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Structural Concrete - Hassoun

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13.8 Footings under Biaxial Moment 479<br />

Mc<br />

Figure 13.28 Single footing subjected to eccentric loading: L = length of footing,<br />

B = width, and h = height.<br />

4. When the footing is moved a distance e from the axis of the column to produce uniform soil<br />

pressure under the footing: Maximum moment occurs at section n–n:<br />

M = M ′ − Hh and e = M P<br />

13.8 FOOTINGS UNDER BIAXIAL MOMENT<br />

In some cases, a footing may be subjected to an axial force and biaxial moments about its x and y<br />

axes; such a footing may be needed for a factory crane that rotates 360 ∘ . The footing then must be<br />

designed for the critical loading.<br />

Referring to Fig. 13.29, if the axial load P acts at a distance e x from the y axis and e y from<br />

the x axis, then<br />

M x = Pe y and M y = Pe x

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