UPPSC AE Civil key terms

A design philosophy in which a structure is checked against defined collapse and serviceability conditions, using partial safety factors on loads and material strengths instead of a single global factor of safety.

A multiplier applied separately to loads and to material strengths in limit state design, accounting for uncertainty in load estimation and in material quality, with values differing for collapse and serviceability checks.

The strength value of concrete or steel below which not more than a stated small percentage of test results is expected to fall, usually taken as the mean minus a multiple of the standard deviation.

An older design approach that keeps computed stresses under service loads below permissible values, treating concrete and steel as linearly elastic and using a modular ratio to transform steel area into equivalent concrete area.

The ratio of the elastic modulus of steel to that of concrete, used in working stress design to convert reinforcement area into an equivalent concrete area so that a composite section can be analysed as one material.

A designation such as M25 expressing the characteristic cube compressive strength in newtons per square millimetre at 28 days, determined from standard 150 mm cubes tested under specified conditions.

The mass of water divided by the mass of cement in a concrete mix; it governs workability and, above the amount needed for full hydration, strongly controls porosity, strength and durability of the hardened concrete.

The ease with which fresh concrete can be mixed, placed, compacted and finished without segregation or bleeding, commonly assessed on site by the slump test or the compaction factor test.

Two defects of fresh concrete: segregation is the separation of coarse aggregate from the mortar, while bleeding is the upward migration of mixing water to the surface, both weakening the hardened mass.

The distance between the centres of supports, or the clear span plus effective depth, whichever is smaller, used in design calculations for bending moment and shear in beams and slabs.

The termination of some longitudinal bars where the bending moment diagram shows they are no longer required, subject to rules on anchorage length, development length and shear capacity at the cut-off point.

The embedded length of a bar needed to transfer its design force to the surrounding concrete by bond, calculated from bar diameter, design stress and bond stress so that the bar does not pull out.

The overlapping distance provided when bars are joined because stock lengths are insufficient, chosen at least equal to the development length with adjustments for tension, compression or seismic conditions.

Concrete in which internal compressive stresses are deliberately introduced, usually by tensioned high-strength steel, so that tensile stresses under service loads are reduced or eliminated, allowing longer spans and thinner sections.

A pre-stressing technique in which tendons are tensioned after the concrete has hardened, with the force transferred through end anchorages and often through ducts later filled with grout.

Time-dependent deformations of concrete: creep is slow strain increase under sustained stress, and shrinkage is volume reduction due to moisture loss, both causing deflection and loss of pre-stress.

The point in a cross-section through which a transverse load must pass to produce bending without twisting; for unsymmetrical sections it generally does not coincide with the centroid.

The second moment of area of a section about an axis, expressing how the area is distributed relative to that axis and thus its resistance to bending about it.

The moment of inertia of a section divided by the distance from the neutral axis to the extreme fibre, giving the section's bending resistance per unit of extreme fibre stress.

Sudden lateral failure of a slender member under compression when the applied load reaches a critical value depending on length, end conditions and flexural rigidity, rather than on material crushing strength.

The effective length of a compression member divided by its least radius of gyration; larger values reduce permissible compressive stress and make buckling the governing mode of failure.

The maximum pressure a foundation soil can sustain without shear failure or excessive settlement, usually expressed as a safe or allowable value after applying a factor of safety to the ultimate value.

A field test in which a split spoon sampler is driven into the ground by a standard drop hammer, and the number of blows for a specified penetration is recorded as an index of soil density and strength.

The gradual reduction in volume of a saturated soil under sustained load as pore water is squeezed out, producing time-dependent settlement that may continue for years in soft clays.

A rapid transition in open-channel flow from supercritical to subcritical state, accompanied by turbulence, energy loss and a rise in water surface, often used to dissipate energy below spillways.

A dimensionless ratio of inertial to gravitational forces in free-surface flow, used to classify flow as subcritical, critical or supercritical and to scale hydraulic models of channels and structures.

The flow condition at which the specific energy is minimum for a given discharge, occurring when the Froude number equals one and separating subcritical from supercritical regimes in a channel.

Irrigation terms describing water requirement: duty is the area irrigated per unit continuous discharge, while delta is the total depth of water applied to a crop over its base period.

The total water taken up by a crop and lost by transpiration plus that evaporated from the adjacent soil surface, forming the basis for estimating irrigation demand.

The time in days from sowing to harvest of a crop, used with the delta to compute the duty and to schedule canal supplies over the growing season.

A consistency test in which a standard needle is allowed to penetrate a bitumen sample under fixed load, time and temperature, with the measured depth in tenths of a millimetre indicating the binder grade.

The California Bearing Ratio, a measure of the resistance of a soil or pavement material to penetration compared with a standard crushed stone, used to design flexible pavement thickness.

A road structure whose layers transmit load mainly by grain-to-grain contact and which deforms slightly under traffic, typically comprising subgrade, sub-base, base and bituminous surfacing courses.

Network planning techniques for projects: CPM is deterministic and activity-oriented, focusing on critical path and float, while PERT is probabilistic and event-oriented, using three time estimates for uncertainty.

The longest-duration chain of dependent activities through a project network, which fixes the total project duration and has zero total float, so any delay on it delays completion.

The spare time available to an activity beyond its duration within the network, with total float being the delay possible without affecting project completion and free float without affecting successors.

Eleven obligations listed in Article 51A of the Indian Constitution, added by the 42nd Amendment, directing citizens to respect the Constitution, protect the environment and promote harmony, though not directly enforceable in courts.

Guidelines in Part IV of the Indian Constitution, from Articles 36 to 51, that direct the State towards social and economic welfare; they are non-justiciable but fundamental in governance.

The opening statement of the Indian Constitution declaring the source of authority to be the people and setting out the objectives of justice, liberty, equality and fraternity, amended once to add socialist and secular.

Two classes of Hindi vocabulary: tatsam words retain their original Sanskrit form unchanged, while tadbhav words are those that have evolved and changed phonetically from Sanskrit through Prakrit over time.

The phonetic combination of two adjacent sounds at a word boundary, producing a modified or merged form; Hindi grammar classifies these junctions by the sounds involved, such as vowel or consonant sandhi.

The compounding of two or more words into a single compound word in Hindi and Sanskrit, classified by the relation between components, such as tatpurush, dwandwa and bahuvrihi.