Foundation Design interview questions

1. A.total settlement 50 mm for isolated footings on sand and 75 mm on clay, 75 and 100 mm for rafts, with angular distortion capped at 1/300 for steel frames
2. B.net ultimate bearing capacity divided by a factor of safety of 2.5 to 3, with the overburden pressure added back to give the gross safe value
3. C.smaller of the safe bearing capacity from shear failure and the pressure that keeps settlement within IS 1904 limits, so settlement often governs on sand and clay
4. D.downward drag on a pile shaft when surrounding fill or soft clay consolidates after installation, added to the pile load or avoided by bitumen coating or sleeving

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1. A.Safe bearing capacity
2. B.Terzaghi bearing capacity equation
3. C.Pile load test
4. D.Under-reamed pile

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1. A.Safe bearing capacity — bored cast in-situ pile with one or two bulbs about 2.5 times the stem diameter, anchoring below the 3 to 4 m active zone of expansive black cotton soil
2. B.Safe bearing capacity — qu = c Nc + γ D Nq + 0.5 γ B Nγ for a strip footing, with 1.3 on the cohesion term and 0.8 on the width term for square footings
3. C.Safe bearing capacity — chosen when isolated footings would cover more than about half the plan area or differential settlement must be tied together, analysed on Winkler soil springs from the modulus of subgrade reaction
4. D.Safe bearing capacity — net ultimate bearing capacity divided by a factor of safety of 2.5 to 3, with the overburden pressure added back to give the gross safe value

Answer + AI explanation with Pro

1. A.smaller of the safe bearing capacity from shear failure and the pressure that keeps settlement within IS 1904 limits, so settlement often governs on sand and clay
2. B.chosen when isolated footings would cover more than about half the plan area or differential settlement must be tied together, analysed on Winkler soil springs from the modulus of subgrade reaction
3. C.downward drag on a pile shaft when surrounding fill or soft clay consolidates after installation, added to the pile load or avoided by bitumen coating or sleeving
4. D.bored cast in-situ pile with one or two bulbs about 2.5 times the stem diameter, anchoring below the 3 to 4 m active zone of expansive black cotton soil

Answer + AI explanation with Pro

1. A.Raft foundation selection
2. B.Allowable bearing pressure
3. C.Under-reamed pile
4. D.Safe bearing capacity

Answer + AI explanation with Pro

1. A.Allowable bearing pressure — IS 6403 reduces c to two-thirds and tan φ to two-thirds for loose soils with φ below 28 degrees, interpolating up to 36 degrees where general shear applies
2. B.Allowable bearing pressure — bored cast in-situ pile with one or two bulbs about 2.5 times the stem diameter, anchoring below the 3 to 4 m active zone of expansive black cotton soil
3. C.Allowable bearing pressure — smaller of the safe bearing capacity from shear failure and the pressure that keeps settlement within IS 1904 limits, so settlement often governs on sand and clay
4. D.Allowable bearing pressure — net ultimate bearing capacity divided by a factor of safety of 2.5 to 3, with the overburden pressure added back to give the gross safe value

Answer + AI explanation with Pro

1. A.qu = c Nc + γ D Nq + 0.5 γ B Nγ for a strip footing, with 1.3 on the cohesion term and 0.8 on the width term for square footings
2. B.bored cast in-situ pile with one or two bulbs about 2.5 times the stem diameter, anchoring below the 3 to 4 m active zone of expansive black cotton soil
3. C.total settlement 50 mm for isolated footings on sand and 75 mm on clay, 75 and 100 mm for rafts, with angular distortion capped at 1/300 for steel frames
4. D.net ultimate bearing capacity divided by a factor of safety of 2.5 to 3, with the overburden pressure added back to give the gross safe value

Answer + AI explanation with Pro

1. A.IS 1904 settlement limits
2. B.Terzaghi bearing capacity equation
3. C.Negative skin friction
4. D.Under-reamed pile

Answer + AI explanation with Pro

1. A.Terzaghi bearing capacity equation — downward drag on a pile shaft when surrounding fill or soft clay consolidates after installation, added to the pile load or avoided by bitumen coating or sleeving
2. B.Terzaghi bearing capacity equation — smaller of the safe bearing capacity from shear failure and the pressure that keeps settlement within IS 1904 limits, so settlement often governs on sand and clay
3. C.Terzaghi bearing capacity equation — IS 2911 Part 4 loads an initial test pile to 2.5 times design load and routine piles to 1.5 times, with safe load taken as two-thirds of that at 12 mm settlement
4. D.Terzaghi bearing capacity equation — qu = c Nc + γ D Nq + 0.5 γ B Nγ for a strip footing, with 1.3 on the cohesion term and 0.8 on the width term for square footings

Answer + AI explanation with Pro

1. A.smaller of the safe bearing capacity from shear failure and the pressure that keeps settlement within IS 1904 limits, so settlement often governs on sand and clay
2. B.IS 6403 reduces c to two-thirds and tan φ to two-thirds for loose soils with φ below 28 degrees, interpolating up to 36 degrees where general shear applies
3. C.downward drag on a pile shaft when surrounding fill or soft clay consolidates after installation, added to the pile load or avoided by bitumen coating or sleeving
4. D.chosen when isolated footings would cover more than about half the plan area or differential settlement must be tied together, analysed on Winkler soil springs from the modulus of subgrade reaction

Answer + AI explanation with Pro

1. A.Safe bearing capacity
2. B.Terzaghi bearing capacity equation
3. C.Pile load test
4. D.Local shear correction

Answer + AI explanation with Pro

1. A.Local shear correction — IS 2911 Part 4 loads an initial test pile to 2.5 times design load and routine piles to 1.5 times, with safe load taken as two-thirds of that at 12 mm settlement
2. B.Local shear correction — total settlement 50 mm for isolated footings on sand and 75 mm on clay, 75 and 100 mm for rafts, with angular distortion capped at 1/300 for steel frames
3. C.Local shear correction — smaller of the safe bearing capacity from shear failure and the pressure that keeps settlement within IS 1904 limits, so settlement often governs on sand and clay
4. D.Local shear correction — IS 6403 reduces c to two-thirds and tan φ to two-thirds for loose soils with φ below 28 degrees, interpolating up to 36 degrees where general shear applies

Answer + AI explanation with Pro

1. A.net ultimate bearing capacity divided by a factor of safety of 2.5 to 3, with the overburden pressure added back to give the gross safe value
2. B.chosen when isolated footings would cover more than about half the plan area or differential settlement must be tied together, analysed on Winkler soil springs from the modulus of subgrade reaction
3. C.smaller of the safe bearing capacity from shear failure and the pressure that keeps settlement within IS 1904 limits, so settlement often governs on sand and clay
4. D.total settlement 50 mm for isolated footings on sand and 75 mm on clay, 75 and 100 mm for rafts, with angular distortion capped at 1/300 for steel frames

Answer + AI explanation with Pro

1. A.IS 1904 settlement limits
2. B.Under-reamed pile
3. C.Raft foundation selection
4. D.Terzaghi bearing capacity equation

Answer + AI explanation with Pro

1. A.IS 1904 settlement limits — IS 6403 reduces c to two-thirds and tan φ to two-thirds for loose soils with φ below 28 degrees, interpolating up to 36 degrees where general shear applies
2. B.IS 1904 settlement limits — downward drag on a pile shaft when surrounding fill or soft clay consolidates after installation, added to the pile load or avoided by bitumen coating or sleeving
3. C.IS 1904 settlement limits — IS 2911 Part 4 loads an initial test pile to 2.5 times design load and routine piles to 1.5 times, with safe load taken as two-thirds of that at 12 mm settlement
4. D.IS 1904 settlement limits — total settlement 50 mm for isolated footings on sand and 75 mm on clay, 75 and 100 mm for rafts, with angular distortion capped at 1/300 for steel frames

Answer + AI explanation with Pro

1. A.smaller of the safe bearing capacity from shear failure and the pressure that keeps settlement within IS 1904 limits, so settlement often governs on sand and clay
2. B.IS 6403 reduces c to two-thirds and tan φ to two-thirds for loose soils with φ below 28 degrees, interpolating up to 36 degrees where general shear applies
3. C.downward drag on a pile shaft when surrounding fill or soft clay consolidates after installation, added to the pile load or avoided by bitumen coating or sleeving
4. D.IS 2911 Part 4 loads an initial test pile to 2.5 times design load and routine piles to 1.5 times, with safe load taken as two-thirds of that at 12 mm settlement

Answer + AI explanation with Pro

1. A.Under-reamed pile
2. B.Negative skin friction
3. C.Local shear correction
4. D.Pile load test

Answer + AI explanation with Pro

1. A.Pile load test — downward drag on a pile shaft when surrounding fill or soft clay consolidates after installation, added to the pile load or avoided by bitumen coating or sleeving
2. B.Pile load test — IS 6403 reduces c to two-thirds and tan φ to two-thirds for loose soils with φ below 28 degrees, interpolating up to 36 degrees where general shear applies
3. C.Pile load test — qu = c Nc + γ D Nq + 0.5 γ B Nγ for a strip footing, with 1.3 on the cohesion term and 0.8 on the width term for square footings
4. D.Pile load test — IS 2911 Part 4 loads an initial test pile to 2.5 times design load and routine piles to 1.5 times, with safe load taken as two-thirds of that at 12 mm settlement

Answer + AI explanation with Pro

1. A.smaller of the safe bearing capacity from shear failure and the pressure that keeps settlement within IS 1904 limits, so settlement often governs on sand and clay
2. B.downward drag on a pile shaft when surrounding fill or soft clay consolidates after installation, added to the pile load or avoided by bitumen coating or sleeving
3. C.chosen when isolated footings would cover more than about half the plan area or differential settlement must be tied together, analysed on Winkler soil springs from the modulus of subgrade reaction
4. D.total settlement 50 mm for isolated footings on sand and 75 mm on clay, 75 and 100 mm for rafts, with angular distortion capped at 1/300 for steel frames

Answer + AI explanation with Pro

1. A.Negative skin friction
2. B.Safe bearing capacity
3. C.Terzaghi bearing capacity equation
4. D.Raft foundation selection

Answer + AI explanation with Pro

1. A.Negative skin friction — total settlement 50 mm for isolated footings on sand and 75 mm on clay, 75 and 100 mm for rafts, with angular distortion capped at 1/300 for steel frames
2. B.Negative skin friction — net ultimate bearing capacity divided by a factor of safety of 2.5 to 3, with the overburden pressure added back to give the gross safe value
3. C.Negative skin friction — downward drag on a pile shaft when surrounding fill or soft clay consolidates after installation, added to the pile load or avoided by bitumen coating or sleeving
4. D.Negative skin friction — bored cast in-situ pile with one or two bulbs about 2.5 times the stem diameter, anchoring below the 3 to 4 m active zone of expansive black cotton soil

Answer + AI explanation with Pro

1. A.bored cast in-situ pile with one or two bulbs about 2.5 times the stem diameter, anchoring below the 3 to 4 m active zone of expansive black cotton soil
2. B.IS 6403 reduces c to two-thirds and tan φ to two-thirds for loose soils with φ below 28 degrees, interpolating up to 36 degrees where general shear applies
3. C.IS 2911 Part 4 loads an initial test pile to 2.5 times design load and routine piles to 1.5 times, with safe load taken as two-thirds of that at 12 mm settlement
4. D.downward drag on a pile shaft when surrounding fill or soft clay consolidates after installation, added to the pile load or avoided by bitumen coating or sleeving

Answer + AI explanation with Pro

1. A.Raft foundation selection
2. B.Pile load test
3. C.IS 1904 settlement limits
4. D.Under-reamed pile

Answer + AI explanation with Pro

1. A.Under-reamed pile — smaller of the safe bearing capacity from shear failure and the pressure that keeps settlement within IS 1904 limits, so settlement often governs on sand and clay
2. B.Under-reamed pile — chosen when isolated footings would cover more than about half the plan area or differential settlement must be tied together, analysed on Winkler soil springs from the modulus of subgrade reaction
3. C.Under-reamed pile — bored cast in-situ pile with one or two bulbs about 2.5 times the stem diameter, anchoring below the 3 to 4 m active zone of expansive black cotton soil
4. D.Under-reamed pile — IS 6403 reduces c to two-thirds and tan φ to two-thirds for loose soils with φ below 28 degrees, interpolating up to 36 degrees where general shear applies

Answer + AI explanation with Pro

1. A.qu = c Nc + γ D Nq + 0.5 γ B Nγ for a strip footing, with 1.3 on the cohesion term and 0.8 on the width term for square footings
2. B.total settlement 50 mm for isolated footings on sand and 75 mm on clay, 75 and 100 mm for rafts, with angular distortion capped at 1/300 for steel frames
3. C.IS 2911 Part 4 loads an initial test pile to 2.5 times design load and routine piles to 1.5 times, with safe load taken as two-thirds of that at 12 mm settlement
4. D.chosen when isolated footings would cover more than about half the plan area or differential settlement must be tied together, analysed on Winkler soil springs from the modulus of subgrade reaction

Answer + AI explanation with Pro

1. A.Local shear correction
2. B.Raft foundation selection
3. C.Negative skin friction
4. D.Safe bearing capacity

Answer + AI explanation with Pro

1. A.Raft foundation selection — IS 2911 Part 4 loads an initial test pile to 2.5 times design load and routine piles to 1.5 times, with safe load taken as two-thirds of that at 12 mm settlement
2. B.Raft foundation selection — chosen when isolated footings would cover more than about half the plan area or differential settlement must be tied together, analysed on Winkler soil springs from the modulus of subgrade reaction
3. C.Raft foundation selection — downward drag on a pile shaft when surrounding fill or soft clay consolidates after installation, added to the pile load or avoided by bitumen coating or sleeving
4. D.Raft foundation selection — total settlement 50 mm for isolated footings on sand and 75 mm on clay, 75 and 100 mm for rafts, with angular distortion capped at 1/300 for steel frames

Answer + AI explanation with Pro