Viva & Interview Question Bank

Working stress keeps stresses below allowable values under service loads; strength design multiplies loads by load factors and compares with the reduced nominal strength (φRn ≥ Σγ·Q). ACI 318 uses strength design.

One in which concrete reaches 0.003 strain at the same time as steel reaches yield. Under-reinforced sections are preferred so steel yields first and failure is ductile.

To prevent sudden brittle failure when the cracking moment exceeds the moment capacity of a very lightly reinforced section, and to control cracks.

Distance from the extreme compression fibre to the centroid of the tension steel.

To resist diagonal tension (shear), hold main bars in position and confine concrete.

The embedment needed for a bar to develop its yield stress through bond. It depends on bar size, fy, f′c, cover and confinement.

If the long span ÷ short span > 2 the slab bends mainly in one direction (one-way); otherwise it is two-way.

For bond, fire resistance and protection of steel against corrosion — e.g. ¾″ slabs, 1½″ beams and columns, 3″ footings on soil.

It ties walls together at the top of openings and improves earthquake resistance of load-bearing brick buildings.

A column is slender when kLu/r exceeds the code limit (about 22 for sway frames); slender columns need moment magnification.

One whose flanges and web are stocky enough to reach the full plastic moment without local buckling.

Sideways buckling and twisting of the compression flange of an unbraced beam; controlled by bracing length Lb.

Bearing bolts transfer load by shear and bearing against holes; slip-critical bolts rely on friction from pre-tension and are used where slip is not acceptable.

KL/r preferably ≤ 200 for compression members (≤ 300 for tension members other than rods).

To connect members at a joint in trusses and bracing, transferring forces between them.

Compaction is quick expulsion of air by mechanical energy; consolidation is slow expulsion of water from saturated clay under sustained load.

Maximum dry density and optimum moisture content for field compaction control.

σ′ = σ − u. It controls strength and deformation of soil (Terzaghi).

When upward seepage makes effective stress zero, so sand loses all strength (critical hydraulic gradient ≈ 1).

Shallow: depth ≤ width (isolated, strip, raft). Deep: piles and piers that transfer load to deeper strata.

Number of blows of a 63.5 kg hammer falling 760 mm to drive the split spoon the last 300 mm of a 450 mm drive.

To spread the load, improve weak soil, provide drainage and a level working base.

High-plasticity clay (high free swell) that swells and shrinks with moisture. Use deeper footings, under-reamed piles, moisture control or replacement.

Abrams' law: for workable, fully compacted concrete, strength depends inversely on w/c ratio.

To keep moisture for hydration, reduce shrinkage cracks and gain strength — at least 7 days for OPC.

Initial ≥ 45 minutes, final ≤ 10 hours (375 min in ASTM C191).

Increase in volume of moist sand (up to 20–30 %) — volume batching must be corrected.

Workability and consistency of fresh concrete; a shear or collapse slump shows a poor or very wet mix.

About M15 (15 MPa, ≈ 2,200 psi) when made and cured well.

Chemicals added to change properties — plasticisers, superplasticisers, retarders, accelerators, air-entrainers.

Work from whole to part, and locate each new point by at least two independent measurements.

Rise & fall gives a check on intermediate sights; HI is quicker but checks only the last reading.

A point of known reduced level used as reference.

Misclosure between the computed and the known end point, distributed by Bowditch or transit rule.

Horizontal and vertical angles and slope distance electronically; computes coordinates and levels.

Distance travelled during perception–reaction time plus braking distance.

To counteract centrifugal force on curves: e + f = V²/127R.

Flexible (asphalt) spreads load through layers; rigid (concrete) carries load by slab action.

Designing asphalt mixes — stability, flow, air voids and optimum bitumen content.

V = (1/n) R^(2/3) S^(1/2) (SI) for uniform open-channel flow.

Sudden rise of water when supercritical flow changes to subcritical, dissipating energy.

Typical design 30–50 gallons (135–225 litres) per capita per day for urban houses.

Settles solids and digests sludge anaerobically before effluent goes to a soakaway.

The longest chain of dependent activities with zero float; it fixes the project duration.

Time an activity can be delayed without delaying the project (total float) or the next activity (free float).

A method comparing planned value, earned value and actual cost to get SPI and CPI.

Bill of Quantities — items of work with quantities and rates, used for tendering and payments.

Wet volume × 1.54 (1.52–1.57).

About 13.5 bricks with mortar (≈ 500 per m³).

d²/162.2 kg per metre, with d in mm.

An interim payment certificate based on measured work done to date.

Beam sides 1–2 days, slab soffit 7 days (props 14), beam soffit 14–21 days in normal weather (OPC).

Levels, shuttering strength and joints, steel size/spacing/cover, chairs, laps, conduits, cleanliness, curing plan and concrete supply.

Differential settlement, thermal movement or shrinkage; check foundation, drainage and the crack pattern before repair.

Approved materials, correct batching, slump checks, cube/cylinder samples, proper compaction and curing.

Give a sincere answer — interest in seeing designs become real, solving site problems and working with people.

Name what you can actually use: AutoCAD, ETABS, SAFE, Primavera, Excel — and one project where you used it.