Structural Systems
CM 105
Precast Concrete Framing
• Offer exceptional strength
and resistance to seismic
stresses and high degree
of fire safety
• Concrete framing plans
can be divided into:
column, beam, wall, floor
and roof plans
• Walls are located to their
edges, column to centers
Concrete Tilt-up Plans
• Plans must show the location and size of each panel
• Panels are dimensioned from edge to edge
Cast-in-place Concrete
Floor and Roof Decking
• Other materials, such as the precast
concrete hollow core planks shown
here, can also be used to create the
floor and roof decks.
Fundamentals of Building Construction,
Materials & Methods, 5th Edition
Copyright © 2009 J. Iano. All rights reserved.
Concrete Units and Stone
Stone cladding
http://www.virginiaplaces.org/geology/buildingstones.html
http://www.vt.edu/about/2011-11-11-hokie-stone.pdf
Stone Masonry
• Rubble: Unsquared stone blocks
• Random: Laid without continuous
horizontal joints
• Coursed: Laid with continuous
horizontal joints
Fundamentals of Building Construction,
Materials & Methods, 5th Edition
Copyright © 2009 J. Iano. All rights reserved.
Stone Masonry
• Ashlar: Squared blocks
• Random: Laid without
continuous horizontal joints
• Coursed: Laid with
continuous horizontal joints
Fundamentals of Building Construction,
Materials & Methods, 5th Edition
Copyright © 2009 J. Iano. All rights reserved.
Concrete Masonry Units (CMUs):
• Can be manufactured in a great variety of shapes and
sizes
Fundamentals of Building Construction,
Materials & Methods, 5th Edition
Copyright © 2009 J. Iano. All rights reserved.
Laying CMU
• Mortar is
identical to that
used for brick
masonry.
• Corner leads
are laid first.
• String lines and
levels are used
to keep walls
straight, plumb,
and level.
• Joints are
tooled and the
face of the
blocks cleaned
as work
progresses.
Fundamentals of Building Construction,
Materials & Methods, 5th Edition
Copyright © 2009 J. Iano. All rights reserved.
Wood Floor Framing –
Sill Plate & Girders
Floor Framing – Floor Joists
Floor Framing Plan
Example
Roof Framing Plan Example
Heavy Timber Framing
Courtesy Ryan Wall
Light Gauge Steel
Steel Framing
• Division 5 Metals,
Section 05 40 00—ColdFormed Metal Framing
– Structural, loadbearing framing
– Exterior wall framing (subject to
wind loads)
• Division 9 Finishes
Section 09 22 16—NonStructural Metal Framing
– Interior nonloadbearing framing
Fundamentals of Building Construction,
Materials & Methods, 5th Edition
Copyright © 2009 J. Iano. All rights reserved.
Light Gauge Steel Compared to
Light Wood Framing
• Advantages
– Like wood light framing:
versatile, flexible, simple to
construct
– Noncombustible and immune to
insect attack
– Dimensionally stable, with
consistent material properties
– Lighter weight
• Disadvantages
– Members require more frequent
bracing
– Readily conducts heat and
requires extra attention to
eliminating thermal bridging
effects
– Susceptible to corrosion
Fundamentals of Building Construction,
Materials & Methods, 5th Edition
Copyright © 2009 J. Iano. All rights reserved.
Steel
Steel
Steel Alloys
• Traditional mild steel
– ASTM A36
– Minimum 36 ksi (36,000 lb
per sq. in.) yield strength
• Contemporary highstrength, low alloy steels
– ASTM A992: W shapes
– ASTM A572: other shapes
– Produced economically in
mini-mills
– Minimum yield strength
50 to 65 ksi
• Use of stronger steel
allows savings in weight
and reductions in the size
of structural elements,
reducing overall costs.
ASTM A992 steel columns lay stacked in a fabricator yard.
Note the holes predrilled for connections that will be
completed in the field.
More Steel Alloys
• Weathering steel ASTM
A588
– Surface rust adheres to base
metal, limiting further
rusting
– Mostly used in highway and
bridge structures,
eliminating the need for a
protective coating
– Right: 365-ft span highway
arch bridge made principally
of weathering steel
– Cor-Ten steel (a proprietary
trade name for weathering
steel)
• Stainless steel ASTM A240,
A276
– Added nickel and chromium
– Forms self-protecting oxide
layer that provides long
lasting protection against
corrosion
Fundamentals of Building
Construction, Materials &
Methods, 5th Edition
Copyright © 2009 J. Iano. All rights reserved.
Question?
In a fire, without fire protection a steel beam is
less able to withstand the heat than a timber.
WHY?