Building Construction 3: Reinforced Concrete Beams, Roof Decks
Spandrel Beam
A beam that runs along the outside edge of a floor or roof; can support a nonbearing curtain wall.
inclined tensile stresses
If a concrete beam is reinforced with longitudinal steel only, these diagonal stresses tend o produce cracks which are vertical at the center of the span and become more inclined as they approach the support where they slope towards the center at an angle of about 45.
bend, lengthen or shorten
The loads that act on the beam, as well as the weight of the beam itself, tend to ____ rather than ____
tension, compression
The lower part of the beam is said to be in ___, while the upper part is in ___.
diagonal tension
The stresses that cause these cracks; to prevent failure due to this, additional reinforcing bars are used
Cantilever Beams
The tensile reinforcement is located at top of the beam and inverted U-stirrups are provided.
bottom
the reinforcement of a beam is placed near the ____ of the section.
Beam with Compression Reinforcement
type of beam no bent up bars are required; Beams with compression reinforcement are used when the cross-sectional dimensions of the beam are limited by architectural or structural conditions so that there is an insufficient concrete area for the compressive stresses.
reinforced concrete beams
designed to act together with longitudinal and web reinforcement in resisting applied forces
Reinforced concrete roof slabs
formed and sitecast in the same manner as concrete floor systems. Roof decks are normally covered with a type of membrane roofing for insulation and waterproofing.
metal anchor
may be cast into a spandrel beams to secure the curtain wall panels.
web reinforcement
method(s) of placing reinforcement to prevent or resist shear stress; turn up some of the tensions steel or use vertical stirrups
90, 135, 180 deg.
standard hook
Semi-continuous beam
It is a beam type supported by a hinge/roller at one end and the other end is projecting beyond a fixed support.
Bent Bar
Longitudinal bar bent to an angle of 30 degrees or more with the axis of a concrete beam, perpendicular to and intersecting. Cracking. Could occur from the diagonal tension
roof decks
Reinforced concrete roof slabs other term
Beam brackets or Corbels
Short beam extensions from columns used to support rafters or trusses
Simple beams
These are beams having a single span with a support at each end, there being no restraint at the supports.
Continuous beams
These are beams resting on more than two supports
Cantilever beams
These are beams that are supported at one end only, or they may be that portion of beams projecting beyond one of its supports.
Beam with Compression Reinforcement
These are beams with reinforcement in the compression as well as the tension side of the beam, hence they are also called double reinforced beams.
Hollow box girders
These are double reinforced beams used for long spans. In order to reduce the dead load (the weight of the beam) it is hollowed in the center of the section; Diaphragms are provided at intervals throughout the length of the beam.
downwards, elongated, compressed
When a beam is subjected to ____ at the middle, the lower part of the beam being _____ while the upper part is ____.
T-beams
When a reinforced concrete floor slab and its supporting beam (or girder) are built at the same time and thoroughly tied together, a part of the slab may be considered to act with upper part of the beam in compression.
inflection point
a beam at which the bending moment changes from positive to negative
girder
a term applied to a beam that supports one or more smaller beams, as concentrated loads.
semi-continuous
also frequently used in reinforced-concrete; It refers to a beam having two spans with little or no restraint at the two extreme ends of the beam.
Stirrups
bent reinforcing bars; should always have hooks at the ends to provide anchorage to resist the tensile stresses.
beam
defined as a structural member, resting on supports usually at its ends, which supports transverse loads.
