Maharashtra HSC Construction Technology (Vocational) key terms

The maximum pressure a soil can carry at the base of a foundation without failing in shear or settling excessively. It decides the size and type of footing needed for a structure.

Mechanical removal of air voids from soil or concrete by rolling, tamping or vibrating, which increases density and strength and reduces future settlement. Measured on site by the standard Proctor test in the laboratory.

The finished floor height of a building measured above ground level, usually kept 300 to 600 mm above the surrounding ground to stop rainwater entry and protect walls from dampness.

A continuous moisture-resistant layer, such as bitumen felt or cement mortar with waterproofing compound, laid at plinth level across all walls to stop rising damp from the ground reaching the walls above.

A continuous concrete base running under a load-bearing wall, wider than the wall, which spreads the wall load over a larger soil area. Used where soil bearing capacity is moderate and walls carry the load.

A site test of fresh concrete workability in which a standard cone is filled, lifted and the drop in height measured. A higher slump means a wetter, more workable mix.

The mass of water divided by the mass of cement in a concrete mix. Lower values give stronger, denser concrete but reduce workability, so the ratio is fixed by the design mix.

Keeping concrete moist and at a suitable temperature after placing so cement hydration continues. Curing for at least seven days for ordinary cement develops design strength and reduces surface cracking.

A designation such as M20 or M25 giving the characteristic compressive strength in newtons per square millimetre at 28 days, tested on 150 mm cubes. It guides mix design and structural use.

A concrete mix specified by volume proportions of cement, sand and coarse aggregate, such as 1:2:4, rather than by designed weights. Used for small or non-critical work.

Steel bars or mesh placed in concrete to resist tensile and shear forces that concrete alone cannot carry. Bars must have correct cover, spacing and laps as shown on the bar bending schedule.

The thickness of concrete between the outer surface of the reinforcement and the nearest concrete face. It protects steel from corrosion and fire and must match the drawing specification.

A table listing each reinforcement bar's mark, diameter, shape, cut length, number and bending details, used to cut and fix steel and to estimate quantities on site.

The systematic measurement of work items from drawings, in the units used by the schedule of rates, such as cubic metres of concrete or square metres of plaster, to prepare an estimate.

An estimating method in which the total centre-line length of walls is measured once and multiplied by width and height, with deductions at junctions, giving fast results for similar wall sections.

A summary sheet that multiplies each measured quantity by its rate and totals the amounts, then adds contingency and overheads to give the estimated project cost.

The fixed ratio between a distance on a drawing and the real distance it represents, for example 1:100 where one drawing unit equals one hundred real units. Every drawing states its scale.

A drawing showing a building or site as seen from directly above, cut at a stated level, giving room sizes, wall thicknesses, openings and layout. It is the base drawing for all other views.

A drawing showing the external face of a building viewed horizontally from one side, giving heights, levels, openings and finishes. It is read together with the plan.

A drawing showing the building cut vertically to reveal internal construction, floor levels, foundation depth and roof detail. It is used to check heights and construction build-up.

A fixed point of known reduced level, marked on a permanent object, from which all other levels on a site are measured. Levels are transferred from it by levelling instruments.

The height of a point above a chosen datum, usually mean sea level, calculated from staff readings in leveling. Written as RL and used to set foundations and finished floor heights.

A levelling instrument with a fixed telescope held horizontal by a spirit level, mounted on a tripod. It reads staffs to find height differences between points on site.

The first staff reading taken on a point of known level after setting up the level, used to calculate the height of the instrument. The last reading before moving the instrument is a foresight.

A line on a map joining points of equal elevation, so its spacing shows ground steepness: close lines mean steep ground, wide spacing means flat ground. Used in site selection and road alignment.

An electronic surveying instrument combining a theodolite with distance measurement and onboard computing, recording angles and distances to give coordinates and levels of points directly.

A temporary working platform of standards, ledgers and boards erected around a building so workers can reach heights safely. It must be braced, tied to the structure and fitted with guardrails.

Temporary moulds of timber, plywood or steel that hold fresh concrete in shape until it sets. Good formwork is tight, strong and treated so it strips cleanly without damaging the concrete.

Temporary support given to an unsafe or partly built structure, or to the sides of a deep excavation, to prevent collapse during construction work.

Wearable safety gear such as helmet, safety shoes, gloves, goggles and harness issued to workers to reduce injury risk. It is the last line of defence after hazards are controlled.

A hard hat with a chin strap worn on site to protect the head from falling objects and knocks. It must be undamaged, correctly fitted and replaced after a heavy impact.

A written authorisation issued before high-risk work such as hot work, confined-space entry or excavation near services, recording the hazards, controls and the person in charge.

A U-shaped fitting holding a water seal that stops sewer gases entering a building while letting wastewater pass. The seal depth is normally 50 to 75 mm and needs venting.

The vertical pipe that carries sewage from water closets down to the drainage line. It is vented at the top and fitted with a trap at each fixture connection to keep gases out.

An accessible chamber on a drainage line where pipes change direction, size or gradient, allowing rodding and inspection. It has a removable cover at ground level and a benched channel.

Connecting exposed metal parts of electrical installations to the ground through a low-resistance path so fault current trips protection and does not shock a person touching the metal.

Collecting and storing rainwater from roofs or paved areas for reuse or for recharging groundwater, reducing dependence on supplied water and site runoff.

A priced document listing measured work items with descriptions and quantities, forming part of a tender. Contractors quote rates against it and it supports payment and variation claims.

A formal offer from a contractor to carry out specified work at stated rates within a stated time. Tenders are invited against drawings, specifications and a bill of quantities.

A written instruction from the engineer or employer to the contractor authorising a specific task or variation, with scope, time and payment terms, forming a record for billing.