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�EC-13-2004 09 :5� AM H. M. BOWER 828 T24 4643 P. 06 1925 Lskeview Tcnaa,prono MN --6-- � from any ass�tmptions indicated herein, then these recomm�t�dations may have to be reconsidered. • If the site is prep�red as autlin�l in#2 above, removing unsuitable soil, performing any furCher exCavations �s nece5sary, pl$cing controlled fill as necessary, then footings may be designed allowing no more th�an 2000 psf feundation bearing capacity (normai spread �ootings). This value is recommended an the basis of soil finnness �t ar near proposed or iikely footing leveis and recommended compaction level of eontrolled �11. This tak�s inta account shear failure patential near�eoting levels and the nature of deeper soil regarding sattlement�otential. Fill,as reyuired,shauld be placed,compacted,and tested as per the"Fil1 Placement"(#5) section foltowing. The abc�ve should provide a�actor of safety against f�undation failure of approxima.tsly 3. Over-all and differential settlements shauld be less th�n t3.S" and 0_25", respectivety. Ifa more refined estimate is required, further study and analysis would be necessary. if the site is graded to different levels th�n indicaCed �bove, if thE type of buildings propased chan.ge, or if soiis of a significantly diff�rent nature are discovered during excave�tions, the office of Intetstate Gec�t�chnical Engineering, inc should be eontacted for re-analysis and possibly revised recommendations. , It is not recornmended to place footings upon or over oz�ganic sail or any other unsuitable soil or to deviate from recommendations cc►ntained herein as excessivc differential and total settlement of the shucture could result. Building over the soft clay soil, without removal would result in a slow consoiidation over the years of several inches. A residentiai smaeture would be severely d�rnaged as a result and thc situatian coiild be life�threatening. it is not recommended to lower foundations, beyond their typica! levels,to minimize the oversi�ifig required. T'his is because even with the very soft clay removed, the clay left inplaee is toa soft to adequately bear direct footing cantact nar the stress of fnotings just above. These recommendafiions need a sufficient depth of�11 to allow spre�d o�load with depth to tolerable levels. 4. te ations: . ,As an altematave to dealing with problems noted abovc regazding depth af excavation, two types af aiternative foundations are possible here: (1)columns and pad.footings,and(2) anchor or driven piling.Reg$rding(i),this rvauld involve drilling foundation holes at regular intervals(eg, 8'-10')to suitable sail �evels (typically the deeper well consolidated clay soil), constructing cireular pad fou�dations at the b�ttom, and placing columns to normai foundation level. Grade beama�etween columns�uvould be necessary. Services af a s�ru�tural engine�r would also be neccssary ta anal�ze colum� loads and to design grade beams. COriStiUCtipn complicatians wauid .i�clude an installation that would be dif�'icult and some�what "blind"due to groundwater and the difficulty of keeping holes (up tc�20'+ deep) open until pads and eolumns are completed. The site soil being clay, wellpaint dcwatering dces not appear to be possible. To fully inv�tigate this possibility, preliminar,y structttra�l calculatians� should b� perfarmed to establish column ioads far various column spa.cings. Then, additional testing to determine bearing capacities and settlement estimates should be performed. This would