Principles of Construction

1
Principles of Construction

• Construction systems are broadly divided into
  four material groups
• Wood
• Steel
• Masonry
• Concrete

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Principles of Construction

• Building are also divided into two types of
  structures

Skeleton-frame
Bearing-wall
Open self-supporting framework
Solid walls for support
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Principles of Construction

• The design of architectural structures directly
  involves the laws of physics.
• The design must support the load of the building
  and the forces acting upon it.
• The roof is supported by wall framework, interior
  partitions, or columns.
• Walls are supported by the ground and roof.
• The exterior walls are supported by the
  foundation, which is supported by the footings.
• The footings distribute the entire load of the
  structure over the soil.

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Principles of Construction

• A-Frame and Arc construction are supported
  directly to the foundation.

5
Principles of Construction

• Structural Forces
• Compression (flattening affect)
• Tension (Pulling force)
• Shear (Sliding resistance)
• Torsion (Twisting force)
• See next slide

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Principles of Construction

• Structural Forces

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Principles of Construction

• Loads
• Live loads The weight of all moveable objects,
  such as people, furniture, snow, rain, wind, ice,
  etc.
• Dead loads The weight of building material and
  permanent objects such as the framing, walls,
  brick, windows, roof and roof materials.
• Building load is the total of the live and dead
  loads.

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Principles of Construction

• Loads
• Lateral (Horizontal) loads Wind, earthquakes.
• Roof loads are measured in PSF. The combined
  load for wind and snow in the central/western
  U.S. is 30 PSF, so our roof designs must be able
  to support this live load.

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Principles of Construction

• Loads
• This table shows some of the typical dead loads
  for standard construction

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Principles of Construction

• Loads

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Principles of Construction

• Loads
• High pitch roofs withstand snow loads better than
  wind loads because of the forces applied to them.
  However, low pitch roofs withstand wind loads
  better than snow loads.

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Principles of Construction

• Resistance
• A structural member must always be equal to or
  greater than the force applied.
• To achieve good design the building loads,
  material, size, shape, placement and spacing must
  be carefully planned.
• Strength of Materials
• The materials capacity to support loads by
  resisting compression, tension, shear, and
  torsion forces or stresses.

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Principles of Construction

• Strength of Materials
• Deflection
• This is the stress result from both compression
  and tension forces acting a structural member.

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Principles of Construction

• Strength of Materials
• Shape
• Different shapes of a material influences its
  ability to support loads.
• Flat sheet of paper verses a folded sheet of
  paper.
• Corrugation
• Creases in sheet metal panels (Duct work)

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Principles of Construction

• Strength of Materials
• Placement
• Most materials are somewhat flexible until
  anchored into the structure.
• Members with their widest dimension positioned
  parallel to the load direction will resist
  greater loads than members placed with their
  smallest dimension in the load direction.

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Principles of Construction

• Strength of Materials
• Spans and Spacing
• Spacing is the distance between parallel
  structural members.
• Span is the distance a member extends between
  vertical supports.
• Decreasing the span while using the same
  structural members can increase the load-bearing
  capacity of each member.

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Principles of Construction

• Strength of Materials
• Cantilever
• A structural member that has only one end of a
  horizontal structural member supported.

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Principles of Construction

• Strength of Materials
• Cantilever

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Principles of Construction

• Strength of Materials
• Equilibrium
• When the center supports equal dead loads on all
  sides.
• Roof overhangs, balconies, and decks are
  structural features that are often cantilevered.

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Principles of Construction

• Modular Construction
• Pre-constructed parts or components of a
  building.
• Modular components are designed to fit together
  with precision.
• Modular Components
• Pre-assembled wall sections, windows, and molded
  bathrooms.

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Principles of Construction

• Size Standardization
• Measurements divisible by the same base unit.
• A module of 3 includes material that measures
• 3, 6, 9, 12, etc.
• A module of 4 includes material that measures 4,
  8, 12, 16, 20, etc.
• This design involves all three dimensions that
  must be standard. L X W X H
• U.S. Standards allow all modules to fit on a 4 X
  8 panel. Pg. 443

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Principles of Construction

• Modular Construction
• Precut
• Materials that are cut to specific sizes and
  assembled on site.
• Prefabricated Holmes
• Major components (walls, decks, partitions) are
  built and assembled at the factory
• Electrical, plumbing, and heating systems finish
  work is done on site

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Principles of Construction

• Modular Construction
• Prebuilt Holmes
• Built totally at the factory.
• Includes HVAC, electrical, and plumbing
• Most states restrict widths on roadways to 14
• Two 14 sections of a 28 house can then be
  shipped on the roadways and assembled onsite.
• Prebuilt Modules
• Modules that can be combined to form a variety of
  floor plan shapes
• Lanai (la-ni)
• Porch, Veranda

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Principles of Construction

• Modular Drawings
• Horizontal and vertical members are drawn to
  align with grid lines
• The total thicknesses of all of these walls must
  be subtracted from the overall modular dimension
  to obtain the correct inside dimension.
• Locate dimensions (walls) on 16, 24, and 48.
• A good way to draw to modular units is to set the
  CAD program to 4 SNAP increments.