FE Civil key terms

Water-content thresholds that mark changes in the consistency of fine-grained soil, including the liquid limit, plastic limit, and shrinkage limit, used to classify clays and silts and predict their behavior.

The numerical difference between a soil's liquid limit and plastic limit, indicating the range of water content over which the soil behaves plastically; a large value signals high clay content and compressibility.

Mechanical densification of soil by removing air voids through rolling or tamping, usually measured against a moisture-density curve to achieve a specified dry unit weight in the field.

A laboratory procedure that compacts soil in a mold with a standard drop hammer to determine the maximum dry unit weight and optimum moisture content for a given compaction energy.

Time-dependent volume decrease of saturated fine-grained soil as water is squeezed out of its voids under sustained loading, often analyzed with e-log p curves and compression indices.

The intergranular stress carried by soil solids, equal to total stress minus pore water pressure; it governs shear strength, consolidation, and deformation behavior in saturated soils.

The maximum resistance of a soil mass to sliding along internal planes, commonly expressed through cohesion and friction angle from Mohr-Coulomb failure criteria and measured by direct shear or triaxial tests.

The maximum pressure a foundation soil can support without shear failure or excessive settlement, often computed with Terzaghi or Meyerhof equations using soil unit weight, cohesion, and friction angle.

Vertical downward movement of a structure's foundation caused by soil compression, including immediate elastic settlement and long-term consolidation settlement, which must stay within tolerable limits.

Loss of shear strength in loose saturated granular soil when earthquake shaking raises pore water pressure until effective stress approaches zero, causing soil to behave like a fluid.

Assessment of whether a natural or constructed slope can resist sliding, typically evaluated with factor of safety from limit equilibrium methods such as the method of slices.

A structure that holds back soil or other material and resists lateral earth pressures, which may be at-rest, active, or passive depending on wall movement and drainage conditions.

Horizontal stress exerted by soil on a wall or excavation support, classified as at-rest, active, or passive based on the amount and direction of wall movement relative to the soil.

Grouping of soils by engineering behavior using systems such as the Unified Soil Classification System, based on grain-size distribution, Atterberg limits, and sometimes organic content.

A measure of how densely a granular soil is packed relative to its loosest and densest possible states, often correlated with friction angle and liquefaction susceptibility.

A soil parameter describing the rate at which excess pore water pressure dissipates and consolidation progresses, used with drainage path length to estimate settlement over time.

A footing that transfers structural loads to soil at a relatively small depth below grade, commonly a spread footing or mat, designed using bearing capacity and settlement criteria.

A scheduling technique that identifies the longest sequence of dependent activities determining project duration, allowing planners to focus management attention on activities with zero float.

The amount of time an activity can be delayed without delaying the project completion date (total float) or its successor activities (free float).

A bar chart that displays scheduled activities along a time axis, showing start and finish dates and progress, often used alongside network schedules for communication and tracking.

A project control method comparing budgeted cost of work performed against actual cost and planned value to measure cost and schedule performance through indices and variances.

A written modification to a construction contract that alters scope, schedule, or price, typically requiring owner approval and proper documentation before the changed work proceeds.

A predetermined sum stated in a contract that a contractor pays the owner for each day of delay beyond the agreed completion date, intended to approximate actual damages.

A surety instrument submitted with a construction bid that guarantees the bidder will enter the contract and furnish required bonds if awarded the work.

A surety guarantee that protects the owner if a contractor fails to complete the work according to contract terms, allowing the surety to finish or compensate for the project.

A field test using a standard cone to measure the consistency and workability of fresh concrete; higher slump indicates a wetter, more flowable mix.

The mass ratio of water to cementitious material in a concrete mix, which strongly controls strength, durability, and workability; lower ratios generally produce stronger, less permeable concrete.

Maintaining adequate moisture and temperature in freshly placed concrete so cement hydration can continue, improving strength gain and durability and reducing cracking.

The ratio of a structure's or component's capacity to the applied demand, used in design to account for uncertainty in loads, material properties, and analysis methods.

A prescribed set of factored load cases applied simultaneously in design codes, such as dead plus live plus wind, to ensure members resist the most unfavorable credible loading.

The permanent, stationary weight of a structure's own materials and fixed components, such as beams, slabs, walls, and finishes, estimated from material densities and dimensions.

A nonpermanent load produced by occupancy and use, including people, furniture, vehicles, and movable equipment, specified by building codes based on occupancy type.

A graph showing the internal shear at each point along a beam, derived from loads and reactions, whose slope equals the applied distributed load and whose zero crossing often marks maximum moment.

A graph of internal bending moment along a member, whose slope equals the shear force and whose maximum and minimum values guide flexural reinforcement and section sizing.

The length of roadway ahead visible to a driver, including stopping sight distance for reacting and braking and passing sight distance for safe overtaking maneuvers.

The banking of a roadway cross section on curves, raising the outer edge to help offset centrifugal force and improve vehicle stability and comfort at design speeds.

A roadway alignment transition between two tangent directions, defined by radius, degree of curve, and tangent length, which must satisfy design speed and side-friction criteria.

The maximum rate of runoff at a point during or after a storm, estimated with methods such as the rational method or unit hydrograph for drainage and culvert design.

A rainfall-runoff technique estimating peak flow as the product of a runoff coefficient, rainfall intensity, and drainage area, typically applied to small urban watersheds.

A dimensionless ratio expressing the fraction of rainfall that becomes surface runoff, varying with land cover, soil type, and antecedent moisture conditions.

The time required for water to travel from the most hydraulically remote point of a watershed to the outlet, used to select rainfall intensity in peak-flow calculations.

The amount of dissolved oxygen consumed by microorganisms decomposing organic matter in a water sample over a set period, used to gauge organic pollution and treatment performance.

The mass concentration of particulate matter retained by a filter from a water sample, a key indicator of water quality and a common regulated parameter in discharge permits.

A sequence of physical, biological, and chemical processes that removes solids, organic matter, and nutrients from sewage before discharge or reuse, typically staged as primary, secondary, and tertiary.