Change Order No 3 - VPA Maintenance Storage Bldg Project No 118-046R - The Robert Henry Corp

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ti Weaver 4k Consultants Group Attn: Mr. John Callan The Robert IIenry Corporation 404 South Francis Street South Bend, IN 46624 RC: SoilObsei-vations South Bend VPA New Storage Building South Bend, Indiana Dear Mr. Callan: November 15, 2018 Project No.: 1459-372-21 As requested, we have visited the reference project on November 13 and 14, 2018 to observe the soil conditions for the new VPA Storage Building. We have observed buried rubble and unsuitable organic soil on the approximate south '/2 of the propose building area and relatively clean suitable granular fill on the approximate north %2 of the proposed building area. We also understand there is an existing concrete floor slab approximately 3 ft below the proposed floor slab in some areas. "Test pits performed on November 14"' indicated the relatively clean granular fill on the north half of the building extended to an approximate depth of 4 ft below the proposed finish subgrade. Measurements with a static cone penetrometer at various elevations in the north '/2 of the proposed building area indicate the fill and the natural soil conditions are suitable for structural support pending additional compaction. We understand the foundations are design for support of foundations using a 2,000 psf bearing capacity. No deep soil boring were performed for the project, however based on previous geotechnical explorations in the area and our observation of the natural granular soil conditions it is our opinion the designed 2,000 psf bearing capacity is a reasonable assumption pending additional compaction. Based on our observations it is our opinion all rubble fill and unsuitable organic rubble fill should be removed from within the proposed building area and replaced with suitable compacted engineered fill. The buried concrete floor slab can remain in place provided it is flat and is relatively in -tacked. However, all load bearing foundations should be placed beneath the existing floor slab on suitable compacted subgrade soils. Provided all load bearing foundations are placed on suitable compacted fill or compacted natural soil conditions, it is our opinion the design bearing capacity of 2,000 psf is appropriate. We recommend the subgrade soils and suitable fill material be compacted to 98% of a standard proctor ASTM D698. We understand the foundations were scheduled to be trenched using the existing soil as forms. IIowever, due to the granular nature of the soils encountered and the need for compactive effort /1)1ko;ld ,hldioll'1/1 "40 11:';JV[ M.PH/ • wcgip,loui - Olh(mllil[iunwidl'