil bearing pressure recommendations for founding the <br />foundation on newly prepared properly compacted fill soils or competent native soils that should be <br />used for design is 3,500 psf. <br />These recommendations are predicated on foundation design and construction complying with <br />recommendations presented within our geotechnical report. To minimize local failure of supporting <br />soils, it is our opinion foundation construction should comply with the International Building Code <br />(IBC) requirements. <br />If the Owner, in conjunction with the design team, wishes to explore an option to support the <br />proposed structure on the existing fill soils, NTI suggests that a series of test pits be advanced at the <br />site to refine our understanding of the fill soil profile prior to construction. Additionally, to aid in <br />evaluating the fill soil conditions, density testing of the in-place fill soils could be performed within <br />building pad area. <br />We appreciate the opportunity to have been of service on this project. If there are any questions <br />regarding the soils explored or our review and recommendations, please contact us at your <br />convenience at (651) 389-4191. <br />Northern Technologies, LLC <br />__i� �___ <br />Debra A. Schroeder, P.E. <br />Senior Engineer <br />Steven D. Gerber, P.E. <br />Senior Engineer <br />Attachments <br />