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7C <br /> Page 55 <br /> Mi#igation 11-2: The detailed, design-levei geotechnicai investigations required <br /> under Mifigafion 19-� shall include laboratflry analyses of all dredged materiaf and all materials <br /> proposed for use as fill. These analvses sha11 be sufficient to adequately estimate the rate and <br /> total amount of fii{ consolidation following compaction, and the resu[ting likelihood of differential <br /> settEement, especially in the areas af the reduced and reconfigured marina. Design of all filEs <br /> shall incorporate the results of these anafyses to minimize the destructive effects of future <br /> settlement, and the invesfigation shall set forth guidelines that address, at a minimum, the <br /> compositian of fill materiais, methods of fill placement, the required degree of fill compaction, <br /> and the {ayout of the subsurFace drainage systems needed to adequately dewater the filE. In <br /> addition, all improvements to be constructed on top of or within fills shall be designed in <br /> accordance with the recommendations of the detailed, design-level geotechnical investigafiians. <br /> Once a finai grading plan has been prepared and building loads determined, estimates of <br /> potential settlements for the grnund- and pile-supported structures, as wefl as for downdrag <br /> loads, shall be provided. Following corr�pletian of fills, settlement shall be monitored and <br /> improvement pfans shall be modified as necessary. <br /> The results of#he analyses of dredged material shall be included in any request <br /> ar appiication for disposal or reuse of dredged material. <br /> All recommendations contained in and derived from the detailed, design-level <br /> geotechnical investigations shall be incorporated in#o the canditions of approvaf for each <br /> structure or canstruction phase, with implementation enforced by#he City throughout the <br /> construction period. In general, #hese recammendations are expected to include, but not be <br /> limited to, the following provisions: <br /> 1. Suppart all project buildings on driven pifes. At this preliminary point in the <br /> geotechnical analysis, Treadwell & Rollo recommends precast, prestressed <br /> concrete piles with 100-ton capacity (12 inch) and 125-ton capacity (14 inch) <br /> at lengths af 75 to 90 feet and 80 to 95 feet, respec#ivefy. Perform pile load <br /> tests to evaivate the ultimate capacity and required length of the piles. <br /> 2. ifi settlements are found to be excessive, consider a surcharge program ta <br /> reduce the e�Fects of settlement, especially when filling in portions of the <br /> former marina. <br /> 3. Design ground fioor slabs to span between the pile caps and/or grade beams. <br /> �ifl shouid not be refied upon for support. <br /> 4. Use flexible connectians far utilities entering buildings in order to protect <br /> against breakage caused by differential settlement. <br /> 5. Hinge exteriar slabs and ramps attached to buildings in order fo protect <br /> against breakage caused by differential settfement between the buildings and <br /> the outside ground. <br /> 6. If settlements are found to be excessive, especially when filfing in portions of <br /> the existing and former marinas, consider a surcharge program to reduce the <br /> effects of sett[ement. Surcharging consists of placing excess fill in areas <br /> where settlements are a concem and leaving it in place a sufficient amount of <br /> fime to partially pre-consolidate the underlying compressible soil. <br /> AttylReso/Reso.1772 34 <br /> 121307 <br />