alias STRUCTURE
UNDERSTANDING the
LOAD CARRYING SYSTEM
of BUILDINGS
SYSTEM
•Method of approach to understanding
•Collection of interrelated elements
•Various aspects of elements and relationships
•Problems related to the whole system
STRUCTURE
•Multiple structures in a system.
•Abstract notion describing interrelationship of elements
•Many different representations (verbal, graphical, mathematical).
MY FAMILY SYSTEM
Mother Father Foster mother
MeBrother SisterBrother in Law
Sister in Law Wife
Nephew Son Daughter NieceDaughter in Law
Son in Law
GranddaughterGrandson
STRUCTURE of MARRIAGESMATHEMATICAL REPRESENTATION
Foster Sister Daughter
Mother Mother Wife Daughter Sister in Law in Law
Father 1 1 0 0 0 0 0Me 0 0 1 0 0 0 0Son 0 0 0 0 0 0 1Son in Law 0 0 0 1 0 0 0Brother 0 0 0 0 0 1 0Brother in Law 0 0 0 0 1 0 0
PARENTAGE STRUCTURE
Mother Father Foster mother
MeBrother SisterBrother in Law
Sister in Law Wife
Nephew Son Daughter NieceDaughter in Law
Son in Law
Grandson Granddaughter
GRAPHICAL REPRESENTATION
A SIMPLE BUILDING PLAN
Exterior
Corridor
Reception
SecretaryBoss Room 1
Hall
Room 2Room 3Room 4
CIRCULATION STRUCTURE
Reception
Secretary
Boss
Corridor
Exterior
Room 1
Hall
Room 2
Room 3Room 4
WHY BUILDINGS?
•Security (predators, pests, enemies, etc.)
•Meso-environment (thermal, acoustic, light)
PROBLEMS in BUILDINGS
• Problem specific structures
• Problems and factors
• Nearly all elements involved
HUMAN FACTORS
• Cultural (meanings, use patterns, etc.)
• Psychological (spatial perception, spatial cognition)
• Physiological (thermal comfort)
• Social (spatial layout)
ENVIRONMENTAL FACTORS•Climatic (thermal, radiation, wind, rain, snow, etc.)
•Topographical (slopes, vegetation)
•Geological (gravitation, earthquakes, materials, foundations)
•Economic (materials, labor, finance)
MECHANICAL FACTORS
•Foundations
•Mechanics (forces and motions)
•Loads (gravitation, wind, earthquakes)
LOAD CARRYING SYSTEM(LCS)
• Elements + connectivity structure
• STRUCTURE of building
• Structural problems
A SIMPLE BUILDING LCS
Slab
Beam 1 Beam 2
Beam 3Beam 4
Col
umn
1
Col
umn
2 Col
umn
3
Col
umn
4
Wall 1 Wall 2
BUILDING ELEMENTS
C1 C2 C3 C4
Slab
Wall 1 Wall 2
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 REQUIREMENTSof 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
•Displacements/deformations
LoadInternal force
Load
•Internal forces
•Energy storage
•Language of description is mechanical.
UNDERSTANDING BEHAVIORof 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
•3D forms - solid, systems of 1D and 2D forms
•Dimensionality
•1D forms - rod, planar curve, spatial curve
•2D forms - plane, surface, systems of 1D forms
•Orientability
MECHANICAL FORM
•Combination of geometric form and load
Orientation
Load
Geometric
Form
•Mechanical form = Oriented and loaded geometric form
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
ARCH
Load Orientation
Load
Load Orientation
CURVED BEAM
Arch
Curved Beam
Spatial
Curved Beam
MECHANICAL FORMS(SLAB and WALL)
Geometric Form = PLANE
Load
WALL
Load Orientation
Load
Load Orientation
SLAB
Slab
Folded Plate
MECHANICAL FORMS(SHELL)
Load
Shell
Dome
UNDERSTANDING SPECIFICBUILDING 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 Tower
s
SKYSCRAPER(overall building scale)
Gravitation
MF = COLUMN
Windor
Earthquake
MF = BEAMGF = ROD
SKYSCRAPER(main structure scale)
GF = PLANE GF = PLANE
Gravitation
MF = SLAB
MF = WALL
Gravitation
MF = WALL
Earthquake
Sears Towe
r
SKYSCRAPER(detail scale)
GF = PLANEGF = ROD
LateralLoad
MF = BEAM
Weight
AxialLoad
MF = COLUMN
AxialLoad
Weight
MF = SLAB
BEHAVIOR of the BEAM
BENDING MOMENT SHEAR
INTERNAL FORCES
BEHAVIOR of the COLUMN
Compression Tension
INTERNAL FORCES
COMPRESSIVE AXIAL FORCE
TENSILE AXIAL FORCE
BEHAVIOR of the COLUMN (BUCKLING)
BENDING MOMENT
INTERNAL FORCE
Load
DESIGN for BENDING•Provide material away from the center.
I beamRC beam
•Provide the right kind of material.
DESIGN for SHEAR
Truss
Provide diagonals
I beam
Castella beam
Welding
DESIGN for COMPRESSION
AGAINST BUCKLINGProvide this material away from the center.
Provide the necessary material in axial form.
TWO BASIC PROBLEMS
1. Space enclosure.
2. Provision of horizontal levels.
Planes of equal potential energy
CONCLUSION
•Look at a building LCS hierarchically.
•Identify the predominant loading.
•Identify the geometric form.
•Identify the mechanical form.
•Estimate the behavior.