8/2/2019 Combined Footig Design

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1. Calculate center of loads

1500 x = 1619 (3.7-x)

x= 1.92m

2. Calculate required area:

A req = [(1500+1619)+ Wf]/(qall)

Roughly

A req = [(1500+1619)* 1.1]/(200)

= 17.15 m2

Let B = 3.0 m

L = 5.8 m

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Now q ultimate = Pu/A actual

For ACI assume average load combinations factor = 1.25

q ultimate = (1500+1619)*1.25/(3.0x5.8) = 224.066

now draw shear force diagram

starting from left

224.066*3.0*.98 = 658.754

658.754-1500*1.25 = -1216.25

-1216.25+224.066*3.0*3.7 = 1270.886

1270.886 1619*1.25 = -752.863

-752.863 + 224.066*3.0*1.12 = 0.0012 = 0

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