1315 PACIFIC AVE 2018-01-01 MF Import

overezcavated areas pro��idcd thc contractor can achieve proper compaction. Suitablc on-sire soils for use as fill should not cnntain debris, organics, cxcessivc silUclay, and should not be more than 3 percer.t �bovc thc optimum moisturc conlcnt. Wc recommend using drier suitable fill soils and/or outwash soils. On-sitc soils must not bc uscd below planned foundations. Fill Pl�cemeot and Compaction Crilerir. Structural fill should bc mechanically compacted to a firtn, non-yielding condition. Structural fill should 'nc placcd in loose IifLc not exceeding 1 foot in thickness when compacted using heavy compaction equipmenL Loose lifts on [he order of 4 to 6 inches may be neccssary when hand compac�ion equipmeN is used. Each lifl should be conditioned [o thc proper moisture conlent and rompacted to the specified density before placing subsequenl lifls. Structural fill shoald be compactcd to the following criteria: • Structural fill placed bclow building foundations, floor slabs,and in pavement and sidcwalk areas (including utiliry trench backfill} should be compacted to at Icast 95 perceit of the MDD csiimatcd in accordancc with ASTM D1557. • Swctural fill placed against subgradc walls should be compac�ed to bctween 90 and 92 percent. We rccommcnd that GeoEnginecrs bc present during proof-rolling and/or probing of the exposed subgradc soils in building and pavemcnt areas, and placemcnt of swctural fill. We will evaluate the adcquacy of the subgrade soils and identify arcas necding funhcr work,perfortn in-place moisture-densiry tests in the fill to verify compliancc with the compaction specifications, and advise on any modifications to the procedures which may bc approprialc for thc prevailing conditions. R'cather Considcrations. Thc omsitc soils contain a sufticicnt percentnge of fines (silt) to be moisture scnsitivc. Whcn Ihc moislurc content of thcsc soils is morc than a few percent above thc optimum moisturc conlcN, thcsc soils bccomc muddy and unstable and operalion of equipment on these soils is difficult. Additionally, diswrbance of near surface soils should be expecled if catthw�ork is completcd during periods of wet weathcc During wet wcathcr,wc recommend that: • Thc ground surfacc in and around the work area shoald be sloped so that surface water is direc�ed aw�ay from the work arca. The ground sudace should bc gradcd such that areas of ponded wa�cr do not dcvclop. Mcasures should bc takcn by thc contractor to prcvcnt sudacc water from collccting in excavations and trenchcs. Mcasures should be implementcd to rcmove surface water from thc worA arca. • Slopcs with cxposcd soils should be covered with plaslic shecting or similar mcans. • The sile soils should not bc left un-compacted and cxposcd to moisture. Scaling the surGcial soils by rolling with a smooth-drum rollcr prior to periods of precipitation will reduce thc cxtent to which thcsc soils bccomc wct or unstablc. • Construction tratTic should be rcstrictcd to spccific arcas of the site, preferably areas that arc surfaccd with matcrials not susceptiblc to wct wcathcr disturb�ncc. • Conswction acti��itics should bc schcdulcd so that the lcngth of timc that soils are lefl cxposcd to moislure is mduced lo thc extent practical. RECOMMENDED ADDITIONAL GEOTECHNICAL SERVICES GwLnginecrs should be rctaincd to rcvicw thc projccl plans and spccifications ahen completc to confirm that our design rccommendations have bccn implemcnted as intended. lluring conswction, GeoGnginecrs should obscrvc the installation of the shoring system, review/collcct shoring monitoring data,cvaluate the suitability of the foundation and slab subgrades,observc installation r�a��,c� n��z-nni.ai Page 14 GtoEMwNetu� ✓��e n.?nox ��