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76 Design Manuai for Segmenta�Retaizung WaIIs <br /> 2. Inclination of net foating loads is ignored in order to avoid excess conservativeness in � <br /> bearing capacity calculations and to be consistent with conventional ctice for rigid � <br /> gravity wall stn�ctures. The conservatism is created by the design assrzamption to ignore <br /> vefical component of Pe Similarly, corrections for footin� shape and length are also <br /> ignareei in this set of calculations. � <br /> � <br /> � <br /> 3. The effect of embedment depttz 8„�to the tap of the aggregate pad {footing) is a��aunted <br /> for as a d�ad load surcharge. The soil in front of the wall is assumed to h��ve no shear � <br /> resistance in bearing capacity analyses. The assurnption of a penmar�ent snrcharge mass ` <br /> must only be exercised if latge excavations in front of tSxe wall w.ill not occur for the life of � <br /> the shvcture.If excavatians are made they sizould�o ally be res�ricted to short excavation � <br /> Iengths in order to minirnize the potenti�I lass of toe suppart at the wall. � <br /> The factor of safety FS� with respect to bearing capacity failure of the foa�ndadoan soils can be � <br /> expressed as fallaws: e <br /> t�-¢1 s� � <br /> Fs,� ��,,/Qa i <br /> ¢ <br /> where Q,�represents the ultimate bearing capacity of the foundation soa�s and Q,the applied � <br /> 6earing stress. The magnitude of QA�xs calculated as�ollows: � <br /> I ,j� � <br /> � � 3ab �-� ���,'�����Za.�:(3� '�` � � <br /> �� � <br /> [Eq.4-20 � <br /> Q�,_ �,N + oS y B�N,.+ y,hi,,,,�1V <br /> ; <br /> � <br /> Ttzis is the classicaI bearing capacity eguation for a continuous footing jRef. 13�. The quantities N4, <br /> Nr and N, aze dimensionless be 'ng capaezty coefficients that can be obtanzed from a re 45 <br /> using the peak�richon angle of the foundatian soil �f. The quantity f �s the ec�uivaient fa►ting <br /> width due to eccentric footing loads and"zs calculated as: ', <br /> [Eq. 4-21] <br /> B�'=Bj.- 2e <br /> F�ccenEticity can � calculated by summir�g mornents about the center of the footing base. The <br /> center of rotat�on is taakken as the point Iocated a horizontal dis ce 'Wa ! 2 from the tae of the <br /> bottom �RW unit Moments are considered pasitive in a cat�rater-elockwise direction in this <br /> calculation set. Bccentricity is calculateci as: <br /> [Eq•4-22] <br /> e = (P, Ys+ Py Y - Ww�uJ�Wtii� <br /> where: <br /> [Eq.4-23� <br /> e�, = XW-0.5 tJV <br />