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the exposed soil and maximize its shearing resistance strength. The over-excavated soil must be <br /> replaced with structural backfill up to foundations. This soil correction (over-excavation and <br /> structural backfill replacement) will provide foundation support material having uniform thickness <br /> and material character. This correction must be made according to recommendations in the <br /> OVER-EXCAVATION AND STRUCTURAL BACKFILL section of this report. <br /> RECOMMENDATIONS <br /> SITE PREPARATION <br /> Site preparation may require abandonment or relocation of buried utilities, if any exist or are <br /> encountered during construction. These utilities must be completely removed or capped or fully <br /> __. grouted. Excavations for these utilities must be backfilled with suitable compacted material <br /> according to the recommendations in the EXCAVATION AND EARTHWORK section of this report. <br /> Site preparation may require demolition and complete removal of all subsurface building <br /> - components, if any exist or are discovered during construction, such as foundations and foundation <br /> walls, floor slabs, and septic tank systems. Pavement in areas designated for new construction, if <br /> any exist or are discovered during construction, must be completely removed to expose voids and <br /> to prevent water entrapment in voids. <br /> _ FOUNDATION DESIGN AND CONSTRUCTION <br /> Building code requirements may include foundation design for seismic forces associated with <br /> earthquake motions. The project site is classified as Site Class D according to Table 1615.1.1 in <br /> the 2000 International Building Code. <br /> We recommend using shallow-depth foundations to support the building. Foundations must be <br /> spread footings. As discussed in the FOUNDATION SUPPORT section of this report, we <br /> recommend removing at least 2 feet of existing soil beneath foundations and replacing it with <br /> structural backfill up to foundations. <br /> We analyzed bearing capacity and load-settlement behavior for structural backfill. Our analysis <br /> -~ assumes maximum total settlement is on the order of one (1) inch and differential settlement is on <br /> the order of 3/4 of the total settlement. Spread footing foundations, bearing on at least 2 feet of <br /> structural backfill, can be bearing area sized using a maximum net allowable soil bearing pressure <br /> of 2000 pounds per square foot (psf). This bearing pressure is limited to foundations with <br /> continuous (strip) and isolated (square or circular) shapes up to 24 inches wide. The net allowable <br /> soil bearing pressure is the net pressure transferred from the foundation to underlying support soil. <br /> We strongly recommend careful observation and testing be made during foundation excavation by <br /> a Professional Engineer from our company. This can determine if exposed soil at foundation <br /> bearing grade is reliable to support foundations. If this soil is judged unreliable, the Engineer may <br /> recommend correcting this soil using an over-excavation and structural backfill method. This <br /> Allied Project 04049 7 July 27, 2004 <br />