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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
http://www.virginiaplaces.org/geology/buildingstones.html
http://www.vt.edu/about/2011-11-11-hokie-stone.pdf
Stone cladding
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—Cold-Formed Metal Framing– Structural, loadbearing framing– Exterior wall framing (subject to
wind loads)
• Division 9 FinishesSection 09 22 16—Non-Structural 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 high-
strength, 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 EditionCopyright © 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?