Engineer Civil Engineering key terms

A field test that fills a standard cone with fresh concrete, removes the cone, and measures how far the sample settles, indicating workability and consistency of the mix.

The mass of water divided by the mass of cement in a concrete mix; a low ratio raises strength and durability while reducing workability.

Maintaining adequate moisture and temperature in placed concrete so cement hydration continues, developing design strength and reducing shrinkage cracking.

The longest chain of dependent activities through a project schedule; any delay on it postpones project completion, so it receives priority in schedule control.

The amount of time an activity can slip without delaying the project finish (total float) or its successor (free float).

A project control measure comparing budgeted value of work performed against actual cost and planned value to forecast cost and schedule performance.

A written, formally approved modification to contract scope, price, or schedule issued after the original agreement, requiring documentation and often cost justification.

Water content thresholds defining the liquid, plastic, and shrinkage states of fine-grained soil; they indicate plasticity and are used to classify clays and silts.

The difference between liquid limit and plastic limit water contents; a larger value means the soil remains plastic across a wider moisture range and is more compressible.

A borehole test driving a split spoon sampler with a hammer and counting blows per depth increment, giving a resistance index used for soil strength correlations.

The maximum pressure a foundation soil can support without shear failure or excessive settlement; it governs footing size and allowable design load.

Loss of soil shear strength when saturated loose sand is shaken and pore pressure rises until effective stress approaches zero, causing ground failure during earthquakes.

Total stress minus pore water pressure; it controls soil strength and compression because only intergranular contact stress resists deformation.

Gradual volume decrease of saturated clay as water drains from pores under sustained load, producing time-dependent settlement of structures.

The maximum load a structural member or material can carry before rupture or collapse, used as the basis for nominal resistance in design.

A multiplier applied to nominal loads in strength design to account for uncertainty and overload, paired with resistance factors to keep demand below capacity.

A design philosophy verifying that a structure satisfies both strength (safety against collapse) and serviceability (deflection, cracking) requirements under factored and unfactored loads.

The ability of a member or material to undergo large inelastic deformation before failure, giving warning and redistributing forces in seismic and overloaded conditions.

A structural system whose beams and columns are rigidly connected so joints transfer bending, providing lateral stiffness and drift resistance without diagonal bracing.

A vertical reinforced concrete or masonry wall designed to resist in-plane lateral forces, adding stiffness and strength to a building's lateral load system.

Concrete in which steel tendons are tensioned before or after casting to compress the section, controlling cracking and allowing longer spans.

A road structure of layered asphalt and granular base over subgrade that distributes wheel loads through progressively weaker layers and deforms elastically.

Selecting layer thicknesses so traffic loads do not exceed allowable stresses or strains, often using equivalent single axle loads and serviceability loss criteria.

The compacted natural soil beneath a pavement structure; its strength, measured by resilient modulus or CBR, strongly influences required pavement thickness.

The transverse slope built into a horizontal curve, raising the outer edge so vehicle weight helps resist centrifugal force and improve curve safety.

The length of roadway a driver can see ahead; stopping sight distance must exceed the distance needed to perceive, react, and brake before an obstacle.

A parabolic transition between two roadway grades that provides gradual change in slope and adequate sight distance over crests and valleys.

An empirical formula estimating peak runoff as the product of runoff coefficient, rainfall intensity, and drainage area, used for small urban catchments.

The travel time for water to flow from the most remote point of a catchment to its outlet, used to select rainfall intensity in peak flow estimates.

A storage facility that temporarily holds stormwater and releases it slowly, reducing peak downstream flows and limiting flooding and erosion.

The oxygen consumed by microorganisms decomposing organic matter in water, commonly measured over five days, indicating organic pollution and treatment performance.

A wastewater treatment process where aerated biomass consumes organic matter, followed by settling and return of sludge to maintain the microbial population.

The average period water remains in a treatment tank, equal to tank volume divided by flow rate; it sets contact time for settling and biological reactions.

A project delivery method where the owner contracts separately for design, then awards construction to the low bidder, with clear roles but limited builder input in design.