PEC EPE Civil key terms

The maximum pressure a foundation soil can carry with an adequate margin of safety against shear failure, computed as ultimate bearing capacity divided by a factor of safety.

The theoretical pressure at which a supporting soil mass fails in shear beneath a loaded foundation, before any reduction by a factor of safety.

A classical formula expressing ultimate bearing capacity as a sum of cohesion, surcharge, and unit-weight terms, each multiplied by dimensionless bearing capacity factors.

Vertical downward movement of a structure or foundation caused by compression or deformation of the supporting soil under applied load.

Time-dependent volume reduction of a saturated soil as water is squeezed out of its voids under sustained loading, producing gradual settlement.

The intergranular stress carried by the soil skeleton, equal to total stress minus pore water pressure; it governs soil strength and compressibility.

The pressure of water filling the voids of a soil, which reduces the effective stress between particles and thus reduces shear strength.

Loss of shear strength in saturated loose granular soil when cyclic loading raises pore water pressure until effective stress approaches zero, so the soil behaves like a fluid.

An in-situ test in which a split-spoon sampler is driven by a drop hammer, and the blow count per depth interval is used to estimate soil density and strength.

An in-situ test that pushes an instrumented cone into the ground and records tip resistance and sleeve friction to classify soils and estimate strength parameters.

Water content boundaries that mark changes in the consistency of fine-grained soil, namely the liquid limit, plastic limit, and shrinkage limit.

The range of water content over which a soil remains plastic, calculated as the liquid limit minus the plastic limit.

Grouping of soils by grain size distribution and plasticity into standard categories such as the Unified Soil Classification System, to predict engineering behavior.

A footing that transfers structural load to soil at a relatively small depth, typically where the width exceeds the embedment depth, such as spread or strip footings.

A foundation element such as a pile or drilled shaft that carries load to deeper, stronger strata through skin friction and end bearing.

The total load a pile can support, comprising the sum of shaft friction along its length and end bearing at its base.

A ratio applied to a computed strength or capacity to provide margin against uncertainty, overload, and material variability in design.

The horizontal pressure that soil exerts on a retaining wall, varying between active, at-rest, and passive states depending on wall movement.

A structure built to hold back soil or other material and resist the lateral earth pressure it develops, maintaining a change in ground elevation.

Assessment of whether a natural or constructed soil slope can resist sliding failure, usually expressed as the ratio of resisting to driving forces.

Mechanical densification of soil by removing air voids, increasing unit weight and strength, and reducing future settlement.

A laboratory procedure that compacts soil at several water contents to determine the maximum dry unit weight and the corresponding optimum moisture content.

The capacity of a soil to transmit water through its interconnected voids, commonly expressed as a hydraulic conductivity coefficient.

The resistance of soil to internal sliding, governed by cohesion and friction and described by the Mohr-Coulomb failure criterion.

A model stating that shear failure occurs when shear stress reaches cohesion plus normal stress multiplied by the tangent of the friction angle.

The permanent, stationary weight of a structure and its fixed attachments, including beams, columns, slabs, finishes, and fixed equipment.

A variable load produced by occupancy and use, such as people, furniture, vehicles, or stored goods, treated as movable and statistically variable.

A prescribed arrangement of factored loads applied simultaneously in design, intended to represent the most unfavorable realistic loading condition.

A design philosophy that verifies a structure against defined conditions of safety and serviceability, such as strength, deflection, and durability.

A design condition requiring that a structure remain usable under normal service loads, controlling deflection, vibration, and cracking rather than collapse.

The displacement of a structural member from its original position under load, limited in design to prevent cracking, ponding, or occupant discomfort.

A composite material in which steel bars carry tensile forces while concrete resists compression, combining the strengths of both materials.

The thickness of concrete between the outer surface of embedded reinforcement and the nearest exposed concrete face, protecting steel from corrosion and fire.

The bending resistance of a member, determined by the internal moment capacity developed by concrete compression and steel tension.

Concrete in which internal compressive stress is induced by tensioned steel tendons before or after casting, reducing tensile stresses under service loads.

A vertical structural element designed to resist in-plane lateral forces from wind or earthquakes and transfer them to the foundation.

A structural frame whose beam-column connections resist rotation, providing lateral stiffness and strength without separate bracing.

The collection of structural elements, such as frames, walls, or bracing, that together resist horizontal forces and maintain building stability.

A coefficient describing the rate at which a fluid flows through a porous medium under a unit hydraulic gradient, dependent on both soil and fluid properties.