Comprehensive definitions of technical terms from S to Z, covering structural mechanics, geotechnical engineering, hydrology, materials testing, and construction management.
The algebraic sum of all vertical forces acting on either side of a section of a beam. It tends to cause one part of the beam to slide vertically relative to the other part.
A field test to measure the consistency or workability of fresh concrete. It involves filling a conical mold (slump cone) in layers, rodding, and lifting it to measure the subsidence (slump) of the concrete.
The downward movement of a foundation due to the compression of the underlying soil under load. Excessive or differential settlement can cause structural damage.
A preliminary check for deflection control in beams and slabs. The ratio of the effective span to the effective depth should not exceed certain limiting values.
The transverse slope provided on horizontal curves to counteract the effect of centrifugal force, preventing vehicles from overturning or sliding outward.
A laboratory test to determine the relationship between moisture content and dry density of a soil. It establishes the Optimum Moisture Content (OMC) and Maximum Dry Density (MDD).
Transverse reinforcement (usually closed loops of steel bars) provided in beams and columns to resist shear forces and prevent buckling of longitudinal bars.
The maximum stress a material can withstand while being stretched or pulled before failing. Concrete has low tensile strength (approx. 10% of compressive), while steel has high tensile strength.
The tendency of matter to change in shape, area, and volume in response to a change in temperature. In long structures, this induces internal stresses if movement is restrained.
The twisting of a structural member when subjected to an applied torque (moment about the longitudinal axis). Causes shear stress distribution varying from zero at the center to max at the surface.
An electronic/optical instrument used for surveying and building construction. It combines an electronic theodolite (for angles) with an Electronic Distance Measurer (EDM) to measure slope distances.
The weight per unit volume of a material. Differentiated into Bulk Unit Weight (total weight/total volume), Dry Unit Weight (weight of solids/total volume), and Submerged Unit Weight.
The flow of wastewater through a sewer pipe below the capacity of the pipe. It is contrasted with "overflow" which occurs during surcharge conditions.
The ratio of the volume of voids (spaces filled with air/water) to the volume of solids in a soil mass. It is a primary indicator of soil density and compressibility.
A measure of a fluid's resistance to gradual deformation by shear stress or tensile stress. In road engineering, it determines the grade of bitumen used.
The mechanical process of removing entrapped air from fresh concrete to ensure complete consolidation around reinforcement and within formwork.
The ratio of the weight of water to the weight of cement in a concrete mix. It is the most critical factor determining the strength and durability of hardened concrete.
The upper surface of the zone of saturation where the pore water pressure equals atmospheric pressure. Below this level, soil pores are completely filled with water.
A two-way ribbed slab system with a grid of ribs formed by removable dome molds (void formers) placed on the underside. It reduces dead load while maintaining high stiffness.
The stress level at which a material begins to deform plastically. Prior to this point, deformation is elastic (recoverable). Beyond this point, permanent deformation occurs.
The theoretical curve on a compaction graph (Dry Density vs. Moisture Content) that represents the maximum possible dry density for any given moisture content, assuming the soil is fully saturated (100% saturation, no air voids).
The practice of dividing an earth dam into different zones of materials with specific properties (core, shell, filter, drain) to ensure stability, seepage control, and drainage.