DDA JE Civil key terms

The maximum pressure a soil can carry at the base of a foundation without failing in shear or settling excessively. It is expressed in kN per square metre and governs footing size.

The allowable soil pressure obtained by dividing the ultimate bearing capacity by a factor of safety, usually 2.5 to 3. It also limits settlement to a permissible value.

The downward movement of a loaded foundation caused by compression of the supporting soil. Uniform settlement is tolerable; differential settlement causes cracking and structural distress.

A workability test in which fresh concrete is placed in a standard cone, the cone is lifted, and the drop in height is measured. It suits concrete of medium to high workability.

The ease with which fresh concrete can be mixed, placed and compacted without segregation. It is judged by slump, compaction factor or vee-bee time, and depends mainly on water content.

A laboratory test measuring the ratio of partially compacted to fully compacted concrete mass. It is more reliable than slump for dry, low-workability mixes used in pavements.

The mass of water divided by the mass of cement in a concrete mix. Lowering it raises strength and durability, but too little water harms workability; the usual range is 0.4 to 0.6.

Keeping concrete moist and at a favourable temperature after placing so cement hydration can continue. It develops strength and reduces shrinkage cracks; seven days is common, longer for severe exposure.

A designation such as M20 or M25 giving the characteristic compressive strength of 150 mm cubes at 28 days in N per square millimetre. The letter M stands for mix.

The internal turning effect at a section of a beam, equal to the algebraic sum of moments of all forces on one side of that section. It produces bending stresses across the depth.

The internal force acting along a section of a beam, equal to the algebraic sum of transverse forces on one side of the section. It produces diagonal shear stress.

The ratio of the moment of inertia of a section about the neutral axis to its distance to the extreme fibre. It measures bending strength of the section and is written as I divided by y.

The line within a bending section where longitudinal fibres neither stretch nor shorten, so bending stress is zero. It normally passes through the centroid of the cross-section.

The effective length of a compression member divided by its least radius of gyration. A higher value means a more slender column, lower buckling load and lower permissible stress.

The theoretical axial load at which a long, slender, perfectly straight column becomes unstable, given by pi squared E I divided by the square of effective length. It applies only to elastic buckling.

The distance between points of contraflexure in a column under load, used in place of actual length. It depends on end conditions, ranging from 0.5 times actual length for fixed-fixed ends.

Shear in a slab or footing acting on a full-width vertical section at a distance equal to the effective depth from the support or column face. It is checked like beam shear.

Shear around a concentrated load or column on a flat slab or footing, checked on a perimeter at half the effective depth from the load. It can cause sudden local failure.

A line on a map joining points of equal elevation above a datum. Closely spaced contours show steep ground; widely spaced ones show gentle slopes, which guides alignment and earthwork estimates.

A fixed, permanent point of known reduced level used as a reference for levelling. Temporary benchmarks are set up on site for the duration of a project.

The surveying operation of finding the difference in elevation between points using a level instrument and staff. It establishes reduced levels for earthwork, drainage and road profiles.

A method of computing the area under a curve by treating successive ordinate strips as trapeziums. It suits surveys where offsets are taken at equal intervals along a baseline.

A more accurate area formula that fits a parabola through three consecutive equally spaced ordinates. It requires an odd number of ordinates and gives better results than the trapezoidal rule.

A reasoning question type giving two or more premises and asking which conclusions follow logically from them. Conclusions must follow in every possible case, not merely seem plausible.

A technique for solving syllogisms by drawing circles for each class and checking whether a conclusion holds in every possible arrangement. It reduces errors when premises use words like some or all.

An unstated fact that must be true for a stated argument to hold. In verbal reasoning, the correct answer is essential to the argument, not merely supportive or likely.

A conclusion drawn from given information that is likely but not strictly guaranteed. Reasoning questions distinguish it from a definite conclusion, which must follow in every case.

A reasoning topic where letters or words are converted by a rule such as shifting positions or reversing order, and the candidate must apply the same rule to a new word.

A sequence of letters following a pattern of skips, reversals or alternating rules. The candidate identifies the rule and supplies the missing or next term.

Puzzle questions that describe family links through statements or a diagram, and ask how two people are related. Drawing a family tree with standard symbols prevents confusion.

Questions tracking a person moving through turns and distances to find final direction or shortest distance. A rough sketch with north at the top makes the answer easy to verify.

Basic freedoms guaranteed to citizens by Part III of the Indian Constitution, including equality, speech, life and personal liberty. They are enforceable through writs in the Supreme Court and High Courts.

Guidelines in Part IV of the Indian Constitution directing the state towards social and economic welfare. They are not enforceable in courts but are fundamental in governance.

A formal written order of a court commanding or restraining action, such as habeas corpus, mandamus, certiorari, prohibition or quo warranto. Articles 32 and 226 empower courts to issue them.

A seasonal reversal of wind direction bringing heavy rainfall to India, typically from June to September in the southwest monsoon. It dominates Indian agriculture and water availability.

An intense low-pressure storm forming over warm tropical seas with spiralling winds around a calm eye. In the Bay of Bengal and Arabian Sea it brings storm surges and heavy rain to coastal India.

A sentence construction in which the subject performs the action, as in the engineer approved the plan. It is usually clearer and more direct than the passive voice.

A construction in which the subject receives the action, formed with a form of be plus the past participle, as in the plan was approved. It is used when the doer is unknown or unimportant.

A fixed expression whose meaning cannot be worked out from its individual words, such as at the eleventh hour meaning very late. Idioms are tested through substitution and sentence usage.

A verb combined with a preposition or adverb that together carry a new meaning, such as put off meaning postpone. The particle cannot be understood from its literal sense.