Civil Engineering Final Pre-Board Exam – Vocabulary Review

A set of vocabulary flashcards summarising key civil-engineering terms, formulas and concepts appearing in the pre-board examination notes.

Water-cement ratio (thin structures, wetting & drying)

Maximum recommended ratio by weight is 0.45 to limit permeability and cracking.

Water-cement ratio (mass concrete, wetting & drying)

Maximum recommended ratio by weight is 0.55 for durability of large sections.

Water-cement ratio (thin structures continuously under water)

Maximum recommended ratio by weight is 0.55 because continuous immersion reduces drying shrinkage risk.

Plutonic rock

Igneous rock formed by slow cooling of magma at considerable depth beneath Earth’s surface (e.g., granite).

Volcanic rock

Igneous rock produced by rapid cooling of lava at or near the Earth’s surface (e.g., basalt).

Strap footing

Foundation in which a cantilever (strap) beam connects two isolated footings to distribute eccentric loads.

Non-coplanar concurrent forces

Forces that intersect at a single point but whose lines of action lie in different planes.

Momentum

Product of a body’s mass and its velocity; a measure of motion (p = m v).

Shear modulus of elasticity (modulus of rigidity)

Ratio of shear stress to shear strain within the elastic limit of a material.

Bulk modulus of elasticity

Ratio of uniform pressure change to the resulting volumetric strain in a material.

Void ratio (e)

Volume of voids divided by volume of soil solids in a given soil mass.

Porosity (n)

Volume of voids divided by total volume of soil mass, often expressed as a percentage.

Degree of saturation (S)

Ratio of the volume of water in soil voids to the total volume of voids, expressed as a percentage.

Effective particle size (D10)

Particle diameter at which 10 % of a soil sample’s weight is finer; used in filter and drainage design.

Over-consolidation ratio (OCR)

Maximum past effective stress divided by present effective stress; OCR > 1 indicates over-consolidated clay.

Initial setting time of lime-pozzolana cement

Approximately 60 minutes before paste begins to lose plasticity.

Stainless steel (18-8)

Corrosion-resistant steel containing about 18 % chromium and 8 % nickel.

Portland cement raw-mix proportion

Typical manufacture uses about 63 % lime, 22 % silica, and 15 % alumina/iron/other oxides.

Asbestos cement

A brittle product that warps with humidity changes and loses strength when saturated with water.

Liquid & plastic limits

Consistency limits that exist primarily in clay soils and some silts, not in sands or gravels.

Crash time (project scheduling)

Shortest possible activity duration that minimises total construction cost when resources are expended.

Peak Hour Volume (PHV)

Maximum number of vehicles that pass a highway point during any 60 consecutive minutes within a day.

Parking lane

Auxiliary lane provided primarily for temporary vehicle storage along a roadway.

Sea-level distance (surveying)

Ground slope distance reduced to Earth’s mean sea-level using the average radius of curvature.

Level surface

Curved surface everywhere perpendicular to the direction of gravity and equidistant from Earth’s centre.

Line of sight (telescope)

Straight line that joins the intersection of cross-hairs to the optical centre of the objective lens.

Isogonic line

Imaginary line joining points of equal magnetic declination on Earth.

Agonic line

Imaginary line passing through points where magnetic declination is zero.

Daily (diurnal) magnetic variation

Slow swing of a compass needle that repeats approximately every 24 hours.

Incenter

Point inside a triangle where the internal angle bisectors meet; centre of the inscribed circle.

Natural (Napierian) logarithm base

The irrational constant e ≈ 2.718 281, base of hyperbolic or natural logarithms.

Characteristic of log 10(0.00078807)

−4 (the exponent of 10 immediately smaller than the number).

Modulus of elasticity (E)

Ratio of normal stress to corresponding axial strain within the elastic limit of a material.

Virtual work

Imagined work done by external forces during an infinitesimally small, compatible displacement of a system in equilibrium.

Silt particle size (minimum)

About 0.002 mm diameter according to common soil classification systems.

Oven-drying method

Most accurate laboratory technique for determining soil water content by mass difference after drying at 105 – 110 °C.

Bernoulli’s equation assumptions

Steady, incompressible, non-viscous flow along a streamline with no energy loss and only gravity as external force.

Total head

Sum of elevation (potential) head, velocity (kinetic) head, and pressure head of a flowing fluid.

High Reynolds number flow

Regime where inertial forces dominate and viscous forces are relatively unimportant (turbulent tendency).

Laminar pipe flow velocity ratio

For viscous laminar flow in a circular pipe, Vmax / Vavg = 2.0.

Shear stress distribution in laminar pipe flow

Zero at the pipe centre and increases linearly to a maximum at the wall.

Siphon

Closed conduit that conveys liquid from a higher reservoir to a lower one over an intermediate summit above the hydraulic grade line.

Friction factor (Darcy–Weisbach)

Dimensionless coefficient representing pipe wall resistance; relates head loss to velocity, length, and diameter.

Energy grade line (EGL)

Line joining piezometric heads plus velocity heads along a flow path; its slope equals head loss per unit length.

External distance of a simple curve

Radial distance from the point of intersection (PI) to the midpoint of the curve; used to compute chord lengths.

Superelevation

Transverse incline of a roadway, expressed as rise over width (m/m), to counteract centrifugal force on curves.

Centripetal acceleration rate (spiral)

Rate at which lateral acceleration increases along a transition curve; equals V³ / (C R L_s) in highway design.

Peak hour factor (transport)

Ratio of hourly traffic volume to the maximum rate of flow within the hour, indicating demand fluctuation.