Tony Freidman

• Graduate of University of Missouri – Rolla
– B.S. in Civil Engineering
– B.S. in Architectural Engineering
– Research in Architectural specialties
– Research on V-T-M diagram development for reinforced concrete column design
• Currently enrolled as a Ph.D. student at
Washington University – St. Louis
– Research on MR Damper performance
– Research on Structural Health Monitoring

• http://www.youtube.com/watch?v=uKeENd yIluI&feature=related
• http://www.youtube.com/watch?v=AsCBKfRNRk&feature=related
• http://www.youtube.com/watch?v=YCfgfcc pHpc&feature=related
• http://em-ntserver.unl.edu/Mechanics-
Pages/Group1/sld001.htm

“ Engineers shall hold paramount the safety, health and welfare of the public and shall strive to comply with the principles of sustainable development in the performance of their professional duties. “
- 1 st Fundamental Engineering Canon

• What is a Structural Engineer?
• What do they do?
• What do they design?

• What is a Structural Engineer?
• What do they do?
• What do they design?

• Engineer
– Mathematics of design
• Architect/Artist
– Vision
– Aesthetics of design
• Mediator
– Liason between parties on a project
• Salesman
– Must sell your idea, yourself

• What is a Structural Engineer?
• What do Structural Engineers do?
• What do they design?

• Designer
– Consultant
• Take a design, and fit a structural system to that
• Expert witnesses in lawsuits
– Inspector
• Fieldwork, Job site inspections
• Oversee the materials (concrete, steel, etc.)
• Inspect the building – pre- and post-construction
– Demolitions
• Building deconstruction
• Structural Retro-fits

• What is a Structural Engineer?
• What do Structural Engineers do?
• What do they design?

• What is a structure?
– A system designed to resist or support loading and dissipate energy
• Building Structures
– Houses
– Skyscrapers
– Anything designed for continuous human occupation
• Non-building Structures
– Bridges
– Tunnels
– Dams

• Influence on an object that causes a change in a physical quantity
• Considered “vectors” – magnitude and direction
• Static Force
– Unchanging with time
• Walls
• Floors
• Dynamic Force
– Changing with time
• People
• Furniture

• Axial Forces
– Acting along one axis, directly on a point or surface
• Momential (Bending) Force
– Acting along an axis, at a certain distance from a point, causes a folding motion
– M = F*d
F

• Tensile Force
– Pulling on an object – stretching it
– Steel shows “necking” when too much tensile force is applied
• Compressive Force
– Pushing on an object – collapsing it
– Concrete crushes when too much compressive force is applied

• Strain
– Tensile-related property
– Deformation / Length
• Stress
– Compression-related property
– Force / Area
• Compare using stressstrain graph

• Loading is a force being enacted on the structure
– Many sources of load
• Gravity/Weight
• Wind
• Snow
• Earthquake
• Man-made
– Two Types of Structural Loading
• Dead Loads – static, ever-present (i.e. Walls, Floors, etc)
• Live Loads – dynamic, changing (i.e. People, Desk, etc)

• Common Structural Materials
– Timber
– Masonry
– Concrete
– Steel
– Composites

• Common Material Properties
– Strength – Tensile/Compressive
– Density
– Hardness
– Ductility / Brittleness
– Elasticity
– Toughness

• Ability of a material to withstand loading
– Tensile strength – ability of a material to withstand a pulling force
• Steel is good at this, but concrete performs very poorly.
• http://www.youtube.com/watch?v=YdqvGGFIbfc
– Compressive strength – ability of a material to withstand a pushing force
• Wood, concrete, steel, and masonry perform well
• http://www.youtube.com/watch?v=WC6AgX2N1Go&feature=r elated
• http://www.youtube.com/watch?v=i5qwvtEqC5o&fe ature=related

• Mass per unit volume of a material
– Units – mass/vol - kg/m 3 or lb-m/ft 3
– Typically, materials with a high density are very strong and offer great protection.
– However, a high density means that they are heavy and difficult to work with $$$$$

• Ability of a material to resist permanent deformation under a sharp load
– Relates to the elasticity of a material
– Diamond is a very hard substance. If we built a wall out of diamond, we could be sure that very few things would scratch it.
– However, Diamond is incredibly expensive and not as tough as other engineering metals.
It wouldn’t stand up as well in impact loading versus other materials.

• Ability of a material to deform without fracture
– We want materials with high ductility, because they will indicate structural failure without a sudden collapse.
– http://www.youtube.com/watch?v=BXpqW9B0 eT4&feature=related – “Brittle failure”

• Ability of a material to deform and return to it’s original shape.
– Important quantity
• Young’s Modulus
• Ratio of stress to strain
– Stress = Force / Area (lbs./in 2 or N/m 2 )
– Strain = Deformation / Length (unitless)
• Generates a stress-strain graph
• Related to the ductility of a material

• Ability of a material to resist fracture when stressed (amount of energy absorbed per unit volume)
– Units – J/m 3 or Lb-f/ft 3
– Area under the stress-strain curve, evaluated from 0 to the desired strain.

• Advantages
– Cheap, renewable resource
– Good in Tension – ~40 MPa
• Disadvantages
– Susceptible to fire, nature
– Not very hard
– Not very strong
– Limits on shape, size

• Concrete blocks, clay bricks
– Advantages
• Large compressive strength
• Cheap
• Good thermal properties – holds heat well
– Disadvantages
• Not a cohesive material. The strength could depend on the mortar, other factors
• Poor tensile strength, unless reinforced
• Heavy material, requires skilled laborers to use $$$$$
• Height restriction
• Susceptible to the weather

• Combination of water, cement, small aggregate, and large aggregate.
• Advantages
– Very versatile – can be modified with admixtures for different effects
– High compressive strength (4~7 ksi)
– Fire resistant
– Many diverse sizes and shapes - formwork

• Disadvantages
– Long curing time
– Low tension strength (~0.4 ksi)
– Fails in shear, unless reinforced
– Fairly heavy material to work with

• Advantages
– High tensile and compressive strength (A36
Steel ~ 60 ksi)
– Many varieties, depending on your need
• Carbon steel
• Stainless steel
• Galvanized steel
– Elastic material
– Ductile material
– Many shapes, sizes

• Disadvantages
– Expensive – limited quantities / competition
– Susceptible to fire, rust, impurities

• Reinforced Concrete
– Concrete with steel reinforcement
• Concrete handles compression
• Steel takes the tension
– Can handle nearly 4 times the loading that concrete alone can handle
– More expensive material
– http://www.youtube.com/watch?v=dGbrp7Mfp
2w

• Engineered compounds that have different physical or chemical properties
– FRP – Fiber reinforced polymers
– CFRP – Carbon-fiber reinforced polymers
– Plastics
– Categories of Glass
– Categories of Wood

• Rectangle / Square
• Triangle
– Interested in stability
• Truss
• Geodesic Dome

• Split into teams of 5
• Build a triangle and square
• See which shape is the most stable
– Can the unstable shapes be made stable?
– How?

• Advantages
– Proficient in resisting vertical load.
• Disadvantages
– No lateral support

• Advantages
– Able to withstand lateral & vertical loading
– Many triangular shapes available
• Disadvantage
– Wide base = $$$$

Need another bar for lateral support!
--BRACING--
• Advantages
– Proficient in resisting vertical load.
• Disadvantages
– No lateral
(horizontal) load support

• Combination of square and triangle

• Combination of square and triangle
Squares

• Combination of square and triangle
Triangles

• Combination of square and triangle
– Both vertical and lateral support

• Advantages
– Very strong shape, gets strong as the dome size increases
– Perfect load distribution
– No need for structural supports
– Great aerodynamic performance

• Beams
• Girders
• Columns
• Floors
• Foundations
Column Girder
Beam

• Floor
• Beams
• Girders
• Columns
• Foundation
• Soil/Bedrock

• Support the building
– Typically attached to columns
• Types
– Shallow
• Spread footing – concrete strip/pad below the frost line
• Slab-on-grade – concrete pad on the surface
– Deep
• Drilled Shafts
• Piles

• Carry the load from floors to the foundation
– Never want the columns to fail COLLAPSE
– Typically reinforced concrete or steel
– Many sizes and shapes

• Attached columnto-column
– Take the load from the beams
– Transfer it to the columns
– Generally shaped as an I-Beam

• Attached between the girders
– Take load from the flooring system
– Transfer it to the girders
– Generally solid squares, I-beams

• Composed of a subfloor and floor covering
– Usually leave space for ductwork, wiring, etc.
– Floor covering ranges from application to application

•
Geodesic Dome
– http://www.ecophotoexplorers.com/images/antarctica/Dome.jpg
•
Truss
– http://www.classictruss.com/art/wodd_truss_types_examples.gif
•
Truss 2
– http://www.wwta.ab.ca/images/pic%201.jpg
•
Truss 3
– http://www.garrettsbridges.com/images/pratt-truss-bridge.jpg
•
Stress-Strain
– http://www.mittalsteel.com/NR/rdonlyres/8E6DAA96-67F0-4C32-8702-
FB02211647D9/0/InlandAutoApps_MildCS_ssGraph.gif
• Crushing Concrete
– http://images.google.com/imgres?imgurl=http://cee.engr.ucdavis.edu/faculty/chai/Research/P lanar%2520Wall%2520Stability/Wallcolumn5.jpg&imgrefurl=http://cee.engr.ucdavis.edu/facul ty/chai/Research/Planar%2520Wall%2520Stability/structwalls.htm&h=432&w=293&sz=38&hl=en&start=10&sig2=u3TW2TnwJ_IRSpfaQhJuUQ&tbnid
=7g-
JN0VhU59wxM:&tbnh=126&tbnw=85&ei=qUTYR56oL6jmigGFuaiFAg&prev=/images%3Fq%
3Dconcrete%2Bcrushing%2Bcompression%26gbv%3D2%26hl%3Den

• Pile Machine
– http://upload.wikimedia.org/wikipedia/commons/5/54/DFmachine.JPG
• Pile Machine 2
– http://upload.wikimedia.org/wikipedia/commons/8/8b/PileDriving.jpg
• Foundation Type
– http://upload.wikimedia.org/wikipedia/en/6/66/Found-House-Apt.png
• Rebar Cage
– http://i.pbase.com/u29/camera0bug/upload/17213579.P5070031.JPGco
py
• Circular Columns
– http://web.mit.edu/istgroup/ist/images/research_images/microwave/figur e1.gif

• Timber
– http://www.certified-teak.com/images/timber_india.jpg
– http://www.timberframeworks.com/images/File0001.jpg
• Steel
– http://www.lakewoodconferences.com/direct/dbimage/50261363/Stainle ss_Steel_Seamless_Tubes.jpg
– http://ocw.mit.edu/NR/rdonlyres/Global/6/695E8EC6-5161-4B05-B6F1-
8BE09DC40F68/0/chp_steel_struct.jpg
• Concrete
– http://www.lakewoodconferences.com/direct/dbimage/50261363/Stainle ss_Steel_Seamless_Tubes.jpg
– http://www.imagico.de/pov/pict/concrete.jpg
• Masonry
– http://www.gomedia.us/arsenal/images/texturepacks/masonry-prev1.jpg
– http://www.cca.org.nz/images/masonry.jpg

• Structural Engineer
– http://vaengineer.com/images/mr__snell_0462.jpg
• Building
– http://www.brasfieldgorrie.com/_images/portfolio/84/2.jpg
• Girder
– http://www.popartuk.com/g/l/lgfp0432+men-on-a-girder-having-lunchnew-york-city-collection-poster.jpg
– http://oldcooperriverbridge.org/small/oct_31_1927_pearman_resting_gir der.jpg
• Beam
– http://www.cedar-log-homes.com/log-homes-images2/beams-glulam-
6.gif
• Flooring
– http://www.domoteck.org/domoteck_com_images/floor_cross_section.jp
g