Structural Elements
Table of Contents
- 1 What are Structural Elements?
- 2 Basic Structural Elements
- 2.1 Ties
- 2.2 Struts
- 2.3 Beams
- 2.4 Columns
- 2.5 Diaphragms
- 3 Properties and Classifications of Various Structural Elements
- 3.1 Beams
- 3.1.1 I-Beam
- 3.1.2 C-Channel
- 3.1.3 Equal Angle Channel
- 3.1.4 Area Moment of Inertia of Beams
- 3.2 Columns
- 3.2.1 Classification
- 3.3 Struts
- 3.3.1 Classification
- 3.4 Ties
- 3.4.1 Classification
- 3.1 Beams
- 4 References
- 4.1 Contributors:
What are Structural Elements?
Structural elements are indivisible pieces that combine to form a larger structure. They are considered indivisible as they serve as the basic foundation for all structures, and there are no components or features that could be simplified further [1]. Structural elements are used to split a building or construct into multiple smaller pieces to make analysis easier. There are five primary structural elements: ties, struts, beams, columns, and diaphragms [2]. Structural elements can be combined to create much more complex structural systems, these systems can describe buildings, bridges, or any architectural construction.
Basic Structural Elements
Ties
Ties are structural members that are only subject to axial tension, and no other forces [2]. Load is only applied at the ends of the tie, and they are not designed to withstand any bending forces on the member. Ties are most commonly found in the sloped roof of residential housing buildings.
A tie used in conjunction with a beam/strut element [3] |
Struts
Struts are similar but opposite to ties [2]. Struts can also only be loaded at their ends, and cannot withstand bending forces. Unlike ties, however, struts are subjected only to axial compression forces. Similar to ties, struts are also commonly found in the structure of sloped roofs.
A strut and beam being used to support a load, both supported on a column [4] |
Beams
Beams are members which are primarily subject to bending forces along the length of the member [2]. Beams are usually horizontal members which primarily withstand gravity forces. Beams are more commonly seen in industrial or commercial building which have more of a rectangular shape.
Columns
Columns are members primarily subjected to axial compression forces, but can also withstand bending forces [2]. Columns are almost always vertical elements which interlace with grids of beams. Columns are also mostly found in industrial or commercial buildings.
Diaphragms
Diaphragms are flat plate elements. Diaphragms are generally used as floors, or when stiffness is required in walls [2]. Diaphragms span or connect beams and columns. Diaphragms are found in almost every type of structure as they take the shape of floors or walls.
A diaphragm supported on two shear walls [5] |
Properties and Classifications of Various Structural Elements
Beams
Beams come in various different cross sections based on the requirements in that scenario. They are always primarily classified by the type of beam, such as I-beam, wide flange, etc..
I-Beam
Beams are usually characterized and listed by their depth dimension. Many catalogues list the full properties of each individual beam including the moment of inertia, cross sectional area, and weight per unit length.
Beams are characterized by the following dimensions, shown on the diagram to the right:
Other dimensions of I-Beams include:
There are a variety of different types of I-beams, such as wide flange, and tapered flange.
For a full table of dimensions and parameters for I-Beams, see https://www.engineeringtoolbox.com/i-flange-steel-beams-d_1317.html
Different beam types can also be located on Engineering Toolbox.
Cross Section of a Normal I-Beam [6] |
 |
|---|