I-beam

An I-beam, also known as H-beam, W-beam (for "wide flange"), Universal Beam (UB), Rolled Steel Joist (RSJ), or double-T (especially in Polish, Bulgarian, Spanish, Italian and German), is a beam with an I or H-shaped cross-section. The horizontal elements of the "I" are known as flanges, while the vertical element is termed the "web". I-beams are usually made of structural steel and are used in construction and civil engineering.

The web resists shear forces, while the flanges resist most of the bending moment experienced by the beam. Beam theory shows that the I-shaped section is a very efficient form for carrying both bending and shear loads in the plane of the web. On the other hand, the cross-section has a reduced capacity in the transverse direction, and is also inefficient in carrying torsion, for which hollow structural sections are often preferred.

History

The method of producing an I-beam, as rolled from a single piece of steel, was patented by Alphonse Halbou of the company Forges de la Providence in 1849.

Beam

Beam may refer to:

BEAM

Beam (music)

In musical notation, a beam is a horizontal or diagonal line used to connect multiple consecutive notes (and occasionally rests) in order to indicate rhythmic grouping. Only eighth notes (quavers) or shorter can be beamed. The number of beams is equal to the number of flags that would be present on an un-beamed note.

Grouping

The span of beams indicates the rhythmic grouping, usually determined by the time signature. Therefore, beams do not usually cross bar lines, or major sub-divisions of bars. If notes extend across these divisions, this is indicated with a tie.

In modern practice beams may span across rests in order to make rhythmic groups clearer.

In vocal music, beams were traditionally used only to connect notes sung to the same syllable. In modern practice it is more common to use standard beaming rules, while indicating multi-note syllables with slurs.

Positioning

Notes joined by a beam usually have all the stems pointing in the same direction (up or down). The average pitch of the notes is used to determine the direction – if the average pitch is below the middle staff-line, the stems and beams usually go above the note head, otherwise they go below.

Beam (nautical)

The beam of a ship is its width at the widest point as measured at the ship's nominal waterline. The beam is a bearing projected at right-angles from the fore and aft line, outwards from the widest part of ship. Beam may also be used to define the maximum width of a ship's hull, or maximum width plus superstructure overhangs.

Generally speaking, the wider the beam of a ship (or boat), the more initial stability it has, at expense of reserve stability in the event of a capsize, where more energy is required to right the vessel from its inverted position.

Typical values

Typical length-to-beam ratios for small sailboats are from 2:1 (dinghies to trailerable sailboats around 20 ft or 6 m) to 5:1 (racing sailboats over 30 ft or 10 m).

Large ships have widely varying beam ratios, some as large as 20:1.

Rowing shells designed for flatwater racing may have length to beam ratios as high as 30:1, while a coracle has a ratio of almost 1:1 – it is nearly circular.

Formula

The beam of many monohull vessels can be calculated using the following formula: