STRUCTURAL ELEMENTS

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STRUCTURAL ELEMENTS
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WHAT IS A STRUCTURAL ELEMENT?

• Is a basic component, characteristic or part of a
  structure.
• Usually a large part of the structure
• Not walls, floors or roofs

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BASIC TYPES

• Beams
• Arches
• Columns
• Trusses

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PURPOSES

• Gives form to the structure
• Supports the structure

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BEAMS

• A linear horizontal element used to span a gap
  between two supports.

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BEAMS

• Types
• There are many different types based upon their
  means of support.
• -Simple Have 2 supports at each end.
• -Continuous have a series of equally spaced
• supports along their length.
• -Cantilever are anchored to, and extend from,
  only one support and span less distance.

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BEAM ACTIVITY

• Create the longest spanning beam.
• Criteria
• Must span between two tables
• Use only 1 sheet of paper
• Allowed only 6 of masking tape
• Can not tape either end of beam to table or be
  supported
• Paper tape can be manipulate in any fashion
• Beam can not touch floor
• No other devices can be created to support beam

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BEAM ACTIVITY

• Reflective Questions
• 1. Would this be an effective bridge? Why or why
  not?
• 2. What improvements can be made to this bridge
  to span a longer distance?

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BEAM ACTIVITY 2

• Create the longest spanning beam with supports.
• Criteria
• Must span between two tables
• Use only 1 sheet of paper
• Allowed only 6 of masking tape
• Can not tape either end of beam to table or be
  supported
• Paper tape can be manipulate in any fashion
• Beam can not touch floor

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BEAM ACTIVITY 2

• Reflective Questions
• 3. Would this be an effective bridge? Why or why
  not?
• 4. What improvements can be made to this bridge
  to span a longer distance?

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BEAM ACTIVITY 3

• Create the longest spanning cantilever beam.
• Criteria
• Must span over one edge of a table
• Use only 1 sheet of paper
• Allowed only 6 of masking tape
• Can not tape end of beam to table or be supported
• Paper tape can be manipulate in any fashion
• Beam can not touch floor

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BEAM ACTIVITY 3

• Reflective Questions
• 5. Would this be an effective bridge? Why or why
  not?
• 6. What advantage or disadvantage does this beam
  type have over the others?

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BEAM CHARACTERISTICS

• Tend to sag or bend when supporting a weight
• This change can cause a structure to fail
• Understanding the importance of the depth-to-span
  ratio will help eliminate this
• As the span between supports increases, depth of
  the beam must also increase

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ARCHES

• A curved structural element that spans an open
  space, providing height.
• Developed thousands of years ago
• Built by stacking a series of wedge shaped blocks
  called voussoirs in a curved manner

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ARCHES

• Two types of arches
• 1. Fixed are rigid and set in place. More
  sensitive to thermal expansion and contraction.
• Ex best for short spans doors/windows
• 2. Hinged are more flexible and can accommodate
  movements created by thermal effects and
  foundation shifts
• Ex Long spans bridges roofs

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ARCH CHARACTERISTICS

• Tendency is to push outward at bottoms
• This outward push is called Thrust
• Span-to-rise ratio As span increases in relation
  to the rise, thrust will also increase

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ARCH CHARACTERISTICS

• 3 techniques used to control thrust
• Ties
• Buttresses
• Modify span/rise ratio

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ARCH ACTIVITY

• Create the tallest Arch.
• Criteria
• Height will be measured from the center to the
  top
• Use only 1 sheet of paper
• Allowed only 6 of masking tape
• Can be taped or supported to the table
• Paper tape can be manipulate in any fashion

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ARCH ACTIVITY

• Reflective Questions
• 7. Did you encounter thrust problems? Why or why
  not?
• 8. What could have been done differently to
  reduce the thrust? If no thrust problems how
  could you make the arch taller?

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COLUMNS

• A linear, circular, vertical element used to
  support beams or other elements.
• Different types
• Piers short, stout, massive columns used as
  main vertical supports In bridges
• Piles are foundation supports driven deep into
  the ground
• Pillars columns with different cross-sectional
  shapes other than circular

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COLUMN CHARACTERISTICS

• 2 major problems are crushing and/or buckling
• Usually over designed to avoid this problem
• Diameter-to-length ratio
• General rule if length of column is doubled, it
  will only be able to support ¼ the weight

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COLUMN ACTIVITY

• 1. Cut 2 sheets of paper 10 x 5.
• 2. With 1 sheet of paper (10 x 5), construct a
  column with a 1 diameter. Determine the maximum
  weight held ( of books) before it buckles. Use
  a 1 piece of tape in middle.
• 3. Now create with other piece of paper (5 x
  10), the same column and test for maximum
  weight.

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COLUMN ACTIVITY

• Reflective Question
• 9. How does the length of a column change its
  potential to hold weight?

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TRUSSES

• An arrangement of linear members connected
  together to form a series of triangles lying in a
  straight plane.