ITEM 5 EXHIBITS A-H - Laserfiche WebLink

BLACK AVENUE RESIDENTIAL DEVELOPMENT 648-26-1 Page 8 5.1.3 Soil Corrosion Potential A preliminary soil corrosion screening was performed by JDH Corrosion Consultants based on the results of analytical tests on samples of the near-surface soil. In general, the JDH report concludes that the corrosion potential for buried concrete needs no special requirements. However, the corrosion potential for buried metallic structures, such as metal pipes, is considered corrosive. JDH recommends that special requirements for corrosion control be made to protect metal pipes. A more detailed discussion of the site corrosion evaluation is presented in Appendix C. 5.2 DESIGN-LEVEL GEOTECHNICAL INVESTIGATION The preliminary recommendations contained in this feasibility study were based on limited site development information and limited exploration. As site conditions may vary significantly between the small-diameter borings performed during this investigation, we also recommend that we be retained to 1) perform a design-level geotechnical investigation, once detailed site development plans are available; 2) to review the geotechnical aspects of the project structural, civil, and landscape plans and specifications, allowing sufficient time to provide the design team with any comments prior to issuing the plans for construction; and 3) be present to provide geotechnical observation and testing during earthwork and foundation construction. SECTION 6: EARTHWORK 6.1 ANTICIPATED EARTHWORK MEASURES On a preliminary basis, we recommend that existing foundations, slabs, and/or abandoned underground utilities be removed entirely and the resulting excavations backfilled with engineered fill. Additionally, native soils that are disturbed during demolition of the existing improvements should also be removed and replaced as engineered fill. Any existing undocumented fill encountered during grading should be over-excavated down to native soils within the proposed building footprints and 5 feet laterally beyond. On a preliminary basis and for conceptual planning and cost estimating, undocumented fill over-excavation on the order of 2½ feet below current site grades should be considered. On-site soils below the stripped layer appear to be suitable for use as fill at the site, provided they are determined to be suitable for re-use from an environmental viewpoint. Imported fill material for use as general fill should have a Plasticity Index of 15 or less and have at least 10 percent silt or clay fines to prevent sloughing or caving during construction. Existing asphalt and concrete materials can likely be pulverized and re-used as granular base material at the site; however, asphalt grindings should not be re-used beneath residential lots or building footprints. All fill as well as scarified surface soils in areas to receive fill or slabs-on-grade, and subgrade, and trench backfill, should be compacted to at least 90 percent relative compaction as determined by ASTM Test Designation D-1557, latest edition; and be at least 2 percent above optimum moisture. Aggregate materials should be compacted to at least 95 percent in pavement areas, and 90 percent in flatwork areas. The preliminary recommendations contained in this feasibility study were based on limited site The preliminary recommendations contained in this feasibility study were based on limited site development information and limited exploration. As site conditions may vary significantly development information and limited exploration. As site conditions may vary significantly diameter borings performed during this investigation, we also recommend diameter borings performed during this investigation, we also recommend level geotechnical investigation, once detailed site level geotechnical investigation, once detailed site development plans are available; 2) to review the geotechnical aspects of the project structural, development plans are available; 2) to review the geotechnical aspects of the project structural, civil, and landscape plans and specifications, allowing sufficient time to provide the design team civil, and landscape plans and specifications, allowing sufficient time to provide the design team with any comments prior to issuing the plans for construction; and 3) be present to provide with any comments prior to issuing the plans for construction; and 3) be present to provide geotechnical observation and testing during earthwork and foundation construction. geotechnical observation and testing during earthwork and foundation construction. ANTICIPATED EARTHWORK MEASURESANTICIPATED EARTHWORK MEASURES On a preliminary basis, we recommendOn a preliminary basis, we recommend that existing foundations, slabs, and/or abandoned that existing foundations, slabs, and/or abandoned underground utilities be removed entirely and the resulting excavations backfilled with underground utilities be removed entirely and the resulting excavations backfilled with engineered fill. Additionally, native soils that are disturbed during demolition of the existing engineered fill. Additionally, native soils that are disturbed during demolition of the existing improvements should also be removed and replaced as engineered fill. Any existing improvements should also be removed and replaced as engineered fill. Any existing undocumented fill encountered during grading should be overundocumented fill encountered during grading should be over within the proposed building footprints and 5 feet laterally beyond. On a preliminary basis and within the proposed building footprints and 5 feet laterally beyond. On a preliminary basis and conceptual planning and cost estimating, undocumented fill overconceptual planning and cost estimating, undocumented fill over feet below current site grades should be considered.feet below current site grades should be considered.