Types of beam

[edit] Introduction

Beams are structural elements that resist loads applied laterally to their axis. They typically transfer loads imposed along their length to their endpoints where the loads are transferred to walls, columns, foundations, and so on.

Beams may be:

Simply supported: that is, they are supported at both ends but are free to rotate.
Fixed: Supported at both ends and fixed to resist rotation.
Overhanging: overhanging their supports at one or both ends.
Continuous: extending over more than two supports.
Cantilevered: supported only at one end. See Cantilever for more information.

They may be statically determinate, that is, their reactions can be solved using equilibrium conditions, or they can be statically indeterminate.

Historically, beams were formed from timber, but they may also be manufactured from steel or concrete or they may be composite constructions.

A wide variety of cross-section shapes are commonly available, including; square, rectangular, circular, I-shaped, T-shaped, H-shaped, C-shaped, tubular, and so on.

Beams may be straight, curved, or tapered.

[edit] Common beams (not comprehensive, please add to this list)

[edit] Universal beam

A universal beam (UB) is a beam with an 'I' or 'H'-shaped cross-section available in a variety of standard sizes. It is a very efficient form for carrying bending and shear loads in the plane of the web.

The standard method for specifying the dimensions of a standard hot-rolled steel section includes using initials to designate the type of section. For example:

'UB 203 x 133 x 25' – A universal beam of nominal dimensions 203 mm deep, 133 mm wide, and weight 25 kg/m.

[edit] Trussed beam

Trussed beams are strengthened by the addition of cables or rods to form a truss

[edit] Hip beam

Hip beams are common in roofs, where they form the angled, inclined hip of the roof, supporting other load-bearing beams (or rafters) that branch away from them on either side and slope down to the eaves.

[edit] Composite beam

Composite beams are beams formed from two or more dissimilar materials, such as concrete-steel beams. Downstand beams, flitch beams, and shallow floors are examples of composite beams.

See concrete-steel composite structures for more information

[edit] Open web beam

Open web beams are commonly used for structures that require long spans with light-to-moderate loading.

See Open web beam for more information.

[edit] Lattice beam

Lattice beams are an alternative to open web beams and can be used for spans of up to 15 m with high depth-to-weight ratios. They can be plate girder lattice beams or tubular lattice beams.

See Lattice beam for more information.