A square footing is to carry a concentric wind-load related uplift force. The footing width, depth of water table and layer-wise soil properties are tabulated below. The footing base will be 400 mm thick, the square column that would transmit the uplift force will be 400 mm wide; both constructed with reinforced cement concrete with 25 kN/m unit weight. i. Construct a free body diagram assuming the failure surface to be vertical that runs along the footing perimeter and derive a relationship for the uplift force and average undrained shear strength. ii. Assuming the undrained shear strength to depend on effective vertical stress and overconsolidation ratio according to s,/o, = 0.25x OCR8 and the applicable factor of safety to be 2.5, find the ultimate and allowable uplift load that the footing is expected to carry. 16 9. 19 1.14