Common Engineering Terms Glossary


Structural engineering can be difficult enough without industry jargon making it difficult anyone to know what you're talking about.

We try and make ClearCalcs as simple and straightforward as possible, but even we sometimes fall victim to assuming knowledge. With that in mind, we've put together a list of common engineering terms you'll see us use throughout the engineering software:


A structural member (typically horizontal) carrying loads along its length. Based on the beam's supports, it can be simple, continuous, or cantilevered. Depending on a beam's purpose, it may be known by a variety of names, including rafter, purlin, bearer, and joist (we've included definitions of these below). All of these can be designed using our online free beam calculator.


Bearers are beams carrying loads across larger spans coming from joists. Bearers typically run along the direction of the longest wall, with joists placed perpendicularly above.

An example of a simply supported floor beam


A beam-column is a member subject to axial and lateral/horizontal loads (i.e. one that is acting as a beam with a load along its length, as well as acting like a column with an axial load on its shorter side/s). A good example of a beam-column is a beam in a moment or braced frame that is subject to both gravity and lateral loads (e.g. dead and wind loads).

Bi-Axial Load

Bi-axial loads are those where the load is acting in two directions (axes) at once. An example is where a column is loaded eccentrically along its Y and X axis simultaneously.

Bill of Quantities (BOQ)

A list of the quantities of each material/component being used in the engineering design. This can be used by the builder/estimator to help cost the job, and see at a glance what is required.

Cantilever (also known as Propped)

The cantilever refers to the length of a beam that is not supported. A beam can be cantilevered (i.e. not supported) at one or both ends depending on the support locations.

Example of a cantilever propped at the midspan. The beam length to the right is known as the cantilevered end.
Example of a fixed cantilevered beam. In this example, the entire length of the beam is cantilevered from the support.


A structural member (typically vertical) that transmits and supports a structure's weight and loads through compression.

Dead Load (also known as Permanent Load)

Intrinsic or permanent loads acting upon a structure. Examples of constant loads such as these might be the self weight of the structure, as well as immovable fixtures such as walls.

Deflection (also known as Displacement)

Describes the degree to which a structural element moves or displaces from its original position due to load.

Example deflection curve of a simply supported beam with a uniform distributed load


A footing refers to an individual shallow foundation unit, commonly made out of brick, masonry or concrete. It is positioned below the base of a wall or column to distribute the load over a larger area. They are usually part of larger foundation system.


A foundation is the part of a structure which provides support by transmitting the structural loads directly to the underlying soil or rock. The underlying deposit must have a sufficient bearing capacity and settlement characteristics.

Shallow foundations transfer load to near surface deposits, and have a width much greater than their depth. Deep foundations transfer loads to deposits further beneath the surface, and their depth is much greater than their width.


Example of a Gable Roof - Source: Wikipedia

A gable is the triangular upper part of a wall between intersecting sloping roof pitches.

Girder Truss

A girder truss typically has a long straight design, traditionally designed to be very rigid and strong. The main role is to support other roof support elements such as rafters, purlins and regular trusses.


Example of a Hip Roof - Source: Wikipedia

A hip roof is a type of roof where all sides slope gently downwards towards the walls. Therefore, the roof has no gables or vertical sides. The faces of the roof meeting at external corners are known as the hips.


Joists are beams typically arranged in parallel series design to support a floor or ceiling.

Notice how the joists run perpendicular to the larger floor bearers beneath

Linear Load (also know as Triangular, or Triangular Loads)

Linear Loads have a varying magnitude along the length of application. With different start and end magnitudes, examples include triangular and trapezoidal loads.

An example triangular load using ClearCalcs' beam calculator. Note how the magnitude increases along the beam.


A lintel is a horizontal beam running across the top of a door or window. In residential engineering drawings, you'll typically see Lintels denoted on drawings as RL (Roof Lintel) or GL (Garage Lintel) depending on location.

In this example, the lintel is supporting roof load and running across a window opening

Live Load

A live load is a load applied to a structure that is not permanent, and can be variable. People, machines, and stored goods are all examples of live loads.


Forces, stresses, deformations, or accelerations applied to a structure or member.

Young's Modulus (E)

A measure of a structural material's elasticity to deformation under stress. Elastic deformation is non-permanent, meaning the material will return to its original shape after the stress is removed. Our free section properties library has common steel and timber examples, or check out for a huge library of material properties on almost anything you can think of.


Rotational force within a structural member that causes bending moment/stress.

Moment of Inertia (I)

The moment of inertia (also known as the second moment of area) is measurement of the capacity of a cross-section of a member to resist bending. It considers how the cross-sectional area is distributed with reference to a centroidal axis.  It is used to determine the stresses, resistance to buckling and the deflection of the member. The moment of inertia for common steel and timber section can be found in our free section properties library.


Describes the degree or angle of slope of the member - defined as the ratio or total rise to total width.


Purlins are horizontal beams which run parallel to the length of the roof. The purlins support the roof and are supported by rafters or walls.


Rafters describe beams supporting the roof. These beams run perpendicular to the purlins.


A reaction is a force or moment exerted on a member, either by supports or by other connecting members.

The resolved reaction forces for this cantilevered beam are denoted by the arrows underneath each support.

Seismic Load

Loads generated from earthquake-generated agitation.


Shear describes forces which are perpendicular to the longitudinal axis of the member.


Refers to the distance between two supports.

An example beam with span lengths of 3ft and 7ft


A stud is an upright vertical framing member in a building's wall, commonly used to affix wall elements such as plasterboard.

Torsion Load

Torsion describes the twisting of an object due to applied torque.

Uni-Axial Load

Uniaxial loads are those where the load is acting in one direction (axis) only. An example would be where a column is loaded axially through its centroid.  

Wind Beam

A beam loaded on its minor axis, typically not carrying any gravity loads and used to resist lateral wind forces.