Docstoc

Struct

Document Sample
Struct Powered By Docstoc
					 UNDERSTANDING the
LOAD CARRYING SYSTEM
    of BUILDINGS

   alias STRUCTURE
               SYSTEM
•Method of approach to understanding

•Collection of interrelated elements

•Various aspects of elements and relationships

•Problems related to the whole system
      STRUCTURE
•Abstract notion describing
  interrelationship of elements

•Many different representations
(verbal, graphical, mathematical).


•Multiple structures in a system.
              MY FAMILY SYSTEM
    Mother                         Father                                  Foster mother


Sister                                                                             Brother
in Law       Brother        Me                  Wife              Sister           in Law



Nephew           Son    Daughter       Son             Daughter            Niece
                        in Law         in Law


                 Grandson                   Granddaughter
         STRUCTURE of MARRIAGES
                 MATHEMATICAL REPRESENTATION

                           Foster                               Sister   Daughter
                  Mother   Mother   Wif e   Daughter   Sister   in Law   in Law
Father              1        1       0         0         0        0         0
Me                  0        0       1         0         0        0         0
Son                 0        0       0         0         0        0         1
Son in Law          0        0       0         1         0        0         0
Brother             0        0       0         0         0        1         0
Brother in Law      0        0       0         0         1        0         0
         PARENTAGE STRUCTURE
                       GRAPHICAL REPRESENTATION



    Mother                          Father                                  Foster mother


Sister                                                                              Brother
in Law       Brother         Me                  Wife              Sister           in Law



Nephew           Son     Daughter       Son             Daughter            Niece
                         in Law         in Law


                 Grandson                    Granddaughter
A SIMPLE BUILDING PLAN

  Secretary
                  Boss     Room 1
  Reception
                                    Hall
     Corridor


  Room 4         Room 3    Room 2


                Exterior
CIRCULATION STRUCTURE

                    Room 4                      Room 1
                                   Room 3
           Hall

                              Corridor      Room 2


                                                 Boss
                  Reception
Exterior
                                    Secretary
     WHY BUILDINGS?
•Meso-environment
 (thermal, acoustic, light)


•Security (predators, pests, enemies, etc.)
PROBLEMS in BUILDINGS
   • Problems and factors


  • Nearly all elements involved

   • Problem specific structures
 HUMAN FACTORS
• Psychological
 (spatial perception, spatial cognition)

• Physiological (thermal comfort)


• Social (spatial layout)


• Cultural (meanings, use patterns, etc.)
ENVIRONMENTAL FACTORS
  •Climatic
   (thermal, radiation, wind, rain, snow, etc.)

  •Economic
   (materials, labor, finance)

  •Geological
   (gravitation, earthquakes, materials,
    foundations)
  •Topographical
   (slopes, vegetation)
MECHANICAL FACTORS
•Mechanics (forces and motions)

•Loads (gravitation, wind, earthquakes)

•Foundations
LOAD CARRYING SYSTEM
        (LCS)

  • Elements + connectivity structure


  • STRUCTURE of building


  • Structural problems
    Column 1




                 Column 4

Column 2




      Column 3
                            A SIMPLE BUILDING LCS
          BUILDING ELEMENTS



                        C1   C2   C3   C4
     B1

B2



           B3      B4
STRUCTURE of CONNECTIVITY
                      Slab


   B1            B2            B3         B4


        Wall 1        Wall 2



   C1            C2            C3         C4


    Edge connection                 End connection
STRUCTURAL REQUIREMENTS
                    of LCSs
 • Restraint (sufficient members and supports
   to provide for equilibrium)

 • Strength (sufficient material to prevent
 rupture)

 • Rigidity (sufficient resistance to
 deformation)

 • Ductility (sufficient capacity for energy
 absorption)
         COMPATIBILITY
         REQUIREMENTS
            of LCSs
 • Spatial layout (e.g. hotels, bearing walls)

• Materials (e.g. masonry and vaults)

• Services (integration of services)

• Construction (e.g. bearing walls, integral forms,
  tower cranes)
 STRUCTURAL BEHAVIOR
   •Internal forces

                                             Load
Load
                            Internal force

   •Displacements/deformations

   •Energy storage

   •Language of description is mechanical.
UNDERSTANDING BEHAVIOR
        of LCSs
   •Modeling of LCS

  •Prediction of loads

  •Analysis of mechanical forms

  •Understanding in terms of basic modes
   DIRECTION of
PREDOMINANT LOAD
 •Vertical (gravitation)

 •Horizontal (wind)

 •Combination (earthquake)
      GEOMETRIC FORM
•Dimensionality                •Orientability

•1D forms - rod, planar curve, spatial curve




•2D forms - plane, surface, systems of 1D forms




 •3D forms - solid, systems of 1D and 2D forms
MECHANICAL FORM
•Combination of geometric form and load

•Mechanical form = Oriented and loaded
                   geometric form

                  Load

Orientation
MECHANICAL FORMS
 (BEAM and COLUMN)
        Geometric Form = ROD




Load   Orientation      Load   Orientation

       BEAM                COLUMN
 MECHANICAL FORMS
(ARCH and CURVED BEAM)
  Geometric Form = PLANAR CURVE

                               Load


        Load




 Load   Orientation   Load   Orientation

   ARCH               CURVED BEAM
Arch
Curved Beam
Spatial
Curved
 Beam
MECHANICAL FORMS
  (SLAB and WALL)
       Geometric Form = PLANE
                                Load


       Load




Load   Orientation   Load    Orientation

   WALL                     SLAB
Slab
Folded Plate
MECHANICAL FORMS
     (SHELL)
    Load
Shell
Dome
UNDERSTANDING SPECIFIC
    BUILDING LCS’s
 •Resolve hierarchy of structural problems

•Determine scale of problem
 (overall building, breakdown of main structure,
 detail elements)
 •Resolve structure of elements

 •Recognize the MF of elements
World
 Trade
Towers
       SKYSCRAPER
     (overall building scale)

             Gravitation


                           Wind
                            or
                           Earthquake



GF = ROD   MF = COLUMN        MF = BEAM
 SKYSCRAPER
(main structure scale)
                           GF = PLANE
      GF = PLANE
                           Gravitation
 Gravitation




            Earthquake
                           MF = SLAB


MF = WALL      MF = WALL
Sears
Tower
     Axial
     Load    Lateral   SKYSCRAPER
             Load
                        (detail scale)
       GF = ROD
                                 GF = PLANE

                                   Weight



MF = COLUMN        MF = BEAM
                        Weight
                                 MF = SLAB
               Axial
               Load
BEHAVIOR of the BEAM



        INTERNAL FORCES




BENDING MOMENT       SHEAR
BEHAVIOR of the COLUMN


  Compression         Tension


           INTERNAL FORCES




  COMPRESSIVE          TENSILE
   AXIAL FORCE       AXIAL FORCE
BEHAVIOR of the COLUMN
      (BUCKLING)
                       Load




      INTERNAL FORCE




      BENDING MOMENT
DESIGN for BENDING
•Provide material away from the center.




•Provide the right kind of material.




    I beam
                                 RC beam
                DESIGN for
                 SHEAR
                Provide diagonals


                          Truss



                 I beam

                          Welding

Castella beam
DESIGN for COMPRESSION


  Provide the necessary material in axial form.

             AGAINST BUCKLING
  Provide this material away from the center.
TWO BASIC PROBLEMS


     1. Space enclosure.




                Planes of equal
                potential energy


        2. Provision of horizontal levels.
        CONCLUSION
•Look at a building LCS hierarchically.

•Identify the predominant loading.

•Identify the geometric form.

•Identify the mechanical form.

•Estimate the behavior.

				
DOCUMENT INFO
Shared By:
Categories:
Tags:
Stats:
views:3
posted:11/2/2011
language:English
pages:49