Question

The following data are available in designing a concrete foundation for 750kW diesel-gen set.

Over-all weight of gen set………………………. 28 600 kg

Bedplate Dimension………………………………. 7m x 2m

Over-all eff. Of generator………………………. 85%

Maximum depth of excavation………………. 6.5m

Sp. Wt. of foundation……………………………… 480 kg per BHp

Safe load bearing capacity of site……………. 30 Mtons per sq. m. with FS of 2

Density of concrete…………………………………. 2.4 Mtons per cu. M.

Top edges of foundation should not exceed 0.75m from the bedplate and foundation will taper only on the width side. What is the base dimension of the foundation?

1. 7m x 4.7m              b. 8.5m x 4.7m          c. 8.5m x 3.5m               d. 8.5m x 5.5m

Answer 1

Hello, the answer to the above question is option C, explanation of which is given in the photography below. After the explanation of this correct option, I have also explained that the chosen dimension of footing is peffectly safe with respect to bearing capacity. I would have also shown the other checks like "One-Way shear check" and " Punching Shear Stress" but data was not available in the question.

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