2b - Formulas Used in the Design of Spread Footings

8/16/2019 2b - Formulas Used in the Design of Spread Footings

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DESIGN OF SPREAD FOOTINGS


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PUNCHING SHEAR (Two – way action)

(psi) '4 cc f v

shear For58.0

(MPa) 3

'cc

f v

τ 1


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WIDE BEAM SHEAR

(MPa) 6

'cc

f v

shear For58.0

(psi) '2cc

f v

FBD of efgh:

qU

τ2


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BENDING MOMENT

bendingFor90.0


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BENDING MOMENT

'59.01M 2u

c

y y f

f f bd

bendingFor90.0

Alternative equation


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)thickness(uniform 002.0min

65.0ksi4'05.085.01 c f

)thickness(variable 4.1

min y f

bmax 75.0

(MPa) 600

600'85.0

1 b

y y

c

f f

f

65.0MPa30'008.085.01 c f

(ksi) 000,87

000,87'85.0 1 b

y y

c

f f f


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Minimum length of embedment L d for reinforcing bars in tension :


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Development length for bond for compression bars is the largest of thefollowing:


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2b - Formulas Used in the Design of Spread Footings

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