Maharashtra HSC General Civil Engineering (Bifocal) flashcards
Maharashtra HSC General Civil Engineering (Bifocal) · Build recall with a focused review session.
32 cards. Read the term and the definition here. The deck at the top of this page is optional.
- First-angle projection
- A projection method in which the object is placed between the observer and the plane of projection, so the top view appears below the front view.
- Representative fraction (RF)
- The ratio of drawing length to actual length, written as 1:50 or 1:100; it defines the scale used to prepare the drawing.
- Ellipse eccentricity
- The ratio of the distance from a point on the conic to the focus divided by its distance to the directrix; for an ellipse it is less than one.
- Nominal brick size
- A modular brick with actual size 190 × 90 × 90 mm, giving a nominal size of 200 × 100 × 100 mm after adding 10 mm mortar joints.
- English bond
- A brick bond with alternating courses of headers and stretchers; it is the strongest bond and is used for walls carrying heavy loads.
- Damp-proof course
- A layer of impervious material, usually 40–50 mm thick, laid at plinth level to stop moisture rising through the wall by capillary action.
- Height of instrument method
- A levelling method in which the reduced level of the line of collimation is found by adding the backsight to the benchmark level, then subtracting staff readings.
- Rise and fall method
- A levelling reduction method in which the difference between consecutive staff readings gives a rise or fall, checked by ΣBS − ΣFS = ΣRise − ΣFall.
- Two-peg test
- A field test for a level in which readings on two pegs at equal distances reveal the collimation error, which is then corrected by adjusting the cross-hair.
- Section modulus
- The ratio of the moment of inertia about the neutral axis to the distance to the extreme fibre, so bending stress equals bending moment divided by section modulus.
- Euler buckling load
- The critical axial load at which a slender column buckles, equal to π²EI divided by the square of the effective length.
- Poisson's ratio
- The ratio of lateral strain to longitudinal strain in a loaded member; it is about 0.3 for steel and about 0.2 for concrete.
- Water–cement ratio
- The mass of water divided by the mass of cement in a concrete mix; a lower ratio increases strength and durability but reduces workability.
- Characteristic strength
- The strength of concrete below which not more than 5% of test results fall; M20 concrete has a 28-day cube strength of 20 N/mm².
- Development length
- The embedded length of a reinforcing bar needed to develop its design stress in the concrete without the bar pulling out.
- Lami's theorem
- For three coplanar concurrent forces in equilibrium, each force divided by the sine of the angle opposite it is constant.
- Parallel-axis theorem
- The moment of inertia about any axis equals the moment of inertia about a parallel centroidal axis plus the area times the square of the distance between the axes.
- Angle of friction
- The angle whose tangent equals the coefficient of friction between two surfaces; the resultant reaction is inclined at this angle to the normal.
- Centre-line method
- A quantity surveying method that multiplies the total centre-line length of walls by width and depth for each item, suited to walls of uniform thickness.
- Prismoidal rule
- A volume formula using end areas and intermediate areas: V = h/3[(A1 + An) + 4(sum of even areas) + 2(sum of odd areas)].
- Contingency allowance
- A provision of about 3–5% of the estimated cost added to a detailed estimate to cover unforeseen items and price variations.
- Per capita demand
- The average quantity of water used per person per day; about 135 litres per head per day is taken for domestic supply in Indian towns.
- Chlorine demand
- The difference between the chlorine dose applied and the residual chlorine left after the contact period; it measures the chlorine consumed by impurities.
- Self-cleansing velocity
- The minimum flow velocity in a sewer, about 0.6–0.75 m/s, that prevents solids from settling and keeps the drain free from deposits.
- Superelevation
- The inward transverse slope given to a road curve, calculated as V²/(127R), to counteract centrifugal force; the maximum is 7% on plain terrain.
- Stopping sight distance
- The distance a driver needs to stop a vehicle after seeing an obstruction, equal to the lag distance plus the braking distance.
- CBR value
- The California Bearing Ratio, the ratio of the load required to penetrate a soil sample to that for standard crushed stone, used to design flexible pavement thickness.
- Critical path
- The longest path through a project network; its activities have zero total float and determine the minimum project duration.
- Total float
- The time by which an activity can be delayed without delaying the project completion; it equals latest start minus earliest start.
- Cost slope
- The additional cost per unit of time saved when an activity is crashed, computed as crash cost minus normal cost divided by normal time minus crash time.
- Excavation shoring
- Temporary support such as timber or sheet piling provided to the sides of a deep trench to prevent soil collapse and protect workers.
- Object snap (OSNAP)
- A CAD drafting aid that locks the cursor to precise geometric points such as endpoints, midpoints, centres, and intersections of existing objects.